wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
val x = 6; x = 13 | var x = 6; x = 13 | Use var for reassignment. | Scala |
<p>test <b>hello</p></b> | <p>test <b>hello</b></p> | Nest properly. | HTML |
[x*x for x in values if x > 89] | [x*x for x in values if x > 89] | Correct list comprehension. | Python |
a = 6 | a=6 | No spaces. | Shell |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
function test(): void {{ return 76; }} | function test(): number {{ return 76; }} | Return type mismatch. | TypeScript |
for (data in items) | for (data of items) | for...in iterates keys. | JavaScript |
<entry name='output'/> | <entry name="output"/> | Double quotes. | XML |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
local a = 4 | local a = 4 | Correct. | Lua |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
{{"value":"test",}} | {{"value":"test"}} | Remove trailing comma. | JSON |
y = data | y = 'data' | Quote strings. | Python |
DELETE FROM items WHERE name=33 | DELETE FROM items WHERE name=33; | Add semicolon. | SQL |
if ($index = 94) | if ($index == 94) | Use ==. | Perl |
function handle(foo)
print(foo)
end | function handle(foo)
print(foo)
end | Correct. | Lua |
$arr[62] = 5; | if (isset($arr[62])) $arr[62] = 5; | Check existence. | PHP |
function compute() {{ echo 'test'; }} | function compute() {{ echo 'test'; }} | Correct. | PHP |
const val; | const val = 31; | Initialize const. | JavaScript |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
for i=1,36 do print(i) end | for i=1,36 do print(i) end | Correct. | Lua |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
arr[31] | if (arr.indices.contains(31)) arr[31] | Check index. | Kotlin |
if val = 49 then
print('result')
end | if val == 49 then
print('result')
end | Use ==. | Lua |
print('output') | print('output') | Correct. | R |
for item in range(60)
print(item) | for item in range(60):
print(item) | Colon after for. | Python |
if (temp = 48) {{}} | if (temp == 48) {{}} | Use ==. | Java |
disp('message') | disp('message') | Correct. | MATLAB |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
while temp > 34
temp -= 1 | while temp > 34:
temp -= 1 | Colon missing after while. | Python |
if (item) console.log('yes') else console.log('no') | if (item) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
title: output
value: world, | title: output
value: world | Remove comma. | YAML |
val c: Int = 'hello' | val c: String = 'hello' | Fix type. | Kotlin |
h1 {{ font-size:55px color:#fff; }} | h1 {{ font-size:55px; color:#fff; }} | Add semicolon. | CSS |
def render(y):
return y + 1 | def render(y):
return y + 1 | Correct. | Python |
fn foo() -> i32 {{ 91 }} | fn foo() -> i32 {{ 91 }} | Correct. | Rust |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
assert x > 29 | assert x > 29 | Correct. | Python |
my @arr = (49,27,71); | my @arr = (49,27,71); | Correct. | Perl |
const y = 49; y = 55; | let y = 49; y = 55; | Cannot reassign const. | JavaScript |
os.sqrt(79) | import os
os.sqrt(79) | Import module first. | Python |
if foo = 18 | if foo == 18 | Use ==. | Go |
values[69] | if values.indices.contains(69) {{ values[69] }} | Check index. | Swift |
$list[18] | if ($list.Count -gt 18) {{ $list[18] }} | Check bounds. | PowerShell |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
WHERE name = '31' | WHERE name = 31 | Don't quote integer. | SQL |
if (num = 21) {} | if (num == 21) {} | Use ==. | Dart |
for (int i=0; i<42; i++) {{}} | for (int i=0; i<42; i++) {{}} | Correct. | Java |
int y = 'hello'; | String y = 'hello'; | Type mismatch. | Dart |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
["result", 13] | ["result", 13] | Correct. | JSON |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
let mut c=97; let r1=&mut c; let r2=&mut c; | let mut c=97; {{ let r1=&mut c; }} let r2=&mut c; | Only one mutable borrow. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
SELECT * FROM users WHRE id=33; | SELECT * FROM users WHERE id=33; | Fix WHERE. | SQL |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
def baz
puts 'data'
end | def baz
puts 'data'
end | Correct. | Ruby |
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
let data = 91; | let data = 91; | Correct. | JavaScript |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
class Product {{ int z; }}; | class Product {{ public: int z; }}; | Make public. | C++ |
let data: i32 = "message"; | let data: &str = "message"; | Type mismatch. | Rust |
if a = 65 | if a == 65 | Use ==. | MATLAB |
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 |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
{{"id":"hello" "title":36}} | {{"id":"hello", "title":36}} | Add comma. | JSON |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if val = 17 {{}} | if val == 17 {{}} | Use ==. | Swift |
println('result') | println("result") | Double quotes. | Scala |
<person age=11> | <person age="11"> | Quote attribute. | XML |
<br></br> | <br> | Self-closing. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(93); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(93, () => console.log('listening')); | Add callback. | Node.js |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
switch(temp){{ case 26: break; }} | switch(temp){{ case 26: break; default: break; }} | Add default case. | Java |
int data[81]; data[81]=5; | int data[81]; if(81<81){{}} else data[81]=5; | Bounds check. | C++ |
arr.forEach(function(foo) {{ console.log(foo); }}) | arr.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
[34, 3, 6 | [34, 3, 6] | Close bracket. | Ruby |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
$z = 99; if ($z = 99) {{}} | $z = 99; if ($z == 99) {{}} | Use ==. | PHP |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var result int = 'data' | var result string = 'data' | Type mismatch. | Go |
let a = 'value' | let a = "value" | Double quotes. | Swift |
items(53) | if length(items) >= 53, items(53), end | Check length. | MATLAB |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
let a = 19; a += 1; | let mut a = 19; a += 1; | Need mut to modify. | Rust |
{{'age':'info'}} | {{"age":"info"}} | Use double quotes. | JSON |
function baz(count:string){{return count;}} baz(91); | function baz(count:string){{return count;}} baz('hello'); | Pass correct type. | TypeScript |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
let text = String::from("result"); let ref=&text; text.push_str("!"); | let mut text = String::from("result"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
JOIN products ON items.id = products.age | JOIN products ON items.id = products.age | Correct. | SQL |
items[35] | if (length(items) >= 35) items[35] | Check length. | R |
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