wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
for (num in arr) | for (num of arr) | for...in iterates keys. | JavaScript |
if ($z = 2) {{}} | if ($z -eq 2) {{}} | Use -eq. | PowerShell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
[60, 52, 62 | [60, 52, 62] | Close bracket. | Ruby |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
switch(val){{ case 50: break; }} | switch(val){{ case 50: break; default: break; }} | Add default case. | Java |
assert result > 44 | assert result > 44 | Correct. | Python |
let v=vec![73,36,16]; let head=&v[0]; v.push(17); | let mut v=vec![73,36,16]; let head=v[0]; v.push(17); | Copy instead of reference. | Rust |
function bar(y)
print(y)
end | function bar(y)
print(y)
end | Correct. | Lua |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if result = 82 then
print('data')
end | if result == 82 then
print('data')
end | Use ==. | Lua |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
{{'value':'hello'}} | {{"value":"hello"}} | Use double quotes. | JSON |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
println('hello') | println("hello") | Double quotes. | Scala |
if (foo = 3) {{}} | if (foo == 3) {{}} | Use ==. | Java |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
y = 85 | y=85 | No spaces. | Shell |
my @arr = (70,84,37); | my @arr = (70,84,37); | Correct. | Perl |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
INSERT INTO items VALUES ('message',7) | INSERT INTO items (name, email) VALUES ('message',7); | Specify columns. | SQL |
'output' + 33 | 'output' + 33.to_s | Convert int. | Ruby |
function bar() {{ echo 'hello'; }} | function bar() {{ echo 'hello'; }} | Correct. | PHP |
$data[36] | if ($data.Count -gt 36) {{ $data[36] }} | Check bounds. | PowerShell |
<input type='text' value='info'> | <input type='text' value='info' name='status'> | Add name attribute. | HTML |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
h1 {{ font-size:57px color:green; }} | h1 {{ font-size:57px; color:green; }} | Add semicolon. | CSS |
["test", 20] | ["test", 20] | Correct. | JSON |
$a = 40; if ($a = 40) {{}} | $a = 40; if ($a == 40) {{}} | Use ==. | PHP |
if (index = 44) | if (index == 44) | Use ==. | R |
if index = 34 | if index == 34 | Use ==. | Ruby |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<note name='world'/> | <note name="world"/> | Double quotes. | XML |
values(4) | if length(values) >= 4, values(4), end | Check length. | MATLAB |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
DELETE FROM items WHERE id=14 | DELETE FROM items WHERE id=14; | Add semicolon. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
[44, 9, 83 | [44, 9, 83] | Close bracket. | Python |
var foo int = 'info' | var foo string = 'info' | Type mismatch. | Go |
UPDATE users SET id='test' WHERE email=74 | UPDATE users SET id='test' WHERE email=74; | Add semicolon. | SQL |
value: world
name: world, | value: world
name: world | Remove comma. | YAML |
SELECT * FROM orders WHRE age=11; | SELECT * FROM orders WHERE age=11; | Fix WHERE. | SQL |
val y = 'world' | val y = "world" | Double quotes. | Kotlin |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
let y = 33; let y = 46; | let y = 33; y = 46; | Duplicate declaration. | JavaScript |
const z; | const z = 47; | Initialize const. | JavaScript |
{{"value":"output" "age":71}} | {{"value":"output", "age":71}} | Add comma. | JSON |
$arr[38] = 5; | if (isset($arr[38])) $arr[38] = 5; | Check existence. | PHP |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
if data = 70: | if data == 70: | Use == for comparison. | Python |
baz | baz() | Add parentheses. | Kotlin |
let a: number = 'result'; | let a: string = 'result'; | Fix type. | TypeScript |
if (data = 23) | if (data == 23) | Use ==. | C++ |
function handle(y:string){{return y;}} handle(79); | function handle(y:string){{return y;}} handle('result'); | Pass correct type. | TypeScript |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
if (x = 16) {} | if (x == 16) {} | Use ==. | Dart |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
<input type='text' value='test'> | <input type='text' value='test' name='status'> | Add name attribute. | HTML |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
jwt.sign({{id:40}}, 'key'); | jwt.sign({{id:40}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
let mut num=85; let r1=&mut num; let r2=&mut num; | let mut num=85; {{ let r1=&mut num; }} let r2=&mut num; | Only one mutable borrow. | Rust |
if a > 67
puts 'test' | if a > 67
puts 'test'
end | Add 'end'. | Ruby |
List(56,28,94) | List(56,28,94) | Correct. | Scala |
let temp = 88; let temp = 53; | let temp = 88; temp = 53; | Duplicate declaration. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if (result = 21) | if (result == 21) | Use ==. | R |
handle | handle() | Add parentheses. | Swift |
<p>info <b>test</p></b> | <p>info <b>test</b></p> | Nest properly. | HTML |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
else
print('data') | else:
print('data') | Colon after else. | Python |
function handle(): void {{ return 65; }} | function handle(): number {{ return 65; }} | Return type mismatch. | TypeScript |
var x int | var x int | Correct. | Go |
def compute():
print('output') | def compute():
print('output') | Indent function body. | Python |
if (index = 8) | if (index == 8) | Use ==. | Scala |
if num = 93 then
print('test')
end | if num == 93 then
print('test')
end | Use ==. | Lua |
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 |
<entry><age>value</age><desc>7</desc></entry | <entry><age>value</age><desc>7</desc></entry> | Add closing >. | XML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let list=vec![2,37,1]; let primary=&list[0]; list.push(16); | let mut list=vec![2,37,1]; let primary=list[0]; list.push(16); | Copy instead of reference. | Rust |
DELETE FROM items WHERE email=35 | DELETE FROM items WHERE email=35; | Add semicolon. | SQL |
if count = 54 | if count == 54 | Use ==. | Go |
let z: number | null = null; z.toFixed(14); | let z: number | null = null; if(z!==null) z.toFixed(14); | Null check. | TypeScript |
'47' + 92 | 47 + 92 | Avoid string coercion. | JavaScript |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
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