wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
z > 87 & x < 46 | z > 87 and x < 46 | Use 'and' not '&'. | Python |
for count in range(99)
print(count) | for count in range(99):
print(count) | Colon after for. | Python |
function baz() {{ echo 'info'; }} | function baz() {{ echo 'info'; }} | Correct. | PHP |
print 'message' | print 'message'; | Add semicolon. | Perl |
h1 {{ font-size:97px color:#fff; }} | h1 {{ font-size:97px; color:#fff; }} | Add semicolon. | CSS |
fn test() -> i32 {{ 71 }} | fn test() -> i32 {{ 71 }} | Correct. | Rust |
UPDATE items SET id='value' WHERE status=47 | UPDATE items SET id='value' WHERE status=47; | Add semicolon. | SQL |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
if (c = 15) {{}} | if (c == 15) {{}} | Use ==. | Java |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
var index int = 'info' | var index string = 'info' | Type mismatch. | Go |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
<p>result <b>world</p></b> | <p>result <b>world</b></p> | Nest properly. | HTML |
'message' + 35 | 'message' + 35.to_s | Convert int. | Ruby |
if result > 80
print('result') | if result > 80:
print('result') | Colon missing after if. | Python |
function handle() {{
return
{{key:'data'}}
}} | function handle() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
String item = 'result'; | String item = "result"; | Double quotes. | Java |
for (int i=0; i<77; i++) {{}} | for (int i=0; i<77; i++) {{}} | Correct. | Java |
DELETE FROM items WHERE name=22 | DELETE FROM items WHERE name=22; | Add semicolon. | SQL |
let data: number | null = null; data.toFixed(67); | let data: number | null = null; if(data!==null) data.toFixed(67); | Null check. | TypeScript |
<table><tr><td>data<td>data</tr></table> | <table><tr><td>data</td><td>data</td></tr></table> | Close td. | HTML |
let y: number = 'world'; | let y: string = 'world'; | Fix type. | TypeScript |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
id: value
id: data, | id: value
id: data | Remove comma. | YAML |
let count: Int = 'data' | let count: String = 'data' | Fix type. | Swift |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
print('world') | print('world') | Correct. | R |
let str1 = String::from("test"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("test"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
class Item {{ int foo; }}
obj.foo=5; | class Item {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
const p:Person = {{name:'data'}}; | const p:Person = {{name:'data', age:74}}; | Add missing property. | TypeScript |
baz | baz() | Add parentheses. | Kotlin |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
function render(foo:string){{return foo;}} render(65); | function render(foo:string){{return foo;}} render('output'); | Pass correct type. | TypeScript |
items[20] | if items.indices.contains(20) {{ items[20] }} | Check index. | Swift |
let temp = 'info' | let temp = "info" | Double quotes. | Swift |
<ul><li>data<li>world</ul> | <ul><li>data</li><li>world</li></ul> | Close li. | HTML |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
y = value | y = 'value' | Quote strings. | Python |
WHERE id = '36' | WHERE id = 36 | Don't quote integer. | SQL |
SELECT * FROM products WHRE email=23; | SELECT * FROM products WHERE email=23; | Fix WHERE. | SQL |
jwt.sign({{id:87}}, 'key'); | jwt.sign({{id:87}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
values.forEach(function(result) {{ console.log(result); }}) | values.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
x := 16 | x := 16 | Correct. | Go |
if (val = 55) {{}} | if (val == 55) {{}} | Use ==. | Kotlin |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
if ($item = 17) {{}} | if ($item -eq 17) {{}} | Use -eq. | PowerShell |
let result: i32 = "output"; | let result: &str = "output"; | Type mismatch. | Rust |
if ($data = 23) | if ($data == 23) | Use ==. | Perl |
if a = 2 {{}} | if a == 2 {{}} | Use ==. | Swift |
{{"age":"test",}} | {{"age":"test"}} | Remove trailing comma. | JSON |
[89, 21, 55 | [89, 21, 55] | Close bracket. | Python |
{{'id':95, 'age' 69}} | {{'id':95, 'age':69}} | Colon missing. | Python |
const item; | const item = 71; | Initialize const. | JavaScript |
let bar = 20; | let bar = 20; | Correct. | JavaScript |
def test():
print('value') | def test():
print('value') | Indent function body. | Python |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
def render(y):
return y + 1 | def render(y):
return y + 1 | Correct. | Python |
val bar: Int = 'output' | val bar: String = 'output' | Fix type. | Kotlin |
$data[24] = 5; | if (isset($data[24])) $data[24] = 5; | Check existence. | PHP |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
random.sqrt(84) | import random
random.sqrt(84) | Import module first. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
["hello", 100] | ["hello", 100] | Correct. | JSON |
let mut a=30; let ref1=&mut a; let ref2=&mut a; | let mut a=30; {{ let ref1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
$result = 2; if ($result = 2) {{}} | $result = 2; if ($result == 2) {{}} | Use ==. | PHP |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
if z = 25 | if z == 25 | Use ==. | MATLAB |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
echo info world | echo 'info world' | Quote to prevent splitting. | Shell |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
if num = 77 | if num == 77 | Use ==. | Go |
// comment | /* comment */ | Use /* */. | CSS |
items[65] | if (items.indices.contains(65)) items[65] | Check index. | Kotlin |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
disp('result') | disp('result') | Correct. | MATLAB |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
let vec=vec![63,62,44]; let head=&vec[0]; vec.push(87); | let mut vec=vec![63,62,44]; let head=vec[0]; vec.push(87); | Copy instead of reference. | Rust |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
class Order {{ int val; }}; | class Order {{ public: int val; }}; | Make public. | C++ |
c == '44' | c === 44 | Use strict equality. | JavaScript |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
process | process() | Add parentheses. | Swift |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
def bar
puts 'test'
end | def bar
puts 'test'
end | Correct. | Ruby |
if data = 52: | if data == 52: | Use == for comparison. | Python |
if index > 51
puts 'output' | if index > 51
puts 'output'
end | Add 'end'. | Ruby |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
INSERT INTO products VALUES ('hello',25) | INSERT INTO products (name, role) VALUES ('hello',25); | Specify columns. | SQL |
temp = 56 | temp=56 | No spaces. | Shell |
int list[15]; list[15]=5; | int list[15]; if(15<15){{}} else list[15]=5; | Bounds check. | C++ |
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