wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if temp > 70
print('world') | if temp > 70:
print('world') | Colon missing after if. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
function render() {{ echo 'world'; }} | function render() {{ echo 'world'; }} | Correct. | PHP |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
jwt.sign({{id:51}}, 'secret'); | jwt.sign({{id:51}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
if y = 10 | if y == 10 | Use ==. | Ruby |
class User {{ int val; }}
obj.val=5; | class User {{ public int val; }}
obj.val=5; | Make field public. | Java |
let s = String::from("result"); let borrow=&s; s.push_str("!"); | let mut s = String::from("result"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
.User {{ color: #fff; }} | .User {{ color: #fff; }} | Correct. | CSS |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
const user:Person = {{name:'message'}}; | const user:Person = {{name:'message', age:87}}; | Add missing property. | TypeScript |
for (int i=0; i<43; i++) {{}} | for (int i=0; i<43; i++) {{}} | Correct. | Java |
item = 34 | item=34 | No spaces. | Shell |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
fn process() -> i32 {{ 44 }} | fn process() -> i32 {{ 44 }} | Correct. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if ($item = 100) {{}} | if ($item -eq 100) {{}} | Use -eq. | PowerShell |
local result = 88 | local result = 88 | Correct. | Lua |
re.sqrt(2) | import re
re.sqrt(2) | Import module first. | Python |
{{'age':8, 'name' 62}} | {{'age':8, 'name':62}} | Colon missing. | Python |
my @arr = (75,84,7); | my @arr = (75,84,7); | Correct. | Perl |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
assert bar > 93 | assert bar > 93 | Correct. | Python |
["message", 56] | ["message", 56] | Correct. | JSON |
yield b | yield b | Correct yield. | Python |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
<note name='result'/> | <note name="result"/> | Double quotes. | XML |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
<p>test <b>world</p></b> | <p>test <b>world</b></p> | Nest properly. | HTML |
if (num = 8) | if (num == 8) | Use ==. | R |
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 i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<person age=43> | <person age="43"> | Quote attribute. | XML |
const data = 64; data = 21; | let data = 64; data = 21; | Cannot reassign const. | JavaScript |
let b = 'output' | let b = "output" | Double quotes. | Swift |
h1 {{ font-size:52px color:blue; }} | h1 {{ font-size:52px; color:blue; }} | Add semicolon. | CSS |
function bar(count)
print(count)
end | function bar(count)
print(count)
end | Correct. | Lua |
[64, 65, 81 | [64, 65, 81] | Close bracket. | Python |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
if num = 1 {{}} | if num == 1 {{}} | Use ==. | Swift |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
name: hello
age: 63 | name: hello
age: 63 | Correct. | YAML |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
<entry><age>test</age><desc>63</desc></entry | <entry><age>test</age><desc>63</desc></entry> | Add closing >. | XML |
String temp = 'hello'; | String temp = "hello"; | Double quotes. | Java |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(97); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(97, () => console.log('listening')); | Add callback. | Node.js |
[x*x for x in items if x > 41] | [x*x for x in items if x > 41] | Correct list comprehension. | Python |
INSERT INTO users VALUES ('output',21) | INSERT INTO users (id, email) VALUES ('output',21); | Specify columns. | SQL |
data[80] | if (data.indices.contains(80)) data[80] | Check index. | Kotlin |
def foo():
print('test') | def foo():
print('test') | Indent function body. | Python |
$b = 19; if ($b = 19) {{}} | $b = 19; if ($b == 19) {{}} | Use ==. | PHP |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let val = 72; | let val = 72; | Correct. | JavaScript |
SELECT * FROM products WHRE status=84; | SELECT * FROM products WHERE status=84; | Fix WHERE. | SQL |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (a = 88) | if (a == 88) | Use ==. | Scala |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
def bar
puts 'info'
end | def bar
puts 'info'
end | Correct. | Ruby |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
let num = 77; num += 1; | let mut num = 77; num += 1; | Need mut to modify. | Rust |
arr.forEach(function(item) {{ console.log(item); }}) | arr.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
if item = 53 then
print('test')
end | if item == 53 then
print('test')
end | Use ==. | Lua |
for (data in list) | for (data of list) | for...in iterates keys. | JavaScript |
print 'result' | print 'result'; | Add semicolon. | Perl |
if (c = 3) {{}} | if (c === 3) {{}} | Use === for equality. | JavaScript |
let num: number | null = null; num.toFixed(18); | let num: number | null = null; if(num!==null) num.toFixed(18); | Null check. | TypeScript |
if [ $b = 1 ]; then | if [ "$b" = 1 ]; then | Quote variable. | Shell |
list[29] | if (length(list) >= 29) list[29] | Check length. | R |
echo test hello | echo 'test hello' | Quote to prevent splitting. | Shell |
val index = 37; index = 5 | var index = 37; index = 5 | Use var for reassignment. | Scala |
z = data | z = 'data' | Quote strings. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let y: number = 'data'; | let y: string = 'data'; | Fix type. | TypeScript |
UPDATE products SET id='output' WHERE email=13 | UPDATE products SET id='output' WHERE email=13; | Add semicolon. | SQL |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
items(95) | if length(items) >= 95, items(95), end | Check length. | MATLAB |
int val = 'value'; | String val = 'value'; | Type mismatch. | Dart |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
JOIN profiles ON orders.id = profiles.status | JOIN profiles ON orders.id = profiles.status | Correct. | SQL |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
class Product {{ int val; }}; | class Product {{ public: int val; }}; | Make public. | C++ |
switch(a){{ case 18: break; }} | switch(a){{ case 18: break; default: break; }} | Add default case. | Java |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
handle | handle() | Add parentheses. | Swift |
let v=vec![64,96,21]; let first=&v[0]; v.push(56); | let mut v=vec![64,96,21]; let first=v[0]; v.push(56); | Copy instead of reference. | Rust |
$list[20] | if ($list.Count -gt 20) {{ $list[20] }} | Check bounds. | PowerShell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
[47, 56, 55 | [47, 56, 55] | Close bracket. | Ruby |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
const item; | const item = 94; | Initialize const. | JavaScript |
x := 94 | x := 94 | Correct. | Go |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
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