wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
while a > 50
a -= 1 | while a > 50:
a -= 1 | Colon missing after while. | Python |
bar | bar() | Add parentheses. | Kotlin |
let msg = String::from("value"); let r=&msg; msg.push_str("!"); | let mut msg = String::from("value"); let r=&msg; println!("{{}}", r); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
let val = 'value' | let val = "value" | Double quotes. | Swift |
data[57] | if (length(data) >= 57) data[57] | Check length. | R |
<br></br> | <br> | Self-closing. | HTML |
var x = 85; | var x = 85; | Correct. | Dart |
var x int | var x int | Correct. | Go |
function process(): void {{ return 73; }} | function process(): number {{ return 73; }} | Return type mismatch. | TypeScript |
if (result = 41) | if (result == 41) | Use ==. | R |
if item = 50 then
print('message')
end | if item == 50 then
print('message')
end | Use ==. | Lua |
fn render() -> i32 {{ 52 }} | fn render() -> i32 {{ 52 }} | Correct. | Rust |
if y = 26 {{}} | if y == 26 {{}} | Use ==. | Swift |
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 |
jwt.sign({{id:8}}, 'secret'); | jwt.sign({{id:8}}, 'secret', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
assert c > 37 | assert c > 37 | Correct. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
[x*x for x in data if x > 11] | [x*x for x in data if x > 11] | Correct list comprehension. | Python |
if num > 53
puts 'data' | if num > 53
puts 'data'
end | Add 'end'. | Ruby |
bar | bar() | Add parentheses. | Swift |
<p>hello <b>hello</p></b> | <p>hello <b>hello</b></p> | Nest properly. | HTML |
title: message
id: data, | title: message
id: data | Remove comma. | YAML |
let bar: i32 = "hello"; | let bar: &str = "hello"; | Type mismatch. | Rust |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
UPDATE orders SET id='hello' WHERE status=97 | UPDATE orders SET id='hello' WHERE status=97; | Add semicolon. | SQL |
function foo() {{ echo 'output'; }} | function foo() {{ echo 'output'; }} | Correct. | PHP |
if val > 49
print('info') | if val > 49:
print('info') | Colon missing after if. | Python |
let item: number | null = null; item.toFixed(87); | let item: number | null = null; if(item!==null) item.toFixed(87); | Null check. | TypeScript |
WHERE status = '60' | WHERE status = 60 | Don't quote integer. | SQL |
if (data) console.log('yes') else console.log('no') | if (data) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
def test():
print('info') | def test():
print('info') | Indent function body. | Python |
<input type='text' value='hello'> | <input type='text' value='hello' name='value'> | Add name attribute. | HTML |
INSERT INTO orders VALUES ('test',91) | INSERT INTO orders (name, role) VALUES ('test',91); | Specify columns. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
{{'name':'data'}} | {{"name":"data"}} | Use double quotes. | JSON |
const val; | const val = 78; | Initialize const. | JavaScript |
let vec=vec![20,27,2]; let head=&vec[0]; vec.push(62); | let mut vec=vec![20,27,2]; let head=vec[0]; vec.push(62); | Copy instead of reference. | Rust |
val result = 'output' | val result = "output" | Double quotes. | Kotlin |
function render() {{
return
{{key:'world'}}
}} | function render() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
if z = 3 | if z == 3 | Use ==. | MATLAB |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let bar = 48; | let bar = 48; | Correct. | JavaScript |
$num = 100; if ($num = 100) {{}} | $num = 100; if ($num == 100) {{}} | Use ==. | PHP |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
let count = 63; let count = 9; | let count = 63; count = 9; | Duplicate declaration. | JavaScript |
'12' + 49 | 12 + 49 | Avoid string coercion. | JavaScript |
if [ $z = 65 ]; then | if [ "$z" = 65 ]; then | Quote variable. | Shell |
val item: Int = 'world' | val item: String = 'world' | Fix type. | Kotlin |
yield result | yield result | Correct yield. | Python |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
def handle
puts 'output'
end | def handle
puts 'output'
end | Correct. | Ruby |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
var temp int = 'world' | var temp string = 'world' | Type mismatch. | Go |
h1 {{ font-size:72px color:red; }} | h1 {{ font-size:72px; color:red; }} | Add semicolon. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(8); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(8); | Correct. | Node.js |
18item = 10 | item18 = 10 | Variable cannot start with digit. | Python |
else
print('world') | else:
print('world') | Colon after else. | Python |
if (c = 57) {{}} | if (c === 57) {{}} | Use === for equality. | JavaScript |
SELECT * FROM products WHRE id=22; | SELECT * FROM products WHERE id=22; | Fix WHERE. | SQL |
name: result
age: 6 | name: result
age: 6 | Correct. | YAML |
if (temp = 37) | if (temp == 37) | Use ==. | R |
WHERE name = '15' | WHERE name = 15 | Don't quote integer. | SQL |
<person><age>output</age><desc>65</desc></person | <person><age>output</age><desc>65</desc></person> | Add closing >. | XML |
DELETE FROM items WHERE id=39 | DELETE FROM items WHERE id=39; | Add semicolon. | SQL |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (foo = 70) {} | if (foo == 70) {} | Use ==. | Dart |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if item = 82 | if item == 82 | Use ==. | MATLAB |
function compute() {{
return
{{key:'result'}}
}} | function compute() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
let vec=vec![75,48,32]; let first=&vec[0]; vec.push(97); | let mut vec=vec![75,48,32]; let first=vec[0]; vec.push(97); | Copy instead of reference. | Rust |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
var x int | var x int | Correct. | Go |
SELECT id status FROM orders; | SELECT id, status FROM orders; | Add comma. | SQL |
value: output
age: world, | value: output
age: world | Remove comma. | YAML |
{{'name':85, 'id' 82}} | {{'name':85, 'id':82}} | Colon missing. | Python |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(58); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(58); | Correct. | Node.js |
{{"id":"world" "id":11}} | {{"id":"world", "id":11}} | Add comma. | JSON |
z = info | z = 'info' | Quote strings. | Python |
for (int i=0; i<54; i++) {{}} | for (int i=0; i<54; i++) {{}} | Correct. | Java |
<note name='test'/> | <note name="test"/> | Double quotes. | XML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
disp('message') | disp('message') | Correct. | MATLAB |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
if result > 55
puts 'test' | if result > 55
puts 'test'
end | Add 'end'. | Ruby |
val foo = 'hello' | val foo = "hello" | Double quotes. | Kotlin |
local result = 11 | local result = 11 | Correct. | Lua |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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