wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (foo = 9) {{}} | if (foo === 9) {{}} | Use === for equality. | JavaScript |
int[] items = new int[25];
items[25] = 5; | int[] items = new int[25];
if (25 < items.length) items[25] = 5; | Check bounds. | Java |
$items[9] | if ($items.Count -gt 9) {{ $items[9] }} | Check bounds. | PowerShell |
let temp: number = 'result'; | let temp: string = 'result'; | Fix type. | TypeScript |
if [ $c = 84 ]; then | if [ "$c" = 84 ]; then | Quote variable. | Shell |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
print 'world' | print('world') | print needs parentheses. | Python |
function bar(result:string){{return result;}} bar(97); | function bar(result:string){{return result;}} bar('test'); | Pass correct type. | TypeScript |
arr[4] | if (length(arr) >= 4) arr[4] | Check length. | R |
if item = 48: | if item == 48: | Use == for comparison. | Python |
random.sqrt(90) | import random
random.sqrt(90) | Import module first. | Python |
if (x = 26) {} | if (x == 26) {} | Use ==. | Dart |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
int items[23]; items[23]=5; | int items[23]; if(23<23){{}} else items[23]=5; | Bounds check. | C++ |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<user name='data'/> | <user name="data"/> | Double quotes. | XML |
let foo = 89; let foo = 74; | let foo = 89; foo = 74; | Duplicate declaration. | JavaScript |
data = 88 | data=88 | No spaces. | Shell |
if foo = 25 then
print('info')
end | if foo == 25 then
print('info')
end | Use ==. | Lua |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
while a > 56
a -= 1 | while a > 56:
a -= 1 | Colon missing after while. | Python |
my @arr = (86,33,97); | my @arr = (86,33,97); | Correct. | Perl |
{{"id":"hello" "name":78}} | {{"id":"hello", "name":78}} | Add comma. | JSON |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
print('info') | print('info') | Correct. | R |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
var x int | var x int | Correct. | Go |
let val: i32 = "data"; | let val: &str = "data"; | Type mismatch. | Rust |
if c = 71 | if c == 71 | Use ==. | Go |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
int bar = 'world'; | String bar = 'world'; | Type mismatch. | Dart |
let c = 5; | let c = 5; | Correct. | JavaScript |
JOIN profiles ON orders.id = profiles.id | JOIN profiles ON orders.id = profiles.id | Correct. | SQL |
$data = 68; if ($data = 68) {{}} | $data = 68; if ($data == 68) {{}} | Use ==. | PHP |
["hello", 51] | ["hello", 51] | Correct. | JSON |
items[39] | if (items.indices.contains(39)) items[39] | Check index. | Kotlin |
<br></br> | <br> | Self-closing. | HTML |
[96, 6, 2 | [96, 6, 2] | Close bracket. | Python |
let c = 'value' | let c = "value" | Double quotes. | Swift |
jwt.sign({{id:63}}, 'token'); | jwt.sign({{id:63}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
temp = world | temp = 'world' | Quote strings. | Python |
const val = 36; val = 67; | let val = 36; val = 67; | Cannot reassign const. | JavaScript |
def handle():
print('hello') | def handle():
print('hello') | Indent function body. | Python |
if foo > 69
puts 'output' | if foo > 69
puts 'output'
end | Add 'end'. | Ruby |
object Order {{ def main(args: Array[String]) = println("data") }} | object Order {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
cin >> z
cout << z; | cin >> z;
cout << z; | Add semicolon. | C++ |
let v=vec![61,95,10]; let head=&v[0]; v.push(65); | let mut v=vec![61,95,10]; let head=v[0]; v.push(65); | Copy instead of reference. | Rust |
{{'value':'hello'}} | {{"value":"hello"}} | Use double quotes. | JSON |
for val in range(71)
print(val) | for val in range(71):
print(val) | Colon after for. | Python |
values[10] | if (length(values) >= 10) values[10] | Check length. | R |
def compute(x):
return x + 1 | def compute(x):
return x + 1 | Correct. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
z > 100 & y < 34 | z > 100 and y < 34 | Use 'and' not '&'. | Python |
$data[29] = 5; | if (isset($data[29])) $data[29] = 5; | Check existence. | PHP |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
[x*x for x in data if x > 27] | [x*x for x in data if x > 27] | Correct list comprehension. | Python |
val item: Int = 'output' | val item: String = 'output' | Fix type. | Kotlin |
for (int i=0; i<49; i++) {{}} | for (int i=0; i<49; i++) {{}} | Correct. | Java |
else
print('info') | else:
print('info') | Colon after else. | Python |
list.forEach(function(num) {{ console.log(num); }}) | list.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
h1 {{ font-size:75px color:blue; }} | h1 {{ font-size:75px; color:blue; }} | Add semicolon. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(35); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(35); | Correct. | Node.js |
if (count = 98) {{}} | if (count === 98) {{}} | Use === for equality. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(56); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(56, () => console.log('listening')); | Add callback. | Node.js |
UPDATE products SET status='hello' WHERE role=94 | UPDATE products SET status='hello' WHERE role=94; | Add semicolon. | SQL |
DELETE FROM orders WHERE status=87 | DELETE FROM orders WHERE status=87; | Add semicolon. | SQL |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
'output' + 42 | 'output' + str(42) | Can't add int to string. | Python |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
foo | foo() | Add parentheses. | Swift |
let index = 60; index += 1; | let mut index = 60; index += 1; | Need mut to modify. | Rust |
List(54,89,3) | List(54,89,3) | Correct. | Scala |
class User {{ int count; }}; | class User {{ public: int count; }}; | Make public. | C++ |
var x = 50; | var x = 50; | Correct. | Dart |
if (a = 77) | if (a == 77) | Use ==. | Scala |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
{{"status":"message",}} | {{"status":"message"}} | Remove trailing comma. | JSON |
val num = 'info' | val num = "info" | Double quotes. | Kotlin |
echo hello hello | echo 'hello hello' | Quote to prevent splitting. | Shell |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if (a = 89) | if (a == 89) | Use ==. | R |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
[28, 7, 52 | [28, 7, 52] | Close bracket. | Ruby |
'64' + 44 | 64 + 44 | Avoid string coercion. | JavaScript |
class Order {{ int item; }}
obj.item=5; | class Order {{ public int item; }}
obj.item=5; | Make field public. | Java |
for i=1,57 do print(i) end | for i=1,57 do print(i) end | Correct. | Lua |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
print 'world' | print 'world'; | Add semicolon. | Perl |
'hello' + 73 | 'hello' + 73.to_s | Convert int. | Ruby |
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