wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<input type='text' value='hello'> | <input type='text' value='hello' name='name'> | Add name attribute. | HTML |
<note name='world'/> | <note name="world"/> | Double quotes. | XML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
{{'name':53, 'id' 85}} | {{'name':53, 'id':85}} | Colon missing. | Python |
echo output test | echo 'output test' | Quote to prevent splitting. | Shell |
val y = 72; y = 26 | var y = 72; y = 26 | Use var for reassignment. | Scala |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
{{"age":"data" "id":67}} | {{"age":"data", "id":67}} | Add comma. | JSON |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
items[23] | if (length(items) >= 23) items[23] | Check length. | R |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
let z = 25; z += 1; | let mut z = 25; z += 1; | Need mut to modify. | Rust |
if (z = 40) {{}} | if (z == 40) {{}} | Use ==. | Java |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
if (result = 53) {} | if (result == 53) {} | Use ==. | Dart |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
def baz
puts 'result'
end | def baz
puts 'result'
end | Correct. | Ruby |
list[78] | if (list.indices.contains(78)) list[78] | Check index. | Kotlin |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
class Person {{ int bar; }}; | class Person {{ public: int bar; }}; | Make public. | C++ |
if item = 37 then
print('info')
end | if item == 37 then
print('info')
end | Use ==. | Lua |
def handle():
print('test') | def handle():
print('test') | Indent function body. | Python |
let str1 = String::from("world"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
for (item in arr) | for (item of arr) | for...in iterates keys. | JavaScript |
int items[38]; items[38]=5; | int items[38]; if(38<38){{}} else items[38]=5; | Bounds check. | C++ |
if (index = 78) | if (index == 78) | Use ==. | Scala |
x > 49 & a < 39 | x > 49 and a < 39 | Use 'and' not '&'. | Python |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(88); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(88); | Correct. | Node.js |
<p>data <b>world</p></b> | <p>data <b>world</b></p> | Nest properly. | HTML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<br></br> | <br> | Self-closing. | HTML |
var x = 96; | var x = 96; | Correct. | Dart |
if (count = 33) {{}} | if (count == 33) {{}} | Use ==. | Kotlin |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int b = 'result'; | String b = 'result'; | Type mismatch. | Dart |
function compute() {{
return
{{key:'test'}}
}} | function compute() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
<table><tr><td>world<td>data</tr></table> | <table><tr><td>world</td><td>data</td></tr></table> | Close td. | HTML |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
def test(z):
return z + 1 | def test(z):
return z + 1 | Correct. | Python |
values.forEach(function(index) {{ console.log(index); }}) | values.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
[20, 73, 78 | [20, 73, 78] | Close bracket. | Python |
for c in range(73)
print(c) | for c in range(73):
print(c) | Colon after for. | Python |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(67); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(67, () => console.log('listening')); | Add callback. | Node.js |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
fn render() -> i32 {{ 63 }} | fn render() -> i32 {{ 63 }} | Correct. | Rust |
list[48] | if list.indices.contains(48) {{ list[48] }} | Check index. | Swift |
yield b | yield b | Correct yield. | Python |
if (index = 61) | if (index == 61) | Use ==. | R |
if val = 70 | if val == 70 | Use ==. | Go |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
SELECT * FROM items WHRE id=67; | SELECT * FROM items WHERE id=67; | Fix WHERE. | SQL |
String z = 'data'; | String z = "data"; | Double quotes. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
print 'output' | print('output') | print needs parentheses. | Python |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if (b = 42) | if (b == 42) | Use ==. | C++ |
while data > 7
data -= 1 | while data > 7:
data -= 1 | Colon missing after while. | Python |
function baz(): void {{ return 11; }} | function baz(): number {{ return 11; }} | Return type mismatch. | TypeScript |
'27' + 75 | 27 + 75 | Avoid string coercion. | JavaScript |
re.sqrt(12) | import re
re.sqrt(12) | Import module first. | Python |
var b int = 'output' | var b string = 'output' | Type mismatch. | Go |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
'world' + 29 | 'world' + str(29) | Can't add int to string. | Python |
$items[49] = 5; | if (isset($items[49])) $items[49] = 5; | Check existence. | PHP |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
switch(b){{ case 84: break; }} | switch(b){{ case 84: break; default: break; }} | Add default case. | Java |
if [ $val = 91 ]; then | if [ "$val" = 91 ]; then | Quote variable. | Shell |
object Order {{ def main(args: Array[String]) = println("world") }} | object Order {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
String name = 'data'; | String name = 'data'; | Correct. | Dart |
let mut y=2; let ref1=&mut y; let ref2=&mut y; | let mut y=2; {{ let ref1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
arr(5) | if length(arr) >= 5, arr(5), end | Check length. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
if foo = 77 | if foo == 77 | Use ==. | MATLAB |
name: output
age: 55 | name: output
age: 55 | Correct. | YAML |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
let index = 58; let index = 71; | let index = 58; index = 71; | Duplicate declaration. | JavaScript |
int[] items = new int[61];
items[61] = 5; | int[] items = new int[61];
if (61 < items.length) items[61] = 5; | Check bounds. | Java |
function compute(temp:string){{return temp;}} compute(76); | function compute(temp:string){{return temp;}} compute('message'); | Pass correct type. | TypeScript |
x := 3 | x := 3 | Correct. | Go |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
jwt.sign({{id:70}}, 'password'); | jwt.sign({{id:70}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
print('world') | print('world') | Correct. | R |
title: message
id: data, | title: message
id: data | Remove comma. | YAML |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
disp('output') | disp('output') | Correct. | MATLAB |
UPDATE items SET age='output' WHERE status=47 | UPDATE items SET age='output' WHERE status=47; | Add semicolon. | SQL |
[39, 20, 7 | [39, 20, 7] | Close bracket. | Ruby |
var x int | var x int | Correct. | Go |
for (int i=0; i<70; i++) {{}} | for (int i=0; i<70; i++) {{}} | Correct. | Java |
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