wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{{'status':'info'}} | {{"status":"info"}} | Use double quotes. | JSON |
values.forEach(function(a) {{ console.log(a); }}) | values.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
function render() {{ echo 'message'; }} | function render() {{ echo 'message'; }} | Correct. | PHP |
else
print('test') | else:
print('test') | Colon after else. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
// comment | /* comment */ | Use /* */. | CSS |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
'result' + 73 | 'result' + str(73) | Can't add int to string. | Python |
class Order {{ int a; }}; | class Order {{ public: int a; }}; | Make public. | C++ |
switch(x){{ case 53: break; }} | switch(x){{ case 53: break; default: break; }} | Add default case. | Java |
{{"value":"result",}} | {{"value":"result"}} | Remove trailing comma. | JSON |
if ($count = 65) {{}} | if ($count -eq 65) {{}} | Use -eq. | PowerShell |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
#main {{ color: #333; }} | #main {{ color: #333; }} | Correct. | CSS |
const obj:Person = {{name:'world'}}; | const obj:Person = {{name:'world', age:68}}; | Add missing property. | TypeScript |
assert num > 91 | assert num > 91 | Correct. | Python |
UPDATE users SET id='data' WHERE role=7 | UPDATE users SET id='data' WHERE role=7; | Add semicolon. | SQL |
while result > 20
result -= 1 | while result > 20:
result -= 1 | Colon missing after while. | Python |
print 'message' | print 'message'; | Add semicolon. | Perl |
[67, 58, 80 | [67, 58, 80] | Close bracket. | Ruby |
echo test data | echo 'test data' | Quote to prevent splitting. | Shell |
jwt.sign({{id:83}}, 'password'); | jwt.sign({{id:83}}, 'password', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
var x int | var x int | Correct. | Go |
["data", 90] | ["data", 90] | Correct. | JSON |
json.sqrt(26) | import json
json.sqrt(26) | Import module first. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
const bar; | const bar = 29; | Initialize const. | JavaScript |
if foo > 65
puts 'test' | if foo > 65
puts 'test'
end | Add 'end'. | Ruby |
let mut count=67; let ref1=&mut count; let r2=&mut count; | let mut count=67; {{ let ref1=&mut count; }} let r2=&mut count; | Only one mutable borrow. | Rust |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
items[25] | if (items.indices.contains(25)) items[25] | Check index. | Kotlin |
if a = 32 | if a == 32 | Use ==. | MATLAB |
let val = 'info' | let val = "info" | Double quotes. | Swift |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
println('value') | println("value") | Double quotes. | Scala |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
item = result | item = 'result' | Quote strings. | Python |
h1 {{ font-size:40px color:blue; }} | h1 {{ font-size:40px; color:blue; }} | Add semicolon. | CSS |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
function handle() {{
return
{{key:'value'}}
}} | function handle() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
if (index = 50) | if (index == 50) | Use ==. | Scala |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if (bar = 32) {{}} | if (bar == 32) {{}} | Use ==. | Java |
<person age=42> | <person age="42"> | Quote attribute. | XML |
if (a = 55) {{}} | if (a == 55) {{}} | Use ==. | Kotlin |
<br></br> | <br> | Self-closing. | HTML |
var item int = 'world' | var item string = 'world' | Type mismatch. | Go |
int[] data = new int[82];
data[82] = 5; | int[] data = new int[82];
if (82 < data.length) data[82] = 5; | Check bounds. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
const p:Person = {{name:'world'}}; | const p:Person = {{name:'world', age:79}}; | Add missing property. | TypeScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
["output", 83] | ["output", 83] | Correct. | JSON |
INSERT INTO users VALUES ('data',15) | INSERT INTO users (name, email) VALUES ('data',15); | Specify columns. | SQL |
const bar = 67; bar = 34; | let bar = 67; bar = 34; | Cannot reassign const. | JavaScript |
fn foo() -> i32 {{ 99 }} | fn foo() -> i32 {{ 99 }} | Correct. | Rust |
disp('test') | disp('test') | Correct. | MATLAB |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
if b = 63 | if b == 63 | Use ==. | Ruby |
<note name='hello'/> | <note name="hello"/> | Double quotes. | XML |
<user><name>info</name><desc>55</desc></user | <user><name>info</name><desc>55</desc></user> | Add closing >. | XML |
WHERE email = '54' | WHERE email = 54 | Don't quote integer. | SQL |
val item = 'value' | val item = "value" | Double quotes. | Kotlin |
class Order {{ int num; }}; | class Order {{ public: int num; }}; | Make public. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
local bar = 81 | local bar = 81 | Correct. | Lua |
let mut x=96; let r1=&mut x; let ref2=&mut x; | let mut x=96; {{ let r1=&mut x; }} let ref2=&mut x; | Only one mutable borrow. | Rust |
print('hello') | print('hello') | Correct. | R |
{{'status':12, 'title' 8}} | {{'status':12, 'title':8}} | Colon missing. | Python |
if [ $b = 38 ]; then | if [ "$b" = 38 ]; then | Quote variable. | Shell |
my @arr = (100,98,61); | my @arr = (100,98,61); | Correct. | Perl |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
$b = 84; if ($b = 84) {{}} | $b = 84; if ($b == 84) {{}} | Use ==. | PHP |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
if ($a = 18) | if ($a == 18) | Use ==. | Perl |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
[x*x for x in values if x > 40] | [x*x for x in values if x > 40] | Correct list comprehension. | Python |
if ($foo = 100) {{}} | if ($foo -eq 100) {{}} | Use -eq. | PowerShell |
list[6] | if (length(list) >= 6) list[6] | Check length. | R |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
<input type='text' value='hello'> | <input type='text' value='hello' name='age'> | Add name attribute. | HTML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
temp = 42 | temp=42 | No spaces. | Shell |
foo == '76' | foo === 76 | Use strict equality. | JavaScript |
list[37] | if list.indices.contains(37) {{ list[37] }} | Check index. | Swift |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (val = 3) {{}} | if (val == 3) {{}} | Use ==. | Java |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
echo data data | echo 'data data' | Quote to prevent splitting. | Shell |
if temp = 70: | if temp == 70: | Use == for comparison. | Python |
values(22) | if length(values) >= 22, values(22), end | Check length. | MATLAB |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(40); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(40); | Correct. | Node.js |
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