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drop price data in x data
x_data=df.drop('price',axis=1)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Now we randomly split our data into training and testing data using the function train_test_split.
from sklearn.model_selection import train_test_split x_train, x_test, y_train, y_test = train_test_split(x_data, y_data, test_size=0.10, random_state=1) print("number of test samples :", x_test.shape[0]) print("number of training samples:",x_train.shape[0])
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
The test_size parameter sets the proportion of data that is split into the testing set. In the above, the testing set is set to 10% of the total dataset. Question 1):Use the function "train_test_split" to split up the data set such that 40% of the data samples will be utilized for testing, set the parameter "random_...
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonx_train1, x_test1, y_train1, y_test1 = train_test_split(x_data, y_data, test_size=0.4, random_state=0) print("number of test samples :", x_test1.shape[0])print("number of training samples:",x_train1.shape[0])``` Let's import LinearRegression from the module linear_model.
from sklearn.linear_model import LinearRegression
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We create a Linear Regression object:
lre=LinearRegression()
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
we fit the model using the feature horsepower
lre.fit(x_train[['horsepower']], y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's Calculate the R^2 on the test data:
lre.score(x_test[['horsepower']], y_test)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
we can see the R^2 is much smaller using the test data.
lre.score(x_train[['horsepower']], y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Question 2): Find the R^2 on the test data using 40% of the data for training data
# Write your code below and press Shift+Enter to execute
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MIT
DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonx_train1, x_test1, y_train1, y_test1 = train_test_split(x_data, y_data, test_size=0.4, random_state=0)lre.fit(x_train1[['horsepower']],y_train1)lre.score(x_test1[['horsepower']],y_test1)``` Sometimes you do not have sufficient testing data; as a result, you may want to perform Cross...
from sklearn.model_selection import cross_val_score
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We input the object, the feature in this case ' horsepower', the target data (y_data). The parameter 'cv' determines the number of folds; in this case 4.
Rcross = cross_val_score(lre, x_data[['horsepower']], y_data, cv=4)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
The default scoring is R^2; each element in the array has the average R^2 value in the fold:
Rcross
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We can calculate the average and standard deviation of our estimate:
print("The mean of the folds are", Rcross.mean(), "and the standard deviation is" , Rcross.std())
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We can use negative squared error as a score by setting the parameter 'scoring' metric to 'neg_mean_squared_error'.
-1 * cross_val_score(lre,x_data[['horsepower']], y_data,cv=4,scoring='neg_mean_squared_error')
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Question 3): Calculate the average R^2 using two folds, find the average R^2 for the second fold utilizing the horsepower as a feature :
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonRc=cross_val_score(lre,x_data[['horsepower']], y_data,cv=2)Rc.mean()``` You can also use the function 'cross_val_predict' to predict the output. The function splits up the data into the specified number of folds, using one fold for testing and the other folds are used for training. ...
from sklearn.model_selection import cross_val_predict
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We input the object, the feature in this case 'horsepower' , the target data y_data. The parameter 'cv' determines the number of folds; in this case 4. We can produce an output:
yhat = cross_val_predict(lre,x_data[['horsepower']], y_data,cv=4) yhat[0:5]
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Part 2: Overfitting, Underfitting and Model SelectionIt turns out that the test data sometimes referred to as the out of sample data is a much better measure of how well your model performs in the real world. One reason for this is overfitting; let's go over some examples. It turns out these differences are more appar...
lr = LinearRegression() lr.fit(x_train[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']], y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Prediction using training data:
yhat_train = lr.predict(x_train[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']]) yhat_train[0:5]
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Prediction using test data:
yhat_test = lr.predict(x_test[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']]) yhat_test[0:5]
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's perform some model evaluation using our training and testing data separately. First we import the seaborn and matplotlibb library for plotting.
import matplotlib.pyplot as plt %matplotlib inline import seaborn as sns
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's examine the distribution of the predicted values of the training data.
Title = 'Distribution Plot of Predicted Value Using Training Data vs Training Data Distribution' DistributionPlot(y_train, yhat_train, "Actual Values (Train)", "Predicted Values (Train)", Title)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Figure 1: Plot of predicted values using the training data compared to the training data. So far the model seems to be doing well in learning from the training dataset. But what happens when the model encounters new data from the testing dataset? When the model generates new values from the test data, we see the distr...
Title='Distribution Plot of Predicted Value Using Test Data vs Data Distribution of Test Data' DistributionPlot(y_test,yhat_test,"Actual Values (Test)","Predicted Values (Test)",Title)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Figur 2: Plot of predicted value using the test data compared to the test data. Comparing Figure 1 and Figure 2; it is evident the distribution of the test data in Figure 1 is much better at fitting the data. This difference in Figure 2 is apparent where the ranges are from 5000 to 15 000. This is where the distributi...
from sklearn.preprocessing import PolynomialFeatures
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
OverfittingOverfitting occurs when the model fits the noise, not the underlying process. Therefore when testing your model using the test-set, your model does not perform as well as it is modelling noise, not the underlying process that generated the relationship. Let's create a degree 5 polynomial model. Let's use 55 ...
x_train, x_test, y_train, y_test = train_test_split(x_data, y_data, test_size=0.45, random_state=0)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We will perform a degree 5 polynomial transformation on the feature 'horse power'.
pr = PolynomialFeatures(degree=5) x_train_pr = pr.fit_transform(x_train[['horsepower']]) x_test_pr = pr.fit_transform(x_test[['horsepower']]) pr
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Now let's create a linear regression model "poly" and train it.
poly = LinearRegression() poly.fit(x_train_pr, y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We can see the output of our model using the method "predict." then assign the values to "yhat".
yhat = poly.predict(x_test_pr) yhat[0:5]
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's take the first five predicted values and compare it to the actual targets.
print("Predicted values:", yhat[0:4]) print("True values:", y_test[0:4].values)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We will use the function "PollyPlot" that we defined at the beginning of the lab to display the training data, testing data, and the predicted function.
PollyPlot(x_train[['horsepower']], x_test[['horsepower']], y_train, y_test, poly,pr)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Figur 4 A polynomial regression model, red dots represent training data, green dots represent test data, and the blue line represents the model prediction. We see that the estimated function appears to track the data but around 200 horsepower, the function begins to diverge from the data points. R^2 of the training ...
poly.score(x_train_pr, y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
R^2 of the test data:
poly.score(x_test_pr, y_test)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We see the R^2 for the training data is 0.5567 while the R^2 on the test data was -29.87. The lower the R^2, the worse the model, a Negative R^2 is a sign of overfitting. Let's see how the R^2 changes on the test data for different order polynomials and plot the results:
Rsqu_test = [] order = [1, 2, 3, 4] for n in order: pr = PolynomialFeatures(degree=n) x_train_pr = pr.fit_transform(x_train[['horsepower']]) x_test_pr = pr.fit_transform(x_test[['horsepower']]) lr.fit(x_train_pr, y_train) Rsqu_test.append(lr.score(x_test_pr, y_test)) plt.pl...
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We see the R^2 gradually increases until an order three polynomial is used. Then the R^2 dramatically decreases at four. The following function will be used in the next section; please run the cell.
def f(order, test_data): x_train, x_test, y_train, y_test = train_test_split(x_data, y_data, test_size=test_data, random_state=0) pr = PolynomialFeatures(degree=order) x_train_pr = pr.fit_transform(x_train[['horsepower']]) x_test_pr = pr.fit_transform(x_test[['horsepower']]) poly = LinearRegression(...
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
The following interface allows you to experiment with different polynomial orders and different amounts of data.
interact(f, order=(0, 6, 1), test_data=(0.05, 0.95, 0.05))
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Question 4a):We can perform polynomial transformations with more than one feature. Create a "PolynomialFeatures" object "pr1" of degree two?
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonpr1=PolynomialFeatures(degree=2)``` Question 4b): Transform the training and testing samples for the features 'horsepower', 'curb-weight', 'engine-size' and 'highway-mpg'. Hint: use the method "fit_transform" ?
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonx_train_pr1=pr1.fit_transform(x_train[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']])x_test_pr1=pr1.fit_transform(x_test[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']])``` <!-- The answer is below:x_train_pr1=pr.fit_transform(x_train[['horsepower', 'curb-w...
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonx_train_pr1.shape there are now 15 features``` Question 4d): Create a linear regression model "poly1" and train the object using the method "fit" using the polynomial features?
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonpoly1=LinearRegression().fit(x_train_pr1,y_train)``` Question 4e): Use the method "predict" to predict an output on the polynomial features, then use the function "DistributionPlot" to display the distribution of the predicted output vs the test data?
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonyhat_test1=poly1.predict(x_test_pr1)Title='Distribution Plot of Predicted Value Using Test Data vs Data Distribution of Test Data'DistributionPlot(y_test, yhat_test1, "Actual Values (Test)", "Predicted Values (Test)", Title)``` Question 4f): Using the distribution plot above, exp...
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonThe predicted value is higher than actual value for cars where the price $10,000 range, conversely the predicted price is lower than the price cost in the $30,000 to $40,000 range. As such the model is not as accurate in these ranges.``` Part 3: Ridge regression In this section, we...
pr=PolynomialFeatures(degree=2) x_train_pr=pr.fit_transform(x_train[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg','normalized-losses','symboling']]) x_test_pr=pr.fit_transform(x_test[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg','normalized-losses','symboling']])
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's import Ridge from the module linear models.
from sklearn.linear_model import Ridge
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's create a Ridge regression object, setting the regularization parameter to 0.1
RigeModel=Ridge(alpha=0.1)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Like regular regression, you can fit the model using the method fit.
RigeModel.fit(x_train_pr, y_train)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Similarly, you can obtain a prediction:
yhat = RigeModel.predict(x_test_pr)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Let's compare the first five predicted samples to our test set
print('predicted:', yhat[0:4]) print('test set :', y_test[0:4].values)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We select the value of Alpha that minimizes the test error, for example, we can use a for loop.
Rsqu_test = [] Rsqu_train = [] dummy1 = [] Alpha = 10 * np.array(range(0,1000)) for alpha in Alpha: RigeModel = Ridge(alpha=alpha) RigeModel.fit(x_train_pr, y_train) Rsqu_test.append(RigeModel.score(x_test_pr, y_test)) Rsqu_train.append(RigeModel.score(x_train_pr, y_train))
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We can plot out the value of R^2 for different Alphas
width = 12 height = 10 plt.figure(figsize=(width, height)) plt.plot(Alpha,Rsqu_test, label='validation data ') plt.plot(Alpha,Rsqu_train, 'r', label='training Data ') plt.xlabel('alpha') plt.ylabel('R^2') plt.legend()
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
**Figure 6**:The blue line represents the R^2 of the validation data, and the red line represents the R^2 of the training data. The x-axis represents the different values of Alpha. Here the model is built and tested on the same data. So the training and test data are the same.The red line in figure 6 represents the R^...
# Write your code below and press Shift+Enter to execute
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MIT
DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Click here for the solution```pythonRigeModel = Ridge(alpha=10) RigeModel.fit(x_train_pr, y_train)RigeModel.score(x_test_pr, y_test)``` Part 4: Grid Search The term Alfa is a hyperparameter, sklearn has the class GridSearchCV to make the process of finding the best hyperparameter simpler. Let's import GridSearchCV fro...
from sklearn.model_selection import GridSearchCV
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We create a dictionary of parameter values:
parameters1= [{'alpha': [0.001,0.1,1, 10, 100, 1000, 10000, 100000, 100000]}] parameters1
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Create a ridge regions object:
RR=Ridge() RR
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Create a ridge grid search object
Grid1 = GridSearchCV(RR, parameters1,cv=4)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Fit the model
Grid1.fit(x_data[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']], y_data)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
The object finds the best parameter values on the validation data. We can obtain the estimator with the best parameters and assign it to the variable BestRR as follows:
BestRR=Grid1.best_estimator_ BestRR
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
We now test our model on the test data
BestRR.score(x_test[['horsepower', 'curb-weight', 'engine-size', 'highway-mpg']], y_test)
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
Question 6): Perform a grid search for the alpha parameter and the normalization parameter, then find the best values of the parameters
# Write your code below and press Shift+Enter to execute
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DA0101EN/.ipynb_checkpoints/model-evaluation-and-refinement-checkpoint.ipynb
alekhaya99/IBM-CLOUD-SQL-AND-PYTHON
DESU IA4 HEALHInfo-PROF, Introduction to Python programming for health data Session 2: Introduction to PANDASLeaning objectives1. Learning the different data types in pandas: Data frame and series2. Importing and exporting data into a data frame2. Subseting data frames5. Doing transformations with dataframes What is ...
#Importing Pandas and verifying the version import pandas as pd # as allows to create an alias import numpy as np print(pd.__version__) #allow to verify the pandas function
1.1.5
Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Data types on Pandas :1. **Series :** It is a one-dimensional array holding data of any type.2. **Dataframes :** Multidimensional data tables holding data of any type. We can think that the series are like the columns of a dataframe whereas the whole table is the dataframe.
# Example series with labels a = [1, 7, 2] myvar = pd.Series(a, index = ["x", "y", "z"]) print(myvar)
x 1 y 7 z 2 dtype: int64
Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Dataframes Dataframes are multidiomensional matrices that can store data of different types.
data = { "calories": [420, 380, 390], "duration": [50, 40, 45], "category" : ['a','b','c'] } df = pd.DataFrame(data, index = ["day1", "day2", "day3"]) print(df) students = [ ('jack', 34, 'Sydeny') , ('Riti', 30, 'Delhi' ) , ('Aadi', 16, 'New York') ] # Create a DataFrame object dfObj...
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
**Exercise :** Create a dataframe that stores in one row the person ID, height, weight, sex and birthdate. Add at least three examples [DataFrame attributes](https://pandas.pydata.org/docs/reference/frame.html) Exercise : For the dataframe previously created, go to dataframe attributes and show the following informat...
df['calories']
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
DataFrame.loc | Select Column & Rows by NameDataFrame provides indexing label loc for selecting columns and rows by names dataFrame.loc[ROWS RANGE , COLUMNS RANGE]
df.loc['day1',:] df.loc[:,'calories']
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
DataFrame.iloc | Select Column Indexes & Rows Index PositionsDataFrame provides indexing label iloc for accessing the column and rows by index positions i.e.*dataFrame.iloc[ROWS INDEX RANGE , COLUMNS INDEX RANGE]*It selects the columns and rows from DataFrame by index position specified in range. If ‘:’ is given in row...
df.iloc[:,[0,2]]
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Variable conversion :
df_petit = pd.DataFrame({ 'Country': ['France','Spain','Germany', 'Spain','Germany', 'France', 'Italy'], 'Age': [50,60,40,20,40,30, 20] }) df_petit
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Label encoding : Label Encoding refers to converting the labels into a numeric form so as to convert them into the machine-readable form. Machine learning algorithms can then decide in a better way how those labels must be operated. It is an important pre-processing step for the structured dataset in supervised learnin...
df_petit['Country_cat'] = df_petit['Country'].astype('category').cat.codes df_petit
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
One hot encoding
help(pd.get_dummies) df_petit = pd.get_dummies(df_petit,prefix=['Country'], columns = ['Country'], drop_first=True) df_petit.head()
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
**Exercise :** Create a dataframe with 3 columns with the characteristics : ID, sex (M or F), frailty degree (FB, M, F). Convert the categorical variables using label encoding and one-hot-encoding. Dealing with dates https://pandas.pydata.org/docs/reference/api/pandas.to_datetime.html
#Library to deeal with dates import datetime dti = pd.to_datetime( ["1/1/2018", np.datetime64("2018-01-01"), datetime.datetime(2018, 1, 1)] ) dti df = pd.DataFrame({'date': ['3/10/2000', '3/11/2000', '3/12/2000'], 'value': [2, 3, 4]}) df['date'] = pd.to_datetime(df['date']) df
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Cutomize the date format
df = pd.DataFrame({'date': ['2016-6-10 20:30:0', '2016-7-1 19:45:30', '2013-10-12 4:5:1'], 'value': [2, 3, 4]}) df['date'] = pd.to_datetime(df['date'], format="%Y-%d-%m %H:%M:%S") df
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
**Exercise :** Check the Pandas documentation and create a dataframe with a columns with dates and try different datetypes. Access date elements dt. accessor :The dt. accessor is an object that allows to access the different data and time elements in a datatime object.https://pandas.pydata.org/docs/reference/api/pandas...
df['date_only'] = df['date'].dt.date df['time_only'] = df['date'].dt.time df['hour_only'] = df['date'].dt.hour df
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Importing datasetshttps://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.read_csv.html
df = pd.read_csv("https://raw.githubusercontent.com/rakelup/EPICLIN2021/master/diabetes.csv", sep=",",error_bad_lines=False) df.head()
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Data overview
# Data overview print ('Rows : ', df.shape[0]) print ('Coloumns : ', df.shape[1]) print ('\nFeatures : \n', df.columns.tolist()) print ('\nNumber of Missing values: ', df.isnull().sum().values.sum()) print ('\nNumber of unique values : \n', df.nunique()) df.describe() df.columns
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Cleaning data in a dataframe: 1. Dealing with missing values2. Data in wrong format3. Wrong data4. Duplicates Dealing with missing values : Handling missing values is an essential part of data cleaning and preparation process since almost all data in real life comes with some missing values. Check for missing values
df.info() df.isnull().sum()
<class 'pandas.core.frame.DataFrame'> RangeIndex: 768 entries, 0 to 767 Data columns (total 9 columns): # Column Non-Null Count Dtype --- ------ -------------- ----- 0 Pregnancies 768 non-null int64 1 Glucose 768 non-null int6...
Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Let's create a daframe with missing values.
df2 = df df2.Glucose.replace(99, np.nan, inplace=True) df2.BloodPressure.replace(74, np.nan, inplace=True) print ('\nNumber of Missing values: ', df2.isnull().sum()) print ('\nTotal number of missing values : ', df2.isnull().sum().values.sum())
Valeurs manquantes: Pregnancies 0 Glucose 17 BloodPressure 52 SkinThickness 0 Insulin 0 BMI 0 DiabetesPedigreeFunction 0 Age 0 Outcome 0 dtype: int64 Vale...
Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
First strategy : Removing the whole row that contains a missing value
# Removing the whole row df3 = df2.dropna() print ('\nValeurs manquantes: ', df3.isnull().sum()) print ('\nValeurs manquantes total: ', df3.isnull().sum().values.sum()) ##Replace the missing values df2.Glucose.replace(np.nan, df['Glucose'].median(), inplace=True) df2.BloodPressure.replace(np.nan, df['BloodPressur...
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Sorting the datahttps://pandas.pydata.org/docs/reference/api/pandas.DataFrame.sort_values.html
#Trier les données b = df.sort_values('Pregnancies') b.head()
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
**Exercise :** Sort the data in descending order according to the insulin level and store the data in a new Data frame. How to store the data in the same dataframe? Subseting the data
df[df['BloodPressure'] >70].count() # Filtrage par valeur df_court = df[['Insulin','Glucose']] df_court.drop('Insulin', inplace= True, axis = 1) df_court.head()
/usr/local/lib/python3.7/dist-packages/pandas/core/frame.py:4174: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy errors=errors,
Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
Statistics applied to dataframesDataFrame.aggregate(func=None, axis=0, *args, **kwargs)Aggregate using one or more operations over the specified axis.https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.aggregate.html
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Apache-2.0
Introduction_to_Pandas.ipynb
Jokos-git/Covid19VaccineAesiDiagnostics
We're going to reate a convolutional neural network that trains to 100% accuracy on these images download below and which cancels training upon hitting training accuracy of >.999
DESIRED_ACCURACY = 0.999 class StopTrainingCallback(tf.keras.callbacks.Callback): def on_epoch_end(self, epoch, logs=None): if logs.get('acc') >= DESIRED_ACCURACY: print(f'\nReached {DESIRED_ACCURACY} accuracy so canceling training!') self.model.stop_training = True model = tf.keras.models.Sequent...
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MIT
Course 1 - Introduction to TensorFlow for AI, ML and DL/Week 4 - Using Real-world Images/Exercise4-Question.ipynb
dksifoua/TensorFlow-in-Practice
语义分割和数据集在前几节讨论的目标检测问题中,我们一直使用方形边界框来标注和预测图像中的目标。本节将探讨语义分割(semantic segmentation)问题,它关注如何将图像分割成属于不同语义类别的区域。值得一提的是,这些语义区域的标注和预测都是像素级的。图9.10展示了语义分割中图像有关狗、猫和背景的标签。可以看到,跟目标检测相比,语义分割标注的像素级的边框显然更加精细。![语义分割中图像有关狗、猫和背景的标签。](../img/segmentation.svg) 图像分割和实例分割计算机视觉领域还有两个和语义分割相似的重要问题:图像分割(image segmentation)和实例分割(instance segmenta...
%matplotlib inline import d2lzh as d2l from mxnet import gluon, image, nd from mxnet.gluon import data as gdata, utils as gutils import os import sys import tarfile
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
我们下载这个数据集的压缩包到`../data`路径下。压缩包大小是2GB,下载需要一定时间。解压之后的数据集将会放置在`../data/VOCdevkit/VOC2012`路径下。
# 本函数已保存在d2lzh包中方便以后使用 def download_voc_pascal(data_dir='../data'): voc_dir = os.path.join(data_dir, 'VOCdevkit/VOC2012') url = ('http://host.robots.ox.ac.uk/pascal/VOC/voc2012' '/VOCtrainval_11-May-2012.tar') sha1 = '4e443f8a2eca6b1dac8a6c57641b67dd40621a49' fname = gutils.download(url, data...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
进入`../data/VOCdevkit/VOC2012`路径后,我们可以获取数据集的不同组成部分。其中`ImageSets/Segmentation`路径包含了指定训练和测试样本的文本文件,而`JPEGImages`和`SegmentationClass`路径下分别包含了样本的输入图像和标签。这里的标签也是图像格式,其尺寸和它所标注的输入图像的尺寸相同。标签中颜色相同的像素属于同一个语义类别。下面定义`read_voc_images`函数将输入图像和标签全部读进内存。
# 本函数已保存在d2lzh包中方便以后使用 def read_voc_images(root=voc_dir, is_train=True): txt_fname = '%s/ImageSets/Segmentation/%s' % ( root, 'train.txt' if is_train else 'val.txt') with open(txt_fname, 'r') as f: images = f.read().split() features, labels = [None] * len(images), [None] * len(images) fo...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
我们画出前五张输入图像和它们的标签。在标签图像中,白色和黑色分别代表边框和背景,而其他不同的颜色则对应不同的类别。
n = 5 imgs = train_features[0:n] + train_labels[0:n] d2l.show_images(imgs, 2, n);
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
接下来,我们列出标签中每个RGB颜色的值及其标注的类别。
# 该常量已保存在d2lzh包中方便以后使用 VOC_COLORMAP = [[0, 0, 0], [128, 0, 0], [0, 128, 0], [128, 128, 0], [0, 0, 128], [128, 0, 128], [0, 128, 128], [128, 128, 128], [64, 0, 0], [192, 0, 0], [64, 128, 0], [192, 128, 0], [64, 0, 128], [192, 0, 128], [64, 128, 128], [192, 128, 128], ...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
有了上面定义的两个常量以后,我们可以很容易地查找标签中每个像素的类别索引。
colormap2label = nd.zeros(256 ** 3) for i, colormap in enumerate(VOC_COLORMAP): colormap2label[(colormap[0] * 256 + colormap[1]) * 256 + colormap[2]] = i # 本函数已保存在d2lzh包中方便以后使用 def voc_label_indices(colormap, colormap2label): colormap = colormap.astype('int32') idx = ((colormap[:, :, 0] * 256 + colormap[:,...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
例如,第一张样本图像中飞机头部区域的类别索引为1,而背景全是0。
y = voc_label_indices(train_labels[0], colormap2label) y[105:115, 130:140], VOC_CLASSES[1]
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
预处理数据在之前的章节中,我们通过缩放图像使其符合模型的输入形状。然而在语义分割里,这样做会需要将预测的像素类别重新映射回原始尺寸的输入图像。这样的映射难以做到精确,尤其在不同语义的分割区域。为了避免这个问题,我们将图像裁剪成固定尺寸而不是缩放。具体来说,我们使用图像增广里的随机裁剪,并对输入图像和标签裁剪相同区域。
# 本函数已保存在d2lzh包中方便以后使用 def voc_rand_crop(feature, label, height, width): feature, rect = image.random_crop(feature, (width, height)) label = image.fixed_crop(label, *rect) return feature, label imgs = [] for _ in range(n): imgs += voc_rand_crop(train_features[0], train_labels[0], 200, 300) d2l.show_ima...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
自定义语义分割数据集类我们通过继承Gluon提供的`Dataset`类自定义了一个语义分割数据集类`VOCSegDataset`。通过实现`__getitem__`函数,我们可以任意访问数据集中索引为`idx`的输入图像及其每个像素的类别索引。由于数据集中有些图像的尺寸可能小于随机裁剪所指定的输出尺寸,这些样本需要通过自定义的`filter`函数所移除。此外,我们还定义了`normalize_image`函数,从而对输入图像的RGB三个通道的值分别做标准化。
# 本类已保存在d2lzh包中方便以后使用 class VOCSegDataset(gdata.Dataset): def __init__(self, is_train, crop_size, voc_dir, colormap2label): self.rgb_mean = nd.array([0.485, 0.456, 0.406]) self.rgb_std = nd.array([0.229, 0.224, 0.225]) self.crop_size = crop_size features, labels = read_voc_images(roo...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
读取数据集我们通过自定义的`VOCSegDataset`类来分别创建训练集和测试集的实例。假设我们指定随机裁剪的输出图像的形状为$320\times 480$。下面我们可以查看训练集和测试集所保留的样本个数。
crop_size = (320, 480) voc_train = VOCSegDataset(True, crop_size, voc_dir, colormap2label) voc_test = VOCSegDataset(False, crop_size, voc_dir, colormap2label)
read 1114 examples
Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
设批量大小为64,分别定义训练集和测试集的迭代器。
batch_size = 64 num_workers = 0 if sys.platform.startswith('win32') else 4 train_iter = gdata.DataLoader(voc_train, batch_size, shuffle=True, last_batch='discard', num_workers=num_workers) test_iter = gdata.DataLoader(voc_test, batch_size, last_batch='discard', ...
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Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
打印第一个小批量的形状。不同于图像分类和目标识别,这里的标签是一个三维的数组。
for X, Y in train_iter: print(X.shape) print(Y.shape) break
(64, 3, 320, 480) (64, 320, 480)
Apache-2.0
chapter_computer-vision/semantic-segmentation-and-dataset.ipynb
femj007/d2l-zh
Questões1. **A idade determinou suas chances de sobrevivência?**2. **Qual o tamanho de uma família de sobreviventes?**3. **Baseado nas classes, comparar e identificar as relações entre elas?** Análise dos Dados Descrição dos dados- **survival:** Survival (0 = No; 1 = Yes)- **pclass:** Passenger Class (1 = 1st; 2 = 2...
# Matlib inline %matplotlib inline # Bibliotecas import pandas as pd import numpy as np import matplotlib.pyplot as plt import seaborn as sns # Lê o csv e cria o dataframe titanic_data = pd.read_csv('titanic-data-6.csv') # Print dos primeiros registros para identificação de dados titanic_data.head() # Print dos ultim...
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
**Nota:** Alguns valores para Age são NaN, enquanto os valores de ticket e cabine são alfanuméricos e também valores ausentes com NaN. Com isso, não serão necessários dados do ticket ou da cabine. Limpeza dos dadosDesde a descrição dos dados e perguntas até a resposta, nota-se que algumas colunas não serão utilizadas ...
# Identifique e remova quaisquer entradas duplicadas titanic_duplicados = titanic_data.duplicated() sum(titanic_duplicados)
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
2 - Remova as colunas desnecessáriasColunas do passo **limpeza de dados** removidas
# Cria um novo dataset sem as colunas to_drop = [ 'PassengerId', 'Name', 'Ticket', 'Cabin', 'Fare', 'Embarked' ] def clean_data(to_drop): """ Função clean_data. Argumentos: to_drop: lista das colunas que deseja remover. Retorna: Retorna um...
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
3 - Corrigir problemas de formato e de dados
# Soma de valores faltantes titanic_dados_limpos.isnull().sum() # Review da coluna Age para verificar dados NaN coluna_idade_faltante = pd.isnull(titanic_dados_limpos['Age']) titanic_dados_limpos[coluna_idade_faltante].head() # Visualização dos tipos de dados titanic_dados_limpos.info()
<class 'pandas.core.frame.DataFrame'> RangeIndex: 891 entries, 0 to 890 Data columns (total 6 columns): Survived 891 non-null int64 Pclass 891 non-null int64 Sex 891 non-null object Age 714 non-null float64 SibSp 891 non-null int64 Parch 891 non-null int64 dtypes: float64(1), int64(4...
MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
Pode-se observar que a coluna **Age** irá implicar nas perguntas, então, graficamente iremos tratar as idades nulas como 0. Exploração e Visualização dos Dados
# Descrição dos dados titanic_dados_limpos.describe()
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
Questão 1A idade determinou suas chances de sobrevivência?
# Primeiro, identifica-se o número total de dados Age nulos idade_feminino_vazio = titanic_dados_limpos[coluna_idade_faltante]['Sex'] == 'female' idade_masculino_vazio = titanic_dados_limpos[coluna_idade_faltante]['Sex'] == 'male' print ("Total de nulos no sexo feminino".format(idade_feminino_vazio.sum())) print ("Tot...
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
Baseado nos dados visíveis acima:- Pode-se concluir que a **idade não é um fator deciviso para a taxa de sobrevivência** Questão 2Qual o tamanho de uma família de sobreviventes?
# add Tamanho da Familia em nossa tabela titanic_data_age_limpo['FamilySize'] = titanic_data_age_limpo['SibSp'] + titanic_data_age_limpo['Parch'] # Agrupamos pelo Tamanho ordenando pela coluna Survived titanic_data_age_limpo[['FamilySize', 'Survived']].groupby(['FamilySize'], as_index=False).mean().sort_values(by='Surv...
/home/allan/anaconda3/lib/python3.6/site-packages/ipykernel_launcher.py:2: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#...
MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
Após análise dos dados, observa-se que as famílias com **1 a 3 membros** tem uma taxa maior de sobrevivência que as famílias com **4 a 7 membros** Questão 3Baseado nas classes, comparar e identificar as relações entre elas?
# Gráfico linar com idade x sobreviviu x classe g = sns.lmplot('Age','Survived',hue='Pclass',data=titanic_data_age_limpo,palette='winter') # Acessa a figura fig = g.fig # Add um título fig.suptitle("Classe x Sobrevivência")
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MIT
TitanicUdacity.ipynb
AllanKDeveloper/titanic_data
Feature Selection Tutorial
import matplotlib import matplotlib.pyplot as plt import numpy as np from sklearn.feature_selection import SelectFromModel from sklearn.linear_model import Lasso, LinearRegression, lasso_path, lasso_stability_path, lars_path import warnings from scipy import linalg from sklearn.linear_model import (RandomizedLass...
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MIT
2016/tutorial_final/75/Feature Selection Tutorial.ipynb
zeromtmu/practicaldatascience.github.io