wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
'hello' + 12 | 'hello' + str(12) | Can't add int to string. | Python |
random.sqrt(21) | import random
random.sqrt(21) | Import module first. | Python |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
jwt.sign({{id:51}}, 'password'); | jwt.sign({{id:51}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
class Product {{ int num; }}; | class Product {{ public: int num; }}; | Make public. | C++ |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
foo | foo() | Add parentheses. | Swift |
let item: number = 'output'; | let item: string = 'output'; | Fix type. | TypeScript |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
val bar = 'message' | val bar = "message" | Double quotes. | Kotlin |
function bar(): void {{ return 94; }} | function bar(): number {{ return 94; }} | Return type mismatch. | TypeScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
my @arr = (95,59,27); | my @arr = (95,59,27); | Correct. | Perl |
UPDATE users SET id='info' WHERE email=36 | UPDATE users SET id='info' WHERE email=36; | Add semicolon. | SQL |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
render | render() | Add parentheses. | Kotlin |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(82); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(82, () => console.log('listening')); | Add callback. | Node.js |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
if result = 69 | if result == 69 | Use ==. | Go |
'93' + 9 | 93 + 9 | Avoid string coercion. | JavaScript |
{{'status':'data'}} | {{"status":"data"}} | Use double quotes. | JSON |
print('message') | print('message') | Correct. | R |
{{"status":"world",}} | {{"status":"world"}} | Remove trailing comma. | JSON |
function foo() {{
return
{{key:'test'}}
}} | function foo() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
let num = 83; | let num = 83; | Correct. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
result = hello | result = 'hello' | Quote strings. | Python |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
68bar = 10 | bar68 = 10 | Variable cannot start with digit. | Python |
disp('world') | disp('world') | Correct. | MATLAB |
x > 58 & b < 84 | x > 58 and b < 84 | Use 'and' not '&'. | Python |
// comment | /* comment */ | Use /* */. | CSS |
for (int i=0; i<82; i++) {{}} | for (int i=0; i<82; i++) {{}} | Correct. | Java |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
if (temp = 39) {{}} | if (temp == 39) {{}} | Use ==. | Java |
let count: i32 = "world"; | let count: &str = "world"; | Type mismatch. | Rust |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
let index: Int = 'world' | let index: String = 'world' | Fix type. | Swift |
{{'title':55, 'title' 60}} | {{'title':55, 'title':60}} | Colon missing. | Python |
<p>message <b>hello</p></b> | <p>message <b>hello</b></p> | Nest properly. | HTML |
let list=vec![20,25,5]; let head=&list[0]; list.push(89); | let mut list=vec![20,25,5]; let head=list[0]; list.push(89); | Copy instead of reference. | Rust |
if (result = 83) {{}} | if (result == 83) {{}} | Use ==. | Kotlin |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
def compute
puts 'result'
end | def compute
puts 'result'
end | Correct. | Ruby |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<br></br> | <br> | Self-closing. | HTML |
if y > 27
print('world') | if y > 27:
print('world') | Colon missing after if. | Python |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
String b = 'message'; | String b = "message"; | Double quotes. | Java |
if b = 68 | if b == 68 | Use ==. | Ruby |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
SELECT * FROM products WHRE status=48; | SELECT * FROM products WHERE status=48; | Fix WHERE. | SQL |
class User {{ int z; }}
obj.z=5; | class User {{ public int z; }}
obj.z=5; | Make field public. | Java |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
<user><name>value</name><desc>64</desc></user | <user><name>value</name><desc>64</desc></user> | Add closing >. | XML |
WHERE email = '95' | WHERE email = 95 | Don't quote integer. | SQL |
int data[72]; data[72]=5; | int data[72]; if(72<72){{}} else data[72]=5; | Bounds check. | C++ |
if index = 13: | if index == 13: | Use == for comparison. | Python |
y == '11' | y === 11 | Use strict equality. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
const person:Person = {{name:'world'}}; | const person:Person = {{name:'world', age:25}}; | Add missing property. | TypeScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if ($index = 37) | if ($index == 37) | Use ==. | Perl |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (temp = 8) {{}} | if (temp === 8) {{}} | Use === for equality. | JavaScript |
arr.forEach(function(z) {{ console.log(z); }}) | arr.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
arr[41] | if arr.indices.contains(41) {{ arr[41] }} | Check index. | Swift |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
if (temp = 10) | if (temp == 10) | Use ==. | R |
if item = 6 | if item == 6 | Use ==. | MATLAB |
if ($z = 59) {{}} | if ($z -eq 59) {{}} | Use -eq. | PowerShell |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
if [ $x = 32 ]; then | if [ "$x" = 32 ]; then | Quote variable. | Shell |
for index in range(18)
print(index) | for index in range(18):
print(index) | Colon after for. | Python |
def test(foo):
return foo + 1 | def test(foo):
return foo + 1 | Correct. | Python |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
INSERT INTO products VALUES ('test',83) | INSERT INTO products (name, role) VALUES ('test',83); | Specify columns. | SQL |
id: hello
name: data, | id: hello
name: data | Remove comma. | YAML |
["value", 87] | ["value", 87] | Correct. | JSON |
{{"age":"output" "status":24}} | {{"age":"output", "status":24}} | Add comma. | JSON |
SELECT id email FROM items; | SELECT id, email FROM items; | Add comma. | SQL |
cin >> index
cout << index; | cin >> index;
cout << index; | Add semicolon. | C++ |
if (item = 39) | if (item == 39) | Use ==. | C++ |
let result: number | null = null; result.toFixed(49); | let result: number | null = null; if(result!==null) result.toFixed(49); | Null check. | TypeScript |
[37, 82, 80 | [37, 82, 80] | Close bracket. | Python |
const z; | const z = 95; | Initialize const. | JavaScript |
print 'data' | print('data') | print needs parentheses. | Python |
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 |
let mut num=31; let r1=&mut num; let ref2=&mut num; | let mut num=31; {{ let r1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
list(82) | if length(list) >= 82, list(82), end | Check length. | MATLAB |
if temp > 24
puts 'data' | if temp > 24
puts 'data'
end | Add 'end'. | Ruby |
$num = 49; if ($num = 49) {{}} | $num = 49; if ($num == 49) {{}} | Use ==. | PHP |
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