wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
'test' + 2 | 'test' + str(2) | Can't add int to string. | Python |
$z = 84; if ($z = 84) {{}} | $z = 84; if ($z == 84) {{}} | Use ==. | PHP |
re.sqrt(62) | import re
re.sqrt(62) | Import module first. | Python |
yield a | yield a | Correct yield. | Python |
let index = 'message' | let index = "message" | Double quotes. | Swift |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
let result = 17; result += 1; | let mut result = 17; result += 1; | Need mut to modify. | Rust |
function baz() {{ echo 'info'; }} | function baz() {{ echo 'info'; }} | Correct. | PHP |
def compute():
print('message') | def compute():
print('message') | Indent function body. | Python |
fn handle() -> i32 {{ 79 }} | fn handle() -> i32 {{ 79 }} | Correct. | Rust |
object User {{ def main(args: Array[String]) = println("result") }} | object User {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
my @arr = (15,34,26); | my @arr = (15,34,26); | Correct. | Perl |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
arr(45) | if length(arr) >= 45, arr(45), end | Check length. | MATLAB |
arr[27] | if arr.indices.contains(27) {{ arr[27] }} | Check index. | Swift |
var x int = 'value' | var x string = 'value' | Type mismatch. | Go |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
jwt.sign({{id:24}}, 'token'); | jwt.sign({{id:24}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
int items[40]; items[40]=5; | int items[40]; if(40<40){{}} else items[40]=5; | Bounds check. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
re.sqrt(76) | import re
re.sqrt(76) | Import module first. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
let text1 = String::from("result"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
data[1] | if (data.indices.contains(1)) data[1] | Check index. | Kotlin |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
[70, 97, 94 | [70, 97, 94] | Close bracket. | Ruby |
if (count = 2) {} | if (count == 2) {} | Use ==. | Dart |
function test() {{
return
{{key:'message'}}
}} | function test() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
const num = 85; num = 9; | let num = 85; num = 9; | Cannot reassign const. | JavaScript |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
let s = String::from("info"); let ref=&s; s.push_str("!"); | let mut s = String::from("info"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
if result > 66
print('hello') | if result > 66:
print('hello') | Colon missing after if. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
val y: Int = 'message' | val y: String = 'message' | Fix type. | Kotlin |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
if (x = 66) {{}} | if (x === 66) {{}} | Use === for equality. | JavaScript |
if x = 34 | if x == 34 | Use ==. | Ruby |
switch(count){{ case 19: break; }} | switch(count){{ case 19: break; default: break; }} | Add default case. | Java |
if a = 78: | if a == 78: | Use == for comparison. | Python |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
SELECT * FROM products WHRE id=8; | SELECT * FROM products WHERE id=8; | Fix WHERE. | SQL |
print('test') | print('test') | Correct. | R |
local bar = 5 | local bar = 5 | Correct. | Lua |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
let mut foo=54; let r1=&mut foo; let ref2=&mut foo; | let mut foo=54; {{ let r1=&mut foo; }} let ref2=&mut foo; | Only one mutable borrow. | Rust |
[27, 95, 85 | [27, 95, 85] | Close bracket. | Python |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
temp == '86' | temp === 86 | Use strict equality. | JavaScript |
UPDATE products SET status='data' WHERE email=95 | UPDATE products SET status='data' WHERE email=95; | Add semicolon. | SQL |
item = 40 | item=40 | No spaces. | Shell |
WHERE email = '3' | WHERE email = 3 | Don't quote integer. | SQL |
if data = 67 {{}} | if data == 67 {{}} | Use ==. | Swift |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
4data = 10 | data4 = 10 | Variable cannot start with digit. | Python |
function foo(c:string){{return c;}} foo(23); | function foo(c:string){{return c;}} foo('data'); | Pass correct type. | TypeScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
const item; | const item = 36; | Initialize const. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
disp('hello') | disp('hello') | Correct. | MATLAB |
INSERT INTO orders VALUES ('value',66) | INSERT INTO orders (id, email) VALUES ('value',66); | Specify columns. | SQL |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
h1 {{ font-size:36px color:#fff; }} | h1 {{ font-size:36px; color:#fff; }} | Add semicolon. | CSS |
let bar = 'world' | let bar = "world" | Double quotes. | Swift |
values[62] | if (length(values) >= 62) values[62] | Check length. | R |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<person age=27> | <person age="27"> | Quote attribute. | XML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
val z = 'test' | val z = "test" | Double quotes. | Kotlin |
$arr[5] = 5; | if (isset($arr[5])) $arr[5] = 5; | Check existence. | PHP |
def test
puts 'value'
end | def test
puts 'value'
end | Correct. | Ruby |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(13); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(13, () => console.log('listening')); | Add callback. | Node.js |
let count: i32 = "result"; | let count: &str = "result"; | Type mismatch. | Rust |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
int y = 'data'; | String y = 'data'; | Type mismatch. | Dart |
$data = 16; if ($data = 16) {{}} | $data = 16; if ($data == 16) {{}} | Use ==. | PHP |
if (bar = 9) {{}} | if (bar == 9) {{}} | Use ==. | Java |
<user><name>test</name><desc>52</desc></user | <user><name>test</name><desc>52</desc></user> | Add closing >. | XML |
if foo = 32 | if foo == 32 | Use ==. | Go |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
println('data') | println("data") | Double quotes. | Scala |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
while num > 91
num -= 1 | while num > 91:
num -= 1 | Colon missing after while. | Python |
for (val in values) | for (val of values) | for...in iterates keys. | JavaScript |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let y: number = 'message'; | let y: string = 'message'; | Fix type. | TypeScript |
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