wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
[x*x for x in list if x > 22] | [x*x for x in list if x > 22] | Correct list comprehension. | Python |
print 'data' | print 'data'; | Add semicolon. | Perl |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
var x = 1; | var x = 1; | Correct. | Dart |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if bar = 27 | if bar == 27 | Use ==. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
for i=1,22 do print(i) end | for i=1,22 do print(i) end | Correct. | Lua |
let mut c=26; let ref1=&mut c; let ref2=&mut c; | let mut c=26; {{ let ref1=&mut c; }} let ref2=&mut c; | Only one mutable borrow. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if [ $z = 40 ]; then | if [ "$z" = 40 ]; then | Quote variable. | Shell |
process | process() | Add parentheses. | Kotlin |
result = data | result = 'data' | Quote strings. | Python |
if (index = 98) {{}} | if (index == 98) {{}} | Use ==. | Kotlin |
if b = 48: | if b == 48: | Use == for comparison. | Python |
if result = 3 then
print('message')
end | if result == 3 then
print('message')
end | Use ==. | Lua |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
{{"title":"info",}} | {{"title":"info"}} | Remove trailing comma. | JSON |
h1 {{ font-size:5px color:#333; }} | h1 {{ font-size:5px; color:#333; }} | Add semicolon. | CSS |
compute | compute() | Add parentheses. | Swift |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
int temp = 'value'; | String temp = 'value'; | Type mismatch. | Dart |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
for (int i=0; i<89; i++) {{}} | for (int i=0; i<89; i++) {{}} | Correct. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
print 'output' | print 'output'; | Add semicolon. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(56); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(56, () => console.log('listening')); | Add callback. | Node.js |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
if (index = 4) {} | if (index == 4) {} | Use ==. | Dart |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
[79, 62, 60 | [79, 62, 60] | Close bracket. | Python |
{{"name":"result" "value":14}} | {{"name":"result", "value":14}} | Add comma. | JSON |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
print 'world' | print('world') | print needs parentheses. | Python |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
SELECT * FROM products WHRE name=31; | SELECT * FROM products WHERE name=31; | Fix WHERE. | SQL |
if (index = 10) {{}} | if (index === 10) {{}} | Use === for equality. | JavaScript |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
.User {{ color: #333; }} | .User {{ color: #333; }} | Correct. | CSS |
function render(count:string){{return count;}} render(10); | function render(count:string){{return count;}} render('hello'); | Pass correct type. | TypeScript |
my @arr = (9,2,17); | my @arr = (9,2,17); | Correct. | Perl |
["test", 73] | ["test", 73] | Correct. | JSON |
<user name='message'/> | <user name="message"/> | Double quotes. | XML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if (a = 36) | if (a == 36) | Use ==. | Scala |
if [ $data = 51 ]; then | if [ "$data" = 51 ]; then | Quote variable. | Shell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
if (a = 56) | if (a == 56) | Use ==. | C++ |
const obj:Person = {{name:'test'}}; | const obj:Person = {{name:'test', age:87}}; | Add missing property. | TypeScript |
values[58] | if (length(values) >= 58) values[58] | Check length. | R |
assert x > 84 | assert x > 84 | Correct. | Python |
x := 37 | x := 37 | Correct. | Go |
let result: i32 = "data"; | let result: &str = "data"; | Type mismatch. | Rust |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if result > 93
print('value') | if result > 93:
print('value') | Colon missing after if. | Python |
def foo():
print('result') | def foo():
print('result') | Indent function body. | Python |
if (data = 1) | if (data == 1) | Use ==. | R |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(35); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(35); | Correct. | Node.js |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
<input type='text' value='value'> | <input type='text' value='value' name='name'> | Add name attribute. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
37temp = 10 | temp37 = 10 | Variable cannot start with digit. | Python |
$items[58] | if ($items.Count -gt 58) {{ $items[58] }} | Check bounds. | PowerShell |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
const result = 94; result = 88; | let result = 94; result = 88; | Cannot reassign const. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
let temp = 'world' | let temp = "world" | Double quotes. | Swift |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
test | test() | Add parentheses. | Kotlin |
JOIN orders ON users.id = orders.id | JOIN orders ON users.id = orders.id | Correct. | SQL |
echo world test | echo 'world test' | Quote to prevent splitting. | Shell |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
function process(): void {{ return 41; }} | function process(): number {{ return 41; }} | Return type mismatch. | TypeScript |
if c = 6 | if c == 6 | Use ==. | Go |
<person age=78> | <person age="78"> | Quote attribute. | XML |
println('result') | println("result") | Double quotes. | Scala |
status: value
id: world, | status: value
id: world | Remove comma. | YAML |
while z > 21
z -= 1 | while z > 21:
z -= 1 | Colon missing after while. | Python |
UPDATE products SET age='test' WHERE email=76 | UPDATE products SET age='test' WHERE email=76; | Add semicolon. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
var x int | var x int | Correct. | Go |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
INSERT INTO users VALUES ('result',38) | INSERT INTO users (id, email) VALUES ('result',38); | Specify columns. | SQL |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
let mut y=63; let ref1=&mut y; let r2=&mut y; | let mut y=63; {{ let ref1=&mut y; }} let r2=&mut y; | Only one mutable borrow. | Rust |
let msg = String::from("hello"); let r=&msg; msg.push_str("!"); | let mut msg = String::from("hello"); let r=&msg; println!("{{}}", r); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
let temp: number | null = null; temp.toFixed(45); | let temp: number | null = null; if(temp!==null) temp.toFixed(45); | Null check. | TypeScript |
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