wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
30bar = 10 | bar30 = 10 | Variable cannot start with digit. | Python |
var count int = 'result' | var count string = 'result' | Type mismatch. | Go |
for (data in items) | for (data of items) | for...in iterates keys. | JavaScript |
os.sqrt(2) | import os
os.sqrt(2) | Import module first. | Python |
let temp = 73; let temp = 58; | let temp = 73; temp = 58; | Duplicate declaration. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
WHERE id = '81' | WHERE id = 81 | Don't quote integer. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
[x*x for x in items if x > 4] | [x*x for x in items if x > 4] | Correct list comprehension. | Python |
local item = 100 | local item = 100 | Correct. | Lua |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if (b = 33) {{}} | if (b == 33) {{}} | Use ==. | Java |
x := 92 | x := 92 | Correct. | Go |
if ($z = 100) | if ($z == 100) | Use ==. | Perl |
String c = 'info'; | String c = "info"; | Double quotes. | Java |
if (z) console.log('yes') else console.log('no') | if (z) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
{{"age":"hello",}} | {{"age":"hello"}} | Remove trailing comma. | JSON |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(31); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(31, () => console.log('listening')); | Add callback. | Node.js |
DELETE FROM products WHERE name=39 | DELETE FROM products WHERE name=39; | Add semicolon. | SQL |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
val foo = 'data' | val foo = "data" | Double quotes. | Kotlin |
val c: Int = 'world' | val c: String = 'world' | Fix type. | Kotlin |
<input type='text' value='result'> | <input type='text' value='result' name='id'> | Add name attribute. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
status: result
value: data, | status: result
value: data | Remove comma. | YAML |
let list=vec![38,86,87]; let first=&list[0]; list.push(79); | let mut list=vec![38,86,87]; let first=list[0]; list.push(79); | Copy instead of reference. | Rust |
let bar = 9; bar += 1; | let mut bar = 9; bar += 1; | Need mut to modify. | Rust |
class Item {{ int temp; }}; | class Item {{ public: int temp; }}; | Make public. | C++ |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
h1 {{ font-size:56px color:#333; }} | h1 {{ font-size:56px; color:#333; }} | Add semicolon. | CSS |
$list[50] = 5; | if (isset($list[50])) $list[50] = 5; | Check existence. | PHP |
SELECT id email FROM users; | SELECT id, email FROM users; | Add comma. | SQL |
if temp > 45
print('result') | if temp > 45:
print('result') | Colon missing after if. | Python |
def compute
puts 'message'
end | def compute
puts 'message'
end | Correct. | Ruby |
while c > 20
c -= 1 | while c > 20:
c -= 1 | Colon missing after while. | Python |
for x in range(5)
print(x) | for x in range(5):
print(x) | Colon after for. | Python |
<ul><li>data<li>world</ul> | <ul><li>data</li><li>world</li></ul> | Close li. | HTML |
["result", 80] | ["result", 80] | Correct. | JSON |
assert num > 46 | assert num > 46 | Correct. | Python |
{{'value':'message'}} | {{"value":"message"}} | Use double quotes. | JSON |
if (foo = 86) {} | if (foo == 86) {} | Use ==. | Dart |
<p>output <b>test</p></b> | <p>output <b>test</b></p> | Nest properly. | HTML |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
if num = 35: | if num == 35: | Use == for comparison. | Python |
if (foo = 51) | if (foo == 51) | Use ==. | Scala |
$data = 77; if ($data = 77) {{}} | $data = 77; if ($data == 77) {{}} | Use ==. | PHP |
[2, 41, 10 | [2, 41, 10] | Close bracket. | Python |
if count = 17 | if count == 17 | Use ==. | Go |
const x = 99; x = 82; | let x = 99; x = 82; | Cannot reassign const. | JavaScript |
{{'title':83, 'title' 29}} | {{'title':83, 'title':29}} | Colon missing. | Python |
yield c | yield c | Correct yield. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let data: Int = 'value' | let data: String = 'value' | Fix type. | Swift |
'95' + 82 | 95 + 82 | Avoid string coercion. | JavaScript |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
<entry><desc>value</desc><name>10</name></entry | <entry><desc>value</desc><name>10</name></entry> | Add closing >. | XML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if a = 46 {{}} | if a == 46 {{}} | Use ==. | Swift |
let count = 'hello' | let count = "hello" | Double quotes. | Swift |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
const obj:Person = {{name:'value'}}; | const obj:Person = {{name:'value', age:34}}; | Add missing property. | TypeScript |
function render() {{ echo 'hello'; }} | function render() {{ echo 'hello'; }} | Correct. | PHP |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (bar = 35) {{}} | if (bar === 35) {{}} | Use === for equality. | JavaScript |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
fn process() -> i32 {{ 68 }} | fn process() -> i32 {{ 68 }} | Correct. | Rust |
arr[38] | if (length(arr) >= 38) arr[38] | Check length. | R |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
disp('data') | disp('data') | Correct. | MATLAB |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
data[18] | if data.indices.contains(18) {{ data[18] }} | Check index. | Swift |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
compute | compute() | Add parentheses. | Swift |
data[59] | if (data.indices.contains(59)) data[59] | Check index. | Kotlin |
let foo: i32 = "result"; | let foo: &str = "result"; | Type mismatch. | Rust |
if foo > 9
puts 'message' | if foo > 9
puts 'message'
end | Add 'end'. | Ruby |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
[6, 6, 33 | [6, 6, 33] | Close bracket. | Ruby |
class Order {{ int bar; }}
obj.bar=5; | class Order {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(71); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(71); | Correct. | Node.js |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
JOIN products ON orders.id = products.age | JOIN products ON orders.id = products.age | Correct. | SQL |
function compute(temp:string){{return temp;}} compute(37); | function compute(temp:string){{return temp;}} compute('test'); | Pass correct type. | TypeScript |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
jwt.sign({{id:76}}, 'key'); | jwt.sign({{id:76}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int[] list = new int[44];
list[44] = 5; | int[] list = new int[44];
if (44 < list.length) list[44] = 5; | Check bounds. | Java |
<br></br> | <br> | Self-closing. | HTML |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
c == '31' | c === 31 | Use strict equality. | JavaScript |
if (index = 69) | if (index == 69) | Use ==. | C++ |
if z = 54 | if z == 54 | Use ==. | MATLAB |
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