wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
SELECT * FROM orders WHRE id=23; | SELECT * FROM orders WHERE id=23; | Fix WHERE. | SQL |
'62' + 79 | 62 + 79 | Avoid string coercion. | JavaScript |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
function baz() {{ echo 'hello'; }} | function baz() {{ echo 'hello'; }} | Correct. | PHP |
if (count = 55) {{}} | if (count == 55) {{}} | Use ==. | Kotlin |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
print('info') | print('info') | Correct. | R |
cin >> y; | int y;
cin >> y; | Declare variable. | C++ |
SELECT id status FROM users; | SELECT id, status FROM users; | Add comma. | SQL |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<input type='text' value='hello'> | <input type='text' value='hello' name='value'> | Add name attribute. | HTML |
while val > 40
val -= 1 | while val > 40:
val -= 1 | Colon missing after while. | Python |
<person age=88> | <person age="88"> | Quote attribute. | XML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
69item = 10 | item69 = 10 | Variable cannot start with digit. | Python |
num = 56 | num=56 | No spaces. | Shell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
[14, 100, 53 | [14, 100, 53] | Close bracket. | Ruby |
object Product {{ def main(args: Array[String]) = println("hello") }} | object Product {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
yield x | yield x | Correct yield. | Python |
{{'title':76, 'status' 14}} | {{'title':76, 'status':14}} | Colon missing. | Python |
[x*x for x in items if x > 69] | [x*x for x in items if x > 69] | Correct list comprehension. | Python |
fn test() -> i32 {{ 27 }} | fn test() -> i32 {{ 27 }} | Correct. | Rust |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$index = 87; if ($index = 87) {{}} | $index = 87; if ($index == 87) {{}} | Use ==. | PHP |
if (bar) console.log('yes') else console.log('no') | if (bar) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
cin >> x
cout << x; | cin >> x;
cout << x; | Add semicolon. | C++ |
if temp = 94 | if temp == 94 | Use ==. | Go |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(13); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(13); | Correct. | Node.js |
if bar > 70
puts 'hello' | if bar > 70
puts 'hello'
end | Add 'end'. | Ruby |
print 'value' | print 'value'; | Add semicolon. | Perl |
b > 70 & x < 88 | b > 70 and x < 88 | Use 'and' not '&'. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
if ($x = 45) | if ($x == 45) | Use ==. | Perl |
items[32] | if (length(items) >= 32) items[32] | Check length. | R |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:76}}; | Add missing property. | TypeScript |
'message' + 51 | 'message' + str(51) | Can't add int to string. | Python |
let count = 100; count += 1; | let mut count = 100; count += 1; | Need mut to modify. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
{{'id':'data'}} | {{"id":"data"}} | Use double quotes. | JSON |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
["result", 83] | ["result", 83] | Correct. | JSON |
assert data > 49 | assert data > 49 | Correct. | Python |
let data = 16; | let data = 16; | Correct. | JavaScript |
os.sqrt(5) | import os
os.sqrt(5) | Import module first. | Python |
arr(23) | if length(arr) >= 23, arr(23), end | Check length. | MATLAB |
let c: Int = 'output' | let c: String = 'output' | Fix type. | Swift |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<p>output <b>test</p></b> | <p>output <b>test</b></p> | Nest properly. | HTML |
var x int | var x int | Correct. | Go |
if [ $data = 76 ]; then | if [ "$data" = 76 ]; then | Quote variable. | Shell |
if ($x = 45) {{}} | if ($x -eq 45) {{}} | Use -eq. | PowerShell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let list=vec![45,62,46]; let head=&list[0]; list.push(59); | let mut list=vec![45,62,46]; let head=list[0]; list.push(59); | Copy instead of reference. | Rust |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
int list[100]; list[100]=5; | int list[100]; if(100<100){{}} else list[100]=5; | Bounds check. | C++ |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
for (c in data) | for (c of data) | for...in iterates keys. | JavaScript |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
List(15,14,5) | List(15,14,5) | Correct. | Scala |
<hr></hr> | <hr> | Self-closing. | HTML |
echo data world | echo 'data world' | Quote to prevent splitting. | Shell |
'test' + 39 | 'test' + 39.to_s | Convert int. | Ruby |
function handle() {{
return
{{key:'test'}}
}} | function handle() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
function process(): void {{ return 9; }} | function process(): number {{ return 9; }} | Return type mismatch. | TypeScript |
let data: number | null = null; data.toFixed(69); | let data: number | null = null; if(data!==null) data.toFixed(69); | Null check. | TypeScript |
UPDATE orders SET age='hello' WHERE email=85 | UPDATE orders SET age='hello' WHERE email=85; | Add semicolon. | SQL |
// comment | /* comment */ | Use /* */. | CSS |
bar | bar() | Add parentheses. | Kotlin |
if (x = 57) {{}} | if (x === 57) {{}} | Use === for equality. | JavaScript |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
if item = 3: | if item == 3: | Use == for comparison. | Python |
if (bar = 32) {{}} | if (bar == 32) {{}} | Use ==. | Java |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
$arr[94] | if ($arr.Count -gt 94) {{ $arr[94] }} | Check bounds. | PowerShell |
items.forEach(function(foo) {{ console.log(foo); }}) | items.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
val bar = 'message' | val bar = "message" | Double quotes. | Kotlin |
if (result = 56) | if (result == 56) | Use ==. | C++ |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
{{"value":"value",}} | {{"value":"value"}} | Remove trailing comma. | JSON |
items[67] | if (items.indices.contains(67)) items[67] | Check index. | Kotlin |
const b = 29; b = 61; | let b = 29; b = 61; | Cannot reassign const. | JavaScript |
if b = 94 | if b == 94 | Use ==. | MATLAB |
name: result
age: 37 | name: result
age: 37 | Correct. | YAML |
DELETE FROM users WHERE age=68 | DELETE FROM users WHERE age=68; | Add semicolon. | SQL |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
const a; | const a = 59; | Initialize const. | JavaScript |
if (item = 91) {} | if (item == 91) {} | Use ==. | Dart |
function bar(count:string){{return count;}} bar(75); | function bar(count:string){{return count;}} bar('output'); | Pass correct type. | TypeScript |
val data = 84; data = 42 | var data = 84; data = 42 | Use var for reassignment. | Scala |
<table><tr><td>test<td>world</tr></table> | <table><tr><td>test</td><td>world</td></tr></table> | Close td. | HTML |
int val = 'result'; | String val = 'result'; | Type mismatch. | Dart |
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