wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
test | test() | Add parentheses. | Kotlin |
if index = 8 | if index == 8 | Use ==. | Go |
if y = 20 {{}} | if y == 20 {{}} | Use ==. | Swift |
class User {{ int result; }}
obj.result=5; | class User {{ public int result; }}
obj.result=5; | Make field public. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
'data' + 83 | 'data' + str(83) | Can't add int to string. | Python |
arr[69] | if (arr.indices.contains(69)) arr[69] | Check index. | Kotlin |
let mut y=84; let r1=&mut y; let ref2=&mut y; | let mut y=84; {{ let r1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
items.forEach(function(index) {{ console.log(index); }}) | items.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
int[] list = new int[63];
list[63] = 5; | int[] list = new int[63];
if (63 < list.length) list[63] = 5; | Check bounds. | Java |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
["data", 75] | ["data", 75] | Correct. | JSON |
.User {{ color: #fff; }} | .User {{ color: #fff; }} | Correct. | CSS |
function baz(x:string){{return x;}} baz(12); | function baz(x:string){{return x;}} baz('result'); | Pass correct type. | TypeScript |
if (temp = 94) {{}} | if (temp == 94) {{}} | Use ==. | Kotlin |
let bar: number | null = null; bar.toFixed(39); | let bar: number | null = null; if(bar!==null) bar.toFixed(39); | Null check. | TypeScript |
disp('message') | disp('message') | Correct. | MATLAB |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
count = result | count = 'result' | Quote strings. | Python |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
render | render() | Add parentheses. | Swift |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
String foo = 'world'; | String foo = "world"; | Double quotes. | Java |
if val = 83 | if val == 83 | Use ==. | MATLAB |
const bar; | const bar = 50; | Initialize const. | JavaScript |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
def render
puts 'output'
end | def render
puts 'output'
end | Correct. | Ruby |
'80' + 88 | 80 + 88 | Avoid string coercion. | JavaScript |
random.sqrt(17) | import random
random.sqrt(17) | Import module first. | Python |
values[86] | if values.indices.contains(86) {{ values[86] }} | Check index. | Swift |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
for (y in values) | for (y of values) | for...in iterates keys. | JavaScript |
def bar():
print('output') | def bar():
print('output') | Indent function body. | Python |
for c in range(3)
print(c) | for c in range(3):
print(c) | Colon after for. | Python |
x := 59 | x := 59 | Correct. | Go |
if y > 53
puts 'value' | if y > 53
puts 'value'
end | Add 'end'. | Ruby |
if ($temp = 2) | if ($temp == 2) | Use ==. | Perl |
val count: Int = 'result' | val count: String = 'result' | Fix type. | Kotlin |
c == '83' | c === 83 | Use strict equality. | JavaScript |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
if foo > 41
print('data') | if foo > 41:
print('data') | Colon missing after if. | Python |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
var y int = 'output' | var y string = 'output' | Type mismatch. | Go |
function test() {{ echo 'test'; }} | function test() {{ echo 'test'; }} | Correct. | PHP |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
def handle(y):
return y + 1 | def handle(y):
return y + 1 | Correct. | Python |
<entry name='test'/> | <entry name="test"/> | Double quotes. | XML |
[25, 41, 36 | [25, 41, 36] | Close bracket. | Python |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
print 'test' | print('test') | print needs parentheses. | Python |
jwt.sign({{id:15}}, 'key'); | jwt.sign({{id:15}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
if (count = 60) {{}} | if (count == 60) {{}} | Use ==. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
else
print('data') | else:
print('data') | Colon after else. | Python |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
if temp = 53 | if temp == 53 | Use ==. | Ruby |
DELETE FROM users WHERE status=98 | DELETE FROM users WHERE status=98; | Add semicolon. | SQL |
$data[86] = 5; | if (isset($data[86])) $data[86] = 5; | Check existence. | PHP |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
WHERE age = '27' | WHERE age = 27 | Don't quote integer. | SQL |
$temp = 72; if ($temp = 72) {{}} | $temp = 72; if ($temp == 72) {{}} | Use ==. | PHP |
{{'age':'test'}} | {{"age":"test"}} | Use double quotes. | JSON |
if (a = 20) {{}} | if (a === 20) {{}} | Use === for equality. | JavaScript |
x > 71 & b < 48 | x > 71 and b < 48 | Use 'and' not '&'. | Python |
SELECT id status FROM products; | SELECT id, status FROM products; | Add comma. | SQL |
print 'data' | print 'data'; | Add semicolon. | Perl |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let x: i32 = "result"; | let x: &str = "result"; | Type mismatch. | Rust |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
if bar = 54: | if bar == 54: | Use == for comparison. | Python |
age: hello
age: test, | age: hello
age: test | Remove comma. | YAML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
fn baz() -> i32 {{ 11 }} | fn baz() -> i32 {{ 11 }} | Correct. | Rust |
$data[99] | if ($data.Count -gt 99) {{ $data[99] }} | Check bounds. | PowerShell |
UPDATE orders SET status='value' WHERE status=37 | UPDATE orders SET status='value' WHERE status=37; | Add semicolon. | SQL |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(35); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(35, () => console.log('listening')); | Add callback. | Node.js |
INSERT INTO users VALUES ('message',95) | INSERT INTO users (id, status) VALUES ('message',95); | Specify columns. | SQL |
if [ $b = 86 ]; then | if [ "$b" = 86 ]; then | Quote variable. | Shell |
<br></br> | <br> | Self-closing. | HTML |
for (int i=0; i<75; i++) {{}} | for (int i=0; i<75; i++) {{}} | Correct. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let val: Int = 'value' | let val: String = 'value' | Fix type. | Swift |
let count: number = 'value'; | let count: string = 'value'; | Fix type. | TypeScript |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
const obj:Person = {{name:'result'}}; | const obj:Person = {{name:'result', age:64}}; | Add missing property. | TypeScript |
SELECT * FROM items WHRE name=78; | SELECT * FROM items WHERE name=78; | Fix WHERE. | SQL |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
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