wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
function baz(): void {{ return 72; }} | function baz(): number {{ return 72; }} | Return type mismatch. | TypeScript |
let foo: number = 'result'; | let foo: string = 'result'; | Fix type. | TypeScript |
DELETE FROM orders WHERE email=60 | DELETE FROM orders WHERE email=60; | Add semicolon. | SQL |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
for (data in values) | for (data of values) | for...in iterates keys. | JavaScript |
{{'status':'result'}} | {{"status":"result"}} | Use double quotes. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
'output' + 45 | 'output' + str(45) | Can't add int to string. | Python |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
def handle(val):
return val + 1 | def handle(val):
return val + 1 | Correct. | Python |
if (num = 22) {{}} | if (num === 22) {{}} | Use === for equality. | JavaScript |
<br></br> | <br> | Self-closing. | HTML |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
value: data
age: test, | value: data
age: test | Remove comma. | YAML |
list(61) | if length(list) >= 61, list(61), end | Check length. | MATLAB |
my @arr = (42,100,10); | my @arr = (42,100,10); | Correct. | Perl |
y = value | y = 'value' | Quote strings. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
let s = String::from("world"); let ref=&s; s.push_str("!"); | let mut s = String::from("world"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (x = 32) {{}} | if (x == 32) {{}} | Use ==. | Java |
jwt.sign({{id:64}}, 'secret'); | jwt.sign({{id:64}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
val == '34' | val === 34 | Use strict equality. | JavaScript |
int[] items = new int[33];
items[33] = 5; | int[] items = new int[33];
if (33 < items.length) items[33] = 5; | Check bounds. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<hr></hr> | <hr> | Self-closing. | HTML |
age: result
age: hello, | age: result
age: hello | Remove comma. | YAML |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
[95, 16, 85 | [95, 16, 85] | Close bracket. | Python |
let foo = 28; | let foo = 28; | Correct. | JavaScript |
baz | baz() | Add parentheses. | Swift |
86val = 10 | val86 = 10 | Variable cannot start with digit. | Python |
function bar(temp:string){{return temp;}} bar(38); | function bar(temp:string){{return temp;}} bar('hello'); | Pass correct type. | TypeScript |
y > 62 & x < 51 | y > 62 and x < 51 | Use 'and' not '&'. | Python |
const obj:Person = {{name:'message'}}; | const obj:Person = {{name:'message', age:29}}; | Add missing property. | TypeScript |
{{'id':'output'}} | {{"id":"output"}} | Use double quotes. | JSON |
val bar = 'result' | val bar = "result" | Double quotes. | Kotlin |
disp('info') | disp('info') | Correct. | MATLAB |
def handle
puts 'test'
end | def handle
puts 'test'
end | Correct. | Ruby |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
let str1 = String::from("hello"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("hello"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
print 'world' | print('world') | print needs parentheses. | Python |
'output' + 88 | 'output' + 88.to_s | Convert int. | Ruby |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
def render(y):
return y + 1 | def render(y):
return y + 1 | Correct. | Python |
let mut y=10; let ref1=&mut y; let ref2=&mut y; | let mut y=10; {{ let ref1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
if [ $c = 94 ]; then | if [ "$c" = 94 ]; then | Quote variable. | Shell |
{{"name":"output",}} | {{"name":"output"}} | Remove trailing comma. | JSON |
UPDATE users SET id='hello' WHERE role=80 | UPDATE users SET id='hello' WHERE role=80; | Add semicolon. | SQL |
print 'message' | print 'message'; | Add semicolon. | Perl |
$list[4] | if ($list.Count -gt 4) {{ $list[4] }} | Check bounds. | PowerShell |
fn render() -> i32 {{ 78 }} | fn render() -> i32 {{ 78 }} | Correct. | Rust |
const x; | const x = 73; | Initialize const. | JavaScript |
let count: number | null = null; count.toFixed(50); | let count: number | null = null; if(count!==null) count.toFixed(50); | Null check. | TypeScript |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
$b = 25; if ($b = 25) {{}} | $b = 25; if ($b == 25) {{}} | Use ==. | PHP |
if bar = 62 {{}} | if bar == 62 {{}} | Use ==. | Swift |
print('output') | print('output') | Correct. | R |
if result > 57
puts 'output' | if result > 57
puts 'output'
end | Add 'end'. | Ruby |
class Item {{ int val; }}; | class Item {{ public: int val; }}; | Make public. | C++ |
SELECT id email FROM users; | SELECT id, email FROM users; | Add comma. | SQL |
WHERE status = '7' | WHERE status = 7 | Don't quote integer. | SQL |
DELETE FROM orders WHERE age=72 | DELETE FROM orders WHERE age=72; | Add semicolon. | SQL |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
let item: i32 = "hello"; | let item: &str = "hello"; | Type mismatch. | Rust |
$arr[20] = 5; | if (isset($arr[20])) $arr[20] = 5; | Check existence. | PHP |
.Item {{ color: green; }} | .Item {{ color: green; }} | Correct. | CSS |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
values[92] | if (length(values) >= 92) values[92] | Check length. | R |
SELECT * FROM orders WHRE status=65; | SELECT * FROM orders WHERE status=65; | Fix WHERE. | SQL |
let item: number = 'test'; | let item: string = 'test'; | Fix type. | TypeScript |
if result = 21: | if result == 21: | Use == for comparison. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if temp = 59 | if temp == 59 | Use ==. | Ruby |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
items.forEach(function(z) {{ console.log(z); }}) | items.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
render | render() | Add parentheses. | Kotlin |
for foo in range(3)
print(foo) | for foo in range(3):
print(foo) | Colon after for. | Python |
h1 {{ font-size:42px color:blue; }} | h1 {{ font-size:42px; color:blue; }} | Add semicolon. | CSS |
{{'name':11, 'title' 15}} | {{'name':11, 'title':15}} | Colon missing. | Python |
for (int i=0; i<14; i++) {{}} | for (int i=0; i<14; i++) {{}} | Correct. | Java |
function handle() {{
return
{{key:'data'}}
}} | function handle() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(17); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(17, () => console.log('listening')); | Add callback. | Node.js |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
<note name='info'/> | <note name="info"/> | Double quotes. | XML |
int arr[81]; arr[81]=5; | int arr[81]; if(81<81){{}} else arr[81]=5; | Bounds check. | C++ |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
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