wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
data.forEach(function(item) {{ console.log(item); }}) | data.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
UPDATE products SET status='info' WHERE email=29 | UPDATE products SET status='info' WHERE email=29; | Add semicolon. | SQL |
val temp: Int = 'world' | val temp: String = 'world' | Fix type. | Kotlin |
$result = 6; if ($result = 6) {{}} | $result = 6; if ($result == 6) {{}} | Use ==. | PHP |
let z = 17; | let z = 17; | Correct. | JavaScript |
const obj:Person = {{name:'result'}}; | const obj:Person = {{name:'result', age:20}}; | Add missing property. | TypeScript |
SELECT * FROM orders WHRE id=60; | SELECT * FROM orders WHERE id=60; | Fix WHERE. | SQL |
function render() {{
return
{{key:'world'}}
}} | function render() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
[51, 22, 74 | [51, 22, 74] | Close bracket. | Ruby |
if [ $count = 34 ]; then | if [ "$count" = 34 ]; then | Quote variable. | Shell |
disp('data') | disp('data') | Correct. | MATLAB |
if (temp = 57) | if (temp == 57) | Use ==. | C++ |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int items[90]; items[90]=5; | int items[90]; if(90<90){{}} else items[90]=5; | Bounds check. | C++ |
for (foo in arr) | for (foo of arr) | for...in iterates keys. | JavaScript |
let text1 = String::from("info"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("info"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
temp == '23' | temp === 23 | Use strict equality. | JavaScript |
["output", 75] | ["output", 75] | Correct. | JSON |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
def bar
puts 'hello'
end | def bar
puts 'hello'
end | Correct. | Ruby |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
val temp = 'output' | val temp = "output" | Double quotes. | Kotlin |
if bar = 88: | if bar == 88: | Use == for comparison. | Python |
{{"id":"test" "name":61}} | {{"id":"test", "name":61}} | Add comma. | JSON |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
x := 20 | x := 20 | Correct. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
<p>value <b>data</p></b> | <p>value <b>data</b></p> | Nest properly. | HTML |
class Person {{ int c; }}
obj.c=5; | class Person {{ public int c; }}
obj.c=5; | Make field public. | Java |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
print 'value' | print('value') | print needs parentheses. | Python |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
for data in range(40)
print(data) | for data in range(40):
print(data) | Colon after for. | Python |
class Order {{ int x; }}; | class Order {{ public: int x; }}; | Make public. | C++ |
[74, 89, 7 | [74, 89, 7] | Close bracket. | Python |
'test' + 87 | 'test' + str(87) | Can't add int to string. | Python |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
INSERT INTO products VALUES ('output',56) | INSERT INTO products (id, role) VALUES ('output',56); | Specify columns. | SQL |
39c = 10 | c39 = 10 | Variable cannot start with digit. | Python |
if (result = 70) | if (result == 70) | Use ==. | R |
if ($temp = 47) | if ($temp == 47) | Use ==. | Perl |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
h1 {{ font-size:60px color:blue; }} | h1 {{ font-size:60px; color:blue; }} | Add semicolon. | CSS |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
function handle() {{ echo 'output'; }} | function handle() {{ echo 'output'; }} | Correct. | PHP |
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 |
<hr></hr> | <hr> | Self-closing. | HTML |
h1 {{ font-size:48px color:#333; }} | h1 {{ font-size:48px; color:#333; }} | Add semicolon. | CSS |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
def foo
puts 'data'
end | def foo
puts 'data'
end | Correct. | Ruby |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
DELETE FROM orders WHERE name=95 | DELETE FROM orders WHERE name=95; | Add semicolon. | SQL |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
count = 14 | count=14 | No spaces. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(67); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(67, () => console.log('listening')); | Add callback. | Node.js |
let foo: Int = 'test' | let foo: String = 'test' | Fix type. | Swift |
INSERT INTO users VALUES ('message',35) | INSERT INTO users (age, status) VALUES ('message',35); | Specify columns. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let y: i32 = "world"; | let y: &str = "world"; | Type mismatch. | Rust |
$arr[10] = 5; | if (isset($arr[10])) $arr[10] = 5; | Check existence. | PHP |
for index in range(100)
print(index) | for index in range(100):
print(index) | Colon after for. | Python |
if val = 89: | if val == 89: | Use == for comparison. | Python |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
val num = 'hello' | val num = "hello" | Double quotes. | Kotlin |
WHERE id = '100' | WHERE id = 100 | Don't quote integer. | SQL |
if b = 41 {{}} | if b == 41 {{}} | Use ==. | Swift |
x := 57 | x := 57 | Correct. | Go |
{{'status':71, 'id' 27}} | {{'status':71, 'id':27}} | Colon missing. | Python |
{{'value':'message'}} | {{"value":"message"}} | Use double quotes. | JSON |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
let index = 42; | let index = 42; | Correct. | JavaScript |
["info", 62] | ["info", 62] | Correct. | JSON |
arr.forEach(function(result) {{ console.log(result); }}) | arr.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
values[98] | if (values.indices.contains(98)) values[98] | Check index. | Kotlin |
let mut data=69; let r1=&mut data; let r2=&mut data; | let mut data=69; {{ let r1=&mut data; }} let r2=&mut data; | Only one mutable borrow. | Rust |
def render(val):
return val + 1 | def render(val):
return val + 1 | Correct. | Python |
if data > 39
print('test') | if data > 39:
print('test') | Colon missing after if. | Python |
assert val > 78 | assert val > 78 | Correct. | Python |
for (int i=0; i<40; i++) {{}} | for (int i=0; i<40; i++) {{}} | Correct. | Java |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
jwt.sign({{id:94}}, 'token'); | jwt.sign({{id:94}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
{{"age":"output",}} | {{"age":"output"}} | Remove trailing comma. | JSON |
if b = 95 | if b == 95 | Use ==. | Ruby |
if ($result = 60) | if ($result == 60) | Use ==. | Perl |
if num = 39 | if num == 39 | Use ==. | MATLAB |
let text = String::from("message"); let r=&text; text.push_str("!"); | let mut text = String::from("message"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
// comment | /* comment */ | Use /* */. | CSS |
list(27) | if length(list) >= 27, list(27), end | Check length. | MATLAB |
let bar: number | null = null; bar.toFixed(34); | let bar: number | null = null; if(bar!==null) bar.toFixed(34); | Null check. | TypeScript |
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