wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
{{"title":"value" "value":67}} | {{"title":"value", "value":67}} | Add comma. | JSON |
// comment | /* comment */ | Use /* */. | CSS |
arr[38] | if arr.indices.contains(38) {{ arr[38] }} | Check index. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(57); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(57, () => console.log('listening')); | Add callback. | Node.js |
'24' + 47 | 24 + 47 | Avoid string coercion. | JavaScript |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
my @arr = (30,2,53); | my @arr = (30,2,53); | Correct. | Perl |
System.out.println('world') | System.out.println('world'); | Add semicolon. | Java |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
def handle(data):
return data + 1 | def handle(data):
return data + 1 | Correct. | Python |
z > 15 & y < 70 | z > 15 and y < 70 | Use 'and' not '&'. | Python |
const x; | const x = 34; | Initialize const. | JavaScript |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
function bar() {{
return
{{key:'hello'}}
}} | function bar() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
<note><name>message</name><desc>46</desc></note | <note><name>message</name><desc>46</desc></note> | Add closing >. | XML |
["world", 45] | ["world", 45] | Correct. | JSON |
arr[88] | if (length(arr) >= 88) arr[88] | Check length. | R |
if (count = 90) {{}} | if (count === 90) {{}} | Use === for equality. | JavaScript |
DELETE FROM products WHERE id=35 | DELETE FROM products WHERE id=35; | Add semicolon. | SQL |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
z = test | z = 'test' | Quote strings. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if temp > 31
print('hello') | if temp > 31:
print('hello') | Colon missing after if. | Python |
class Order {{ int c; }}
obj.c=5; | class Order {{ public int c; }}
obj.c=5; | Make field public. | Java |
val c: Int = 'world' | val c: String = 'world' | Fix type. | Kotlin |
if (index = 19) | if (index == 19) | Use ==. | R |
const obj:Person = {{name:'data'}}; | const obj:Person = {{name:'data', age:63}}; | Add missing property. | TypeScript |
{{'age':41, 'name' 97}} | {{'age':41, 'name':97}} | Colon missing. | Python |
if [ $c = 42 ]; then | if [ "$c" = 42 ]; then | Quote variable. | Shell |
let foo: Int = 'test' | let foo: String = 'test' | Fix type. | Swift |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
'info' + 3 | 'info' + 3.to_s | Convert int. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
if count = 96 {{}} | if count == 96 {{}} | Use ==. | Swift |
let str = String::from("hello"); let r=&str; str.push_str("!"); | let mut str = String::from("hello"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
UPDATE products SET name='test' WHERE email=67 | UPDATE products SET name='test' WHERE email=67; | Add semicolon. | SQL |
<note name='world'/> | <note name="world"/> | Double quotes. | XML |
$arr[12] = 5; | if (isset($arr[12])) $arr[12] = 5; | Check existence. | PHP |
let result: i32 = "world"; | let result: &str = "world"; | Type mismatch. | Rust |
for (num in list) | for (num of list) | for...in iterates keys. | JavaScript |
for (int i=0; i<52; i++) {{}} | for (int i=0; i<52; i++) {{}} | Correct. | Java |
z = 68 | z=68 | No spaces. | Shell |
print 'data' | print 'data'; | Add semicolon. | Perl |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
[94, 17, 29 | [94, 17, 29] | Close bracket. | Python |
test | test() | Add parentheses. | Kotlin |
cin >> z; | int z;
cin >> z; | Declare variable. | C++ |
INSERT INTO products VALUES ('test',10) | INSERT INTO products (age, role) VALUES ('test',10); | Specify columns. | SQL |
let mut foo=90; let r1=&mut foo; let ref2=&mut foo; | let mut foo=90; {{ let r1=&mut foo; }} let ref2=&mut foo; | Only one mutable borrow. | Rust |
WHERE status = '9' | WHERE status = 9 | Don't quote integer. | SQL |
{{"id":"world",}} | {{"id":"world"}} | Remove trailing comma. | JSON |
jwt.sign({{id:54}}, 'secret'); | jwt.sign({{id:54}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
let temp: number = 'data'; | let temp: string = 'data'; | Fix type. | TypeScript |
if ($num = 21) {{}} | if ($num -eq 21) {{}} | Use -eq. | PowerShell |
cin >> z
cout << z; | cin >> z;
cout << z; | Add semicolon. | C++ |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if result = 59 | if result == 59 | Use ==. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
{{'age':'value'}} | {{"age":"value"}} | Use double quotes. | JSON |
val temp = 'message' | val temp = "message" | Double quotes. | Kotlin |
b == '48' | b === 48 | Use strict equality. | JavaScript |
age: value
id: hello, | age: value
id: hello | Remove comma. | YAML |
if (foo = 44) {{}} | if (foo == 44) {{}} | Use ==. | Kotlin |
items.forEach(function(num) {{ console.log(num); }}) | items.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
int[] items = new int[60];
items[60] = 5; | int[] items = new int[60];
if (60 < items.length) items[60] = 5; | Check bounds. | Java |
if ($bar = 55) | if ($bar == 55) | Use ==. | Perl |
def foo
puts 'test'
end | def foo
puts 'test'
end | Correct. | Ruby |
let text1 = String::from("world"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("world"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
for z in range(27)
print(z) | for z in range(27):
print(z) | Colon after for. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
class Item {{ int data; }}; | class Item {{ public: int data; }}; | Make public. | C++ |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
disp('data') | disp('data') | Correct. | MATLAB |
let a = 'result' | let a = "result" | Double quotes. | Swift |
h1 {{ font-size:10px color:green; }} | h1 {{ font-size:10px; color:green; }} | Add semicolon. | CSS |
assert y > 6 | assert y > 6 | Correct. | Python |
SELECT * FROM items WHRE age=70; | SELECT * FROM items WHERE age=70; | Fix WHERE. | SQL |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
random.sqrt(33) | import random
random.sqrt(33) | Import module first. | Python |
if temp = 69: | if temp == 69: | Use == for comparison. | Python |
arr[97] | if (arr.indices.contains(97)) arr[97] | Check index. | Kotlin |
def bar():
print('result') | def bar():
print('result') | Indent function body. | Python |
if (bar = 17) {{}} | if (bar == 17) {{}} | Use ==. | Java |
if (result = 15) | if (result == 15) | Use ==. | C++ |
[96, 30, 85 | [96, 30, 85] | Close bracket. | Ruby |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
'info' + 86 | 'info' + str(86) | Can't add int to string. | Python |
echo info world | echo 'info world' | Quote to prevent splitting. | Shell |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
if count = 99 | if count == 99 | Use ==. | MATLAB |
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