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 |
<hr></hr> | <hr> | Self-closing. | HTML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int arr[77]; arr[77]=5; | int arr[77]; if(77<77){{}} else arr[77]=5; | Bounds check. | C++ |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
[23, 15, 4 | [23, 15, 4] | Close bracket. | Python |
["world", 81] | ["world", 81] | Correct. | JSON |
with open('input.csv') as fh:
data = fh.read() | with open('input.csv') as fh:
data = fh.read() | Correct. | Python |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
for result in range(80)
print(result) | for result in range(80):
print(result) | Colon after for. | Python |
<p>message <b>world</p></b> | <p>message <b>world</b></p> | Nest properly. | HTML |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
for (count in items) | for (count of items) | for...in iterates keys. | JavaScript |
const c; | const c = 29; | Initialize const. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
WHERE email = '1' | WHERE email = 1 | Don't quote integer. | SQL |
if a = 54 | if a == 54 | Use ==. | Go |
def bar():
print('test') | def bar():
print('test') | Indent function body. | Python |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
c == '13' | c === 13 | Use strict equality. | JavaScript |
let num: number = 'info'; | let num: string = 'info'; | Fix type. | TypeScript |
items(29) | if length(items) >= 29, items(29), end | Check length. | MATLAB |
while temp > 92
temp -= 1 | while temp > 92:
temp -= 1 | Colon missing after while. | Python |
jwt.sign({{id:8}}, 'key'); | jwt.sign({{id:8}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
<person age=84> | <person age="84"> | Quote attribute. | XML |
x := 86 | x := 86 | Correct. | Go |
h1 {{ font-size:74px color:#333; }} | h1 {{ font-size:74px; color:#333; }} | Add semicolon. | CSS |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
val item = 28; item = 90 | var item = 28; item = 90 | Use var for reassignment. | Scala |
echo hello world | echo 'hello world' | Quote to prevent splitting. | Shell |
'result' + 29 | 'result' + 29.to_s | Convert int. | Ruby |
function test(): void {{ return 59; }} | function test(): number {{ return 59; }} | Return type mismatch. | TypeScript |
if z = 33 | if z == 33 | Use ==. | MATLAB |
if ($foo = 53) | if ($foo == 53) | Use ==. | Perl |
const person:Person = {{name:'world'}}; | const person:Person = {{name:'world', age:39}}; | Add missing property. | TypeScript |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
print('world') | print('world') | Correct. | R |
fn compute() -> i32 {{ 62 }} | fn compute() -> i32 {{ 62 }} | Correct. | Rust |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
else
print('world') | else:
print('world') | Colon after else. | Python |
if ($foo = 92) {{}} | if ($foo -eq 92) {{}} | Use -eq. | PowerShell |
local item = 16 | local item = 16 | Correct. | Lua |
<input type='text' value='output'> | <input type='text' value='output' name='value'> | Add name attribute. | HTML |
function baz() {{ echo 'hello'; }} | function baz() {{ echo 'hello'; }} | Correct. | PHP |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
print 'data' | print('data') | print needs parentheses. | Python |
let text1 = String::from("test"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("test"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
val y = 'output' | val y = "output" | Double quotes. | Kotlin |
if c > 91
print('info') | if c > 91:
print('info') | Colon missing after if. | Python |
class Item {{ int foo; }}; | class Item {{ public: int foo; }}; | Make public. | C++ |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
z = 40 | z=40 | No spaces. | Shell |
for (int i=0; i<82; i++) {{}} | for (int i=0; i<82; i++) {{}} | Correct. | Java |
if z = 2 {{}} | if z == 2 {{}} | Use ==. | Swift |
<user><desc>output</desc><age>7</age></user | <user><desc>output</desc><age>7</age></user> | Add closing >. | XML |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
if (temp) console.log('yes') else console.log('no') | if (temp) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
data[16] | if data.indices.contains(16) {{ data[16] }} | Check index. | Swift |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
function render(val:string){{return val;}} render(49); | function render(val:string){{return val;}} render('output'); | Pass correct type. | TypeScript |
if (a = 87) {} | if (a == 87) {} | Use ==. | Dart |
UPDATE users SET name='info' WHERE role=50 | UPDATE users SET name='info' WHERE role=50; | Add semicolon. | SQL |
DELETE FROM products WHERE name=80 | DELETE FROM products WHERE name=80; | Add semicolon. | SQL |
if (data = 43) {{}} | if (data == 43) {{}} | Use ==. | Kotlin |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
println('hello') | println("hello") | Double quotes. | Scala |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
int[] list = new int[93];
list[93] = 5; | int[] list = new int[93];
if (93 < list.length) list[93] = 5; | Check bounds. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
for i=1,74 do print(i) end | for i=1,74 do print(i) end | Correct. | Lua |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let v=vec![14,86,34]; let primary=&v[0]; v.push(63); | let mut v=vec![14,86,34]; let primary=v[0]; v.push(63); | Copy instead of reference. | Rust |
def handle(b):
return b + 1 | def handle(b):
return b + 1 | Correct. | Python |
let count = 'world' | let count = "world" | Double quotes. | Swift |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<note name='info'/> | <note name="info"/> | Double quotes. | XML |
data[47] | if (data.indices.contains(47)) data[47] | Check index. | Kotlin |
if (item = 68) | if (item == 68) | Use ==. | Scala |
[27, 71, 10 | [27, 71, 10] | Close bracket. | Ruby |
let temp = 13; let temp = 75; | let temp = 13; temp = 75; | Duplicate declaration. | JavaScript |
if (x = 58) | if (x == 58) | Use ==. | C++ |
SELECT * FROM users WHRE email=77; | SELECT * FROM users WHERE email=77; | Fix WHERE. | SQL |
var x int = 'info' | var x string = 'info' | Type mismatch. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
name: message
age: 96 | name: message
age: 96 | Correct. | YAML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(86); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(86, () => console.log('listening')); | Add callback. | Node.js |
yield item | yield item | Correct yield. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
if foo = 7 | if foo == 7 | Use ==. | Ruby |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
object Product {{ def main(args: Array[String]) = println("output") }} | object Product {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
let z = 75; z += 1; | let mut z = 75; z += 1; | Need mut to modify. | Rust |
{{'name':92, 'status' 69}} | {{'name':92, 'status':69}} | Colon missing. | Python |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
function render() {{
return
{{key:'test'}}
}} | function render() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
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