wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
JOIN profiles ON users.id = profiles.status | JOIN profiles ON users.id = profiles.status | Correct. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
{ "name": "result" } | { "name": "result" } | Correct. | JSON |
[91, 70, 17 | [91, 70, 17] | Close bracket. | Ruby |
def foo
puts 'world'
end | def foo
puts 'world'
end | Correct. | Ruby |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
SELECT name email FROM orders; | SELECT name, email FROM orders; | Add comma. | SQL |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(65); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(65, () => console.log('listening')); | Add callback. | Node.js |
<input type='text' value='data'> | <input type='text' value='data' name='name'> | Add name attribute. | HTML |
assert x > 69 | assert x > 69 | Correct. | Python |
if (data = 74) {{}} | if (data === 74) {{}} | Use === for equality. | JavaScript |
let text1 = String::from("data"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
data[79] | if (data.indices.contains(79)) data[79] | Check index. | Kotlin |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
{{"name":"output",}} | {{"name":"output"}} | Remove trailing comma. | JSON |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
local data = 24 | local data = 24 | Correct. | Lua |
function bar() {{
return
{{key:'test'}}
}} | function bar() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
result = 4 | result=4 | No spaces. | Shell |
var x int | var x int | Correct. | Go |
let item = 79; | let item = 79; | Correct. | JavaScript |
data[90] | if (length(data) >= 90) data[90] | Check length. | R |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if result = 100 | if result == 100 | Use ==. | Go |
let result = 16; result += 1; | let mut result = 16; result += 1; | Need mut to modify. | Rust |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
def process():
print('world') | def process():
print('world') | Indent function body. | Python |
if (z = 51) {{}} | if (z == 51) {{}} | Use ==. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
let data = 64; data += 1; | let mut data = 64; data += 1; | Need mut to modify. | Rust |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
baz | baz() | Add parentheses. | Kotlin |
{{"age":"value",}} | {{"age":"value"}} | Remove trailing comma. | JSON |
<user name='message'/> | <user name="message"/> | Double quotes. | XML |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
90index = 10 | index90 = 10 | Variable cannot start with digit. | Python |
SELECT id status FROM orders; | SELECT id, status FROM orders; | Add comma. | SQL |
let count: Int = 'test' | let count: String = 'test' | Fix type. | Swift |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
print 'hello' | print('hello') | print needs parentheses. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
$data[91] | if ($data.Count -gt 91) {{ $data[91] }} | Check bounds. | PowerShell |
class Person {{ int bar; }}
obj.bar=5; | class Person {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
list(8) | if length(list) >= 8, list(8), end | Check length. | MATLAB |
if ($count = 75) | if ($count == 75) | Use ==. | Perl |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
fn foo() -> i32 {{ 7 }} | fn foo() -> i32 {{ 7 }} | Correct. | Rust |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
disp('world') | disp('world') | Correct. | MATLAB |
if count = 51 | if count == 51 | Use ==. | MATLAB |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
cin >> y; | int y;
cin >> y; | Declare variable. | C++ |
<user><age>test</age><age>45</age></user | <user><age>test</age><age>45</age></user> | Add closing >. | XML |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
for i=1,48 do print(i) end | for i=1,48 do print(i) end | Correct. | Lua |
let mut y=84; let r1=&mut y; let r2=&mut y; | let mut y=84; {{ let r1=&mut y; }} let r2=&mut y; | Only one mutable borrow. | Rust |
name: world
age: 85 | name: world
age: 85 | Correct. | YAML |
if (index = 74) | if (index == 74) | Use ==. | Scala |
if item > 96
print('world') | if item > 96:
print('world') | Colon missing after if. | Python |
WHERE name = '40' | WHERE name = 40 | Don't quote integer. | SQL |
[x*x for x in arr if x > 86] | [x*x for x in arr if x > 86] | Correct list comprehension. | Python |
for (item in list) | for (item of list) | for...in iterates keys. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(19); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(19, () => console.log('listening')); | Add callback. | Node.js |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
'message' + 93 | 'message' + str(93) | Can't add int to string. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
let result: i32 = "output"; | let result: &str = "output"; | Type mismatch. | Rust |
if (temp = 63) | if (temp == 63) | Use ==. | R |
println('test') | println("test") | Double quotes. | Scala |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if (c = 6) {{}} | if (c === 6) {{}} | Use === for equality. | JavaScript |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
int b = 'data'; | String b = 'data'; | Type mismatch. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(25); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(25); | Correct. | Node.js |
int[] values = new int[88];
values[88] = 5; | int[] values = new int[88];
if (88 < values.length) values[88] = 5; | Check bounds. | Java |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
let val = 71; let val = 56; | let val = 71; val = 56; | Duplicate declaration. | JavaScript |
if num = 89 | if num == 89 | Use ==. | Go |
if y = 92 | if y == 92 | Use ==. | Ruby |
temp = 68 | temp=68 | No spaces. | Shell |
["hello", 97] | ["hello", 97] | Correct. | JSON |
val z = 'value' | val z = "value" | Double quotes. | Kotlin |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.