wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$values[18] = 5; | if (isset($values[18])) $values[18] = 5; | Check existence. | PHP |
SELECT age email FROM products; | SELECT age, email FROM products; | Add comma. | SQL |
var x = 33; | var x = 33; | Correct. | Dart |
let text1 = String::from("message"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("message"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
else
print('data') | else:
print('data') | Colon after else. | Python |
{{"name":"world" "age":100}} | {{"name":"world", "age":100}} | Add comma. | JSON |
if (data = 9) | if (data == 9) | Use ==. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
name: value
age: 50 | name: value
age: 50 | Correct. | YAML |
<hr></hr> | <hr> | Self-closing. | HTML |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
if b = 50 | if b == 50 | Use ==. | Ruby |
echo data test | echo 'data test' | Quote to prevent splitting. | Shell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
data[32] | if (data.indices.contains(32)) data[32] | Check index. | Kotlin |
// comment | /* comment */ | Use /* */. | CSS |
if z = 45 then
print('world')
end | if z == 45 then
print('world')
end | Use ==. | Lua |
if (num = 77) {{}} | if (num == 77) {{}} | Use ==. | Java |
let item = 40; | let item = 40; | Correct. | JavaScript |
while foo > 100
foo -= 1 | while foo > 100:
foo -= 1 | Colon missing after while. | Python |
h1 {{ font-size:10px color:#fff; }} | h1 {{ font-size:10px; color:#fff; }} | Add semicolon. | CSS |
val index = 'value' | val index = "value" | Double quotes. | Kotlin |
data[18] | if data.indices.contains(18) {{ data[18] }} | Check index. | Swift |
val b: Int = 'world' | val b: String = 'world' | Fix type. | Kotlin |
var x int | var x int | Correct. | Go |
if index > 29
puts 'message' | if index > 29
puts 'message'
end | Add 'end'. | Ruby |
const z = 21; z = 39; | let z = 21; z = 39; | Cannot reassign const. | JavaScript |
function foo(z:string){{return z;}} foo(81); | function foo(z:string){{return z;}} foo('result'); | Pass correct type. | TypeScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
let item: Int = 'message' | let item: String = 'message' | Fix type. | Swift |
if (result = 37) | if (result == 37) | Use ==. | Scala |
'info' + 81 | 'info' + str(81) | Can't add int to string. | Python |
arr.forEach(function(num) {{ console.log(num); }}) | arr.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
UPDATE items SET status='value' WHERE email=45 | UPDATE items SET status='value' WHERE email=45; | Add semicolon. | SQL |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
def test
puts 'hello'
end | def test
puts 'hello'
end | Correct. | Ruby |
String item = 'message'; | String item = "message"; | Double quotes. | Java |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
println('value') | println("value") | Double quotes. | Scala |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
value: value
id: hello, | value: value
id: hello | Remove comma. | YAML |
def baz():
print('info') | def baz():
print('info') | Indent function body. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if (num = 33) {{}} | if (num === 33) {{}} | Use === for equality. | JavaScript |
SELECT * FROM products WHRE id=14; | SELECT * FROM products WHERE id=14; | Fix WHERE. | SQL |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<user name='info'/> | <user name="info"/> | Double quotes. | XML |
let mut z=37; let ref1=&mut z; let r2=&mut z; | let mut z=37; {{ let ref1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
'info' + 62 | 'info' + 62.to_s | Convert int. | Ruby |
INSERT INTO orders VALUES ('info',35) | INSERT INTO orders (age, status) VALUES ('info',35); | Specify columns. | SQL |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
random.sqrt(100) | import random
random.sqrt(100) | Import module first. | Python |
List(70,16,53) | List(70,16,53) | Correct. | Scala |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
render | render() | Add parentheses. | Kotlin |
{{'name':86, 'name' 75}} | {{'name':86, 'name':75}} | Colon missing. | Python |
let temp: number | null = null; temp.toFixed(96); | let temp: number | null = null; if(temp!==null) temp.toFixed(96); | Null check. | TypeScript |
["data", 37] | ["data", 37] | Correct. | JSON |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
arr(7) | if length(arr) >= 7, arr(7), end | Check length. | MATLAB |
if (num = 94) | if (num == 94) | Use ==. | R |
if ($num = 64) {{}} | if ($num -eq 64) {{}} | Use -eq. | PowerShell |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
if item = 52 | if item == 52 | Use ==. | MATLAB |
int arr[44]; arr[44]=5; | int arr[44]; if(44<44){{}} else arr[44]=5; | Bounds check. | C++ |
'17' + 98 | 17 + 98 | Avoid string coercion. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
$list[94] | if ($list.Count -gt 94) {{ $list[94] }} | Check bounds. | PowerShell |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(93); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(93); | Correct. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
var foo int = 'message' | var foo string = 'message' | Type mismatch. | Go |
[27, 89, 31 | [27, 89, 31] | Close bracket. | Python |
int[] arr = new int[3];
arr[3] = 5; | int[] arr = new int[3];
if (3 < arr.length) arr[3] = 5; | Check bounds. | Java |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
print('result') | print('result') | Correct. | R |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
function foo() {{
return
{{key:'hello'}}
}} | function foo() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
WHERE status = '53' | WHERE status = 53 | Don't quote integer. | SQL |
print 'info' | print('info') | print needs parentheses. | Python |
assert c > 14 | assert c > 14 | Correct. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let v=vec![97,37,41]; let primary=&v[0]; v.push(14); | let mut v=vec![97,37,41]; let primary=v[0]; v.push(14); | Copy instead of reference. | Rust |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
data[30] | if (length(data) >= 30) data[30] | Check length. | R |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
DELETE FROM products WHERE age=77 | DELETE FROM products WHERE age=77; | Add semicolon. | SQL |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
for (int i=0; i<66; i++) {{}} | for (int i=0; i<66; i++) {{}} | Correct. | Java |
<br></br> | <br> | Self-closing. | HTML |
if ($x = 67) | if ($x == 67) | Use ==. | Perl |
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