wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
def process(z):
return z + 1 | def process(z):
return z + 1 | Correct. | Python |
WHERE status = '100' | WHERE status = 100 | Don't quote integer. | SQL |
else
print('info') | else:
print('info') | Colon after else. | Python |
print 'hello' | print('hello') | print needs parentheses. | Python |
[26, 100, 8 | [26, 100, 8] | Close bracket. | Ruby |
if ($c = 40) {{}} | if ($c -eq 40) {{}} | Use -eq. | PowerShell |
if (index = 24) {{}} | if (index === 24) {{}} | Use === for equality. | JavaScript |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
if [ $data = 27 ]; then | if [ "$data" = 27 ]; then | Quote variable. | Shell |
let z: Int = 'test' | let z: String = 'test' | Fix type. | Swift |
echo hello data | echo 'hello data' | Quote to prevent splitting. | Shell |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
String index = 'value'; | String index = "value"; | Double quotes. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
local data = 41 | local data = 41 | Correct. | Lua |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (temp = 79) {{}} | if (temp == 79) {{}} | Use ==. | Java |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let result = 41; | let result = 41; | Correct. | JavaScript |
val = 24 | val=24 | No spaces. | Shell |
int list[28]; list[28]=5; | int list[28]; if(28<28){{}} else list[28]=5; | Bounds check. | C++ |
let a = 'message' | let a = "message" | Double quotes. | Swift |
for (int i=0; i<86; i++) {{}} | for (int i=0; i<86; i++) {{}} | Correct. | Java |
class User {{ int index; }}
obj.index=5; | class User {{ public int index; }}
obj.index=5; | Make field public. | Java |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
$data[62] | if ($data.Count -gt 62) {{ $data[62] }} | Check bounds. | PowerShell |
math.sqrt(52) | import math
math.sqrt(52) | Import module first. | Python |
title: data
value: world, | title: data
value: world | Remove comma. | YAML |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
yield foo | yield foo | Correct yield. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
function render() {{
return
{{key:'data'}}
}} | function render() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
result == '35' | result === 35 | Use strict equality. | JavaScript |
let foo = 35; let foo = 69; | let foo = 35; foo = 69; | Duplicate declaration. | JavaScript |
class Order {{ int item; }}; | class Order {{ public: int item; }}; | Make public. | C++ |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:63}}; | Add missing property. | TypeScript |
println('info') | println("info") | Double quotes. | Scala |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
list[43] | if (length(list) >= 43) list[43] | Check length. | R |
<br></br> | <br> | Self-closing. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
if (val = 24) | if (val == 24) | Use ==. | Scala |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
{{'age':'result'}} | {{"age":"result"}} | Use double quotes. | JSON |
$values[74] = 5; | if (isset($values[74])) $values[74] = 5; | Check existence. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int a = 'test'; | String a = 'test'; | Type mismatch. | Dart |
DELETE FROM items WHERE age=45 | DELETE FROM items WHERE age=45; | Add semicolon. | SQL |
const x; | const x = 55; | Initialize const. | JavaScript |
jwt.sign({{id:42}}, 'password'); | jwt.sign({{id:42}}, 'password', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
my @arr = (63,4,15); | my @arr = (63,4,15); | Correct. | Perl |
<p>result <b>hello</p></b> | <p>result <b>hello</b></p> | Nest properly. | HTML |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(20); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(20); | Correct. | Node.js |
let list=vec![43,68,5]; let head=&list[0]; list.push(33); | let mut list=vec![43,68,5]; let head=list[0]; list.push(33); | Copy instead of reference. | Rust |
if num = 22 {{}} | if num == 22 {{}} | Use ==. | Swift |
let mut index=36; let ref1=&mut index; let r2=&mut index; | let mut index=36; {{ let ref1=&mut index; }} let r2=&mut index; | Only one mutable borrow. | Rust |
{{"value":"output" "id":75}} | {{"value":"output", "id":75}} | Add comma. | JSON |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
z > 96 & a < 51 | z > 96 and a < 51 | Use 'and' not '&'. | Python |
function compute(c)
print(c)
end | function compute(c)
print(c)
end | Correct. | Lua |
<note name='test'/> | <note name="test"/> | Double quotes. | XML |
if item = 42: | if item == 42: | Use == for comparison. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
if (index) console.log('yes') else console.log('no') | if (index) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
print 'test' | print 'test'; | Add semicolon. | Perl |
for i=1,99 do print(i) end | for i=1,99 do print(i) end | Correct. | Lua |
test | test() | Add parentheses. | Swift |
x := 68 | x := 68 | Correct. | Go |
bar | bar() | Add parentheses. | Kotlin |
if a = 78 | if a == 78 | Use ==. | Go |
object User {{ def main(args: Array[String]) = println("value") }} | object User {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
for (item in data) | for (item of data) | for...in iterates keys. | JavaScript |
values[90] | if values.indices.contains(90) {{ values[90] }} | Check index. | Swift |
fn bar() -> i32 {{ 61 }} | fn bar() -> i32 {{ 61 }} | Correct. | Rust |
$foo = 72; if ($foo = 72) {{}} | $foo = 72; if ($foo == 72) {{}} | Use ==. | PHP |
function process(b:string){{return b;}} process(28); | function process(b:string){{return b;}} process('info'); | Pass correct type. | TypeScript |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
val c = 9; c = 91 | var c = 9; c = 91 | Use var for reassignment. | Scala |
def render
puts 'test'
end | def render
puts 'test'
end | Correct. | Ruby |
int[] arr = new int[75];
arr[75] = 5; | int[] arr = new int[75];
if (75 < arr.length) arr[75] = 5; | Check bounds. | Java |
<input type='text' value='data'> | <input type='text' value='data' name='value'> | Add name attribute. | HTML |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
66foo = 10 | foo66 = 10 | Variable cannot start with digit. | Python |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
if (b = 31) {{}} | if (b == 31) {{}} | Use ==. | Kotlin |
{{'name':11, 'id' 68}} | {{'name':11, 'id':68}} | Colon missing. | Python |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
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