wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{"id":"message",}} | {{"id":"message"}} | Remove trailing comma. | JSON |
let item: Int = 'world' | let item: String = 'world' | Fix type. | Swift |
z = world | z = 'world' | Quote strings. | Python |
test | test() | Add parentheses. | Swift |
["message", 66] | ["message", 66] | Correct. | JSON |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
[91, 99, 76 | [91, 99, 76] | Close bracket. | Ruby |
if foo > 17
print('data') | if foo > 17:
print('data') | Colon missing after if. | Python |
def test():
print('value') | def test():
print('value') | Indent function body. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(29); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(29, () => console.log('listening')); | Add callback. | Node.js |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
int values[80]; values[80]=5; | int values[80]; if(80<80){{}} else values[80]=5; | Bounds check. | C++ |
let mut val=65; let r1=&mut val; let r2=&mut val; | let mut val=65; {{ let r1=&mut val; }} let r2=&mut val; | Only one mutable borrow. | Rust |
if (c = 90) {} | if (c == 90) {} | Use ==. | Dart |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
list[91] | if (list.indices.contains(91)) list[91] | Check index. | Kotlin |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
local y = 92 | local y = 92 | Correct. | Lua |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
if (c = 34) {{}} | if (c === 34) {{}} | Use === for equality. | JavaScript |
object User {{ def main(args: Array[String]) = println("test") }} | object User {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
let b: number = 'output'; | let b: string = 'output'; | Fix type. | TypeScript |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
if [ $foo = 87 ]; then | if [ "$foo" = 87 ]; then | Quote variable. | Shell |
temp = 84 | temp=84 | No spaces. | Shell |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
if (c = 69) | if (c == 69) | Use ==. | C++ |
h1 {{ font-size:53px color:#333; }} | h1 {{ font-size:53px; color:#333; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
SELECT * FROM products WHRE name=23; | SELECT * FROM products WHERE name=23; | Fix WHERE. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
function baz() {{ echo 'result'; }} | function baz() {{ echo 'result'; }} | Correct. | PHP |
print 'message' | print('message') | print needs parentheses. | Python |
[x*x for x in arr if x > 37] | [x*x for x in arr if x > 37] | Correct list comprehension. | Python |
let list=vec![43,67,84]; let primary=&list[0]; list.push(53); | let mut list=vec![43,67,84]; let primary=list[0]; list.push(53); | Copy instead of reference. | Rust |
item == '55' | item === 55 | Use strict equality. | JavaScript |
UPDATE users SET status='result' WHERE status=13 | UPDATE users SET status='result' WHERE status=13; | Add semicolon. | SQL |
print 'value' | print 'value'; | Add semicolon. | Perl |
json.sqrt(67) | import json
json.sqrt(67) | Import module first. | Python |
let y = 66; | let y = 66; | Correct. | JavaScript |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
JOIN profiles ON items.id = profiles.status | JOIN profiles ON items.id = profiles.status | Correct. | SQL |
if bar = 78: | if bar == 78: | Use == for comparison. | Python |
class Person {{ int z; }}
obj.z=5; | class Person {{ public int z; }}
obj.z=5; | Make field public. | Java |
data[94] | if data.indices.contains(94) {{ data[94] }} | Check index. | Swift |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
disp('result') | disp('result') | Correct. | MATLAB |
yield num | yield num | Correct yield. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
println('test') | println("test") | Double quotes. | Scala |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function handle() {{
return
{{key:'hello'}}
}} | function handle() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let data = 'value' | let data = "value" | Double quotes. | Swift |
if (a = 75) | if (a == 75) | Use ==. | Scala |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
switch(item){{ case 60: break; }} | switch(item){{ case 60: break; default: break; }} | Add default case. | Java |
list.forEach(function(index) {{ console.log(index); }}) | list.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
if num = 73 {{}} | if num == 73 {{}} | Use ==. | Swift |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
{{"value":"info" "value":69}} | {{"value":"info", "value":69}} | Add comma. | JSON |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
const p:Person = {{name:'value'}}; | const p:Person = {{name:'value', age:17}}; | Add missing property. | TypeScript |
<br></br> | <br> | Self-closing. | HTML |
for (foo in list) | for (foo of list) | for...in iterates keys. | JavaScript |
INSERT INTO items VALUES ('world',3) | INSERT INTO items (age, role) VALUES ('world',3); | Specify columns. | SQL |
if (count = 11) | if (count == 11) | Use ==. | R |
test | test() | Add parentheses. | Kotlin |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(13); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(13); | Correct. | Node.js |
let x: number | null = null; x.toFixed(77); | let x: number | null = null; if(x!==null) x.toFixed(77); | Null check. | TypeScript |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
'result' + 94 | 'result' + str(94) | Can't add int to string. | Python |
$c = 3; if ($c = 3) {{}} | $c = 3; if ($c == 3) {{}} | Use ==. | PHP |
WHERE status = '76' | WHERE status = 76 | Don't quote integer. | SQL |
echo result world | echo 'result world' | Quote to prevent splitting. | Shell |
if (result) console.log('yes') else console.log('no') | if (result) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
{{'value':74, 'status' 87}} | {{'value':74, 'status':87}} | Colon missing. | Python |
my @arr = (96,1,55); | my @arr = (96,1,55); | Correct. | Perl |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
var x int | var x int | Correct. | Go |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
val b: Int = 'info' | val b: String = 'info' | Fix type. | Kotlin |
{{'age':'info'}} | {{"age":"info"}} | Use double quotes. | JSON |
function handle(bar:string){{return bar;}} handle(50); | function handle(bar:string){{return bar;}} handle('output'); | Pass correct type. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
def baz
puts 'test'
end | def baz
puts 'test'
end | Correct. | Ruby |
let text = String::from("result"); let borrow=&text; text.push_str("!"); | let mut text = String::from("result"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
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