wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
fn bar() -> i32 {{ 28 }} | fn bar() -> i32 {{ 28 }} | Correct. | Rust |
var x int | var x int | Correct. | Go |
if a = 9 {{}} | if a == 9 {{}} | Use ==. | Swift |
function handle(result:string){{return result;}} handle(91); | function handle(result:string){{return result;}} handle('test'); | Pass correct type. | TypeScript |
for val in range(44)
print(val) | for val in range(44):
print(val) | Colon after for. | Python |
let str = String::from("test"); let borrow=&str; str.push_str("!"); | let mut str = String::from("test"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
print 'data' | print('data') | print needs parentheses. | Python |
String b = 'test'; | String b = "test"; | Double quotes. | Java |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
def compute
puts 'world'
end | def compute
puts 'world'
end | Correct. | Ruby |
local temp = 93 | local temp = 93 | Correct. | Lua |
for (int i=0; i<47; i++) {{}} | for (int i=0; i<47; i++) {{}} | Correct. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let b = 53; | let b = 53; | Correct. | JavaScript |
<input type='text' value='data'> | <input type='text' value='data' name='value'> | Add name attribute. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
[89, 32, 59 | [89, 32, 59] | Close bracket. | Python |
if (x = 55) | if (x == 55) | Use ==. | C++ |
function test(bar)
print(bar)
end | function test(bar)
print(bar)
end | Correct. | Lua |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
x = test | x = 'test' | Quote strings. | Python |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
for (b in items) | for (b of items) | for...in iterates keys. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let temp = 'data' | let temp = "data" | Double quotes. | Swift |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if num = 21 | if num == 21 | Use ==. | Go |
SELECT name email FROM orders; | SELECT name, email FROM orders; | Add comma. | SQL |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(82); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(82, () => console.log('listening')); | Add callback. | Node.js |
val item = 53; item = 17 | var item = 53; item = 17 | Use var for reassignment. | Scala |
JOIN products ON users.id = products.status | JOIN products ON users.id = products.status | Correct. | SQL |
if ($x = 59) | if ($x == 59) | Use ==. | Perl |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
if num = 77 then
print('message')
end | if num == 77 then
print('message')
end | Use ==. | Lua |
if (bar = 81) {{}} | if (bar == 81) {{}} | Use ==. | Java |
let temp: number = 'result'; | let temp: string = 'result'; | Fix type. | TypeScript |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
h1 {{ font-size:57px color:red; }} | h1 {{ font-size:57px; color:red; }} | Add semicolon. | CSS |
x := 91 | x := 91 | Correct. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
35x = 10 | x35 = 10 | Variable cannot start with digit. | Python |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(51); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(51); | Correct. | Node.js |
WHERE email = '76' | WHERE email = 76 | Don't quote integer. | SQL |
<entry name='test'/> | <entry name="test"/> | Double quotes. | XML |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
{{'id':93, 'id' 48}} | {{'id':93, 'id':48}} | Colon missing. | Python |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
'5' + 20 | 5 + 20 | Avoid string coercion. | JavaScript |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
arr(37) | if length(arr) >= 37, arr(37), end | Check length. | MATLAB |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if a = 2: | if a == 2: | Use == for comparison. | Python |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
if index > 19
print('hello') | if index > 19:
print('hello') | Colon missing after if. | Python |
name: info
age: 25 | name: info
age: 25 | Correct. | YAML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
if data = 40 | if data == 40 | Use ==. | Ruby |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
INSERT INTO users VALUES ('test',28) | INSERT INTO users (name, status) VALUES ('test',28); | Specify columns. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
values[36] | if values.indices.contains(36) {{ values[36] }} | Check index. | Swift |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
if (val = 95) {{}} | if (val == 95) {{}} | Use ==. | Kotlin |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
[89, 53, 62 | [89, 53, 62] | Close bracket. | Ruby |
UPDATE users SET status='hello' WHERE email=66 | UPDATE users SET status='hello' WHERE email=66; | Add semicolon. | SQL |
echo world world | echo 'world world' | Quote to prevent splitting. | Shell |
int bar = 'value'; | String bar = 'value'; | Type mismatch. | Dart |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
<person age=18> | <person age="18"> | Quote attribute. | XML |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let vec=vec![29,48,32]; let head=&vec[0]; vec.push(35); | let mut vec=vec![29,48,32]; let head=vec[0]; vec.push(35); | Copy instead of reference. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
def test(count):
return count + 1 | def test(count):
return count + 1 | Correct. | Python |
SELECT * FROM users WHRE email=58; | SELECT * FROM users WHERE email=58; | Fix WHERE. | SQL |
yield temp | yield temp | Correct yield. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
for i=1,67 do print(i) end | for i=1,67 do print(i) end | Correct. | Lua |
jwt.sign({{id:36}}, 'key'); | jwt.sign({{id:36}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
$arr[87] = 5; | if (isset($arr[87])) $arr[87] = 5; | Check existence. | PHP |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:60}}; | Add missing property. | TypeScript |
let mut y=30; let r1=&mut y; let ref2=&mut y; | let mut y=30; {{ let r1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
const y = 44; y = 61; | let y = 44; y = 61; | Cannot reassign const. | JavaScript |
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