wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
var a int = 'result' | var a string = 'result' | Type mismatch. | Go |
my @arr = (22,77,84); | my @arr = (22,77,84); | Correct. | Perl |
if b = 35 | if b == 35 | Use ==. | Ruby |
$items[23] = 5; | if (isset($items[23])) $items[23] = 5; | Check existence. | PHP |
val = data | val = 'data' | Quote strings. | Python |
h1 {{ font-size:72px color:red; }} | h1 {{ font-size:72px; color:red; }} | Add semicolon. | CSS |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
// comment | /* comment */ | Use /* */. | CSS |
bar == '20' | bar === 20 | Use strict equality. | JavaScript |
while data > 85
data -= 1 | while data > 85:
data -= 1 | Colon missing after while. | Python |
let b: Int = 'hello' | let b: String = 'hello' | Fix type. | Swift |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
jwt.sign({{id:70}}, 'key'); | jwt.sign({{id:70}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
name: result
age: 12 | name: result
age: 12 | Correct. | YAML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<p>result <b>world</p></b> | <p>result <b>world</b></p> | Nest properly. | HTML |
SELECT * FROM items WHRE age=73; | SELECT * FROM items WHERE age=73; | Fix WHERE. | SQL |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
var x int | var x int | Correct. | Go |
print 'data' | print 'data'; | Add semicolon. | Perl |
'message' + 48 | 'message' + str(48) | Can't add int to string. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
print('info') | print('info') | Correct. | R |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
let c: i32 = "message"; | let c: &str = "message"; | Type mismatch. | Rust |
List(63,15,49) | List(63,15,49) | Correct. | Scala |
DELETE FROM items WHERE status=28 | DELETE FROM items WHERE status=28; | Add semicolon. | SQL |
for num in range(85)
print(num) | for num in range(85):
print(num) | Colon after for. | Python |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
let c: number | null = null; c.toFixed(82); | let c: number | null = null; if(c!==null) c.toFixed(82); | Null check. | TypeScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
#content {{ color: blue; }} | #content {{ color: blue; }} | Correct. | CSS |
'26' + 47 | 26 + 47 | Avoid string coercion. | JavaScript |
function bar() {{
return
{{key:'test'}}
}} | function bar() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
["message", 23] | ["message", 23] | Correct. | JSON |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
bar | bar() | Add parentheses. | Swift |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
if ($item = 21) {{}} | if ($item -eq 21) {{}} | Use -eq. | PowerShell |
for (a in items) | for (a of items) | for...in iterates keys. | JavaScript |
if num = 69 | if num == 69 | Use ==. | MATLAB |
WHERE name = '32' | WHERE name = 32 | Don't quote integer. | SQL |
$values[85] | if ($values.Count -gt 85) {{ $values[85] }} | Check bounds. | PowerShell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (temp) console.log('yes') else console.log('no') | if (temp) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let text1 = String::from("world"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("world"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
println('message') | println("message") | Double quotes. | Scala |
[x*x for x in arr if x > 14] | [x*x for x in arr if x > 14] | Correct list comprehension. | Python |
if count > 61
puts 'data' | if count > 61
puts 'data'
end | Add 'end'. | Ruby |
local foo = 15 | local foo = 15 | Correct. | Lua |
if (index = 55) {{}} | if (index === 55) {{}} | Use === for equality. | JavaScript |
if (item = 12) {{}} | if (item == 12) {{}} | Use ==. | Kotlin |
switch(count){{ case 72: break; }} | switch(count){{ case 72: break; default: break; }} | Add default case. | Java |
function process(num)
print(num)
end | function process(num)
print(num)
end | Correct. | Lua |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
items(37) | if length(items) >= 37, items(37), end | Check length. | MATLAB |
{{'id':48, 'id' 75}} | {{'id':48, 'id':75}} | Colon missing. | Python |
math.sqrt(80) | import math
math.sqrt(80) | Import module first. | Python |
assert x > 57 | assert x > 57 | Correct. | Python |
arr[45] | if (length(arr) >= 45) arr[45] | Check length. | R |
def handle():
print('data') | def handle():
print('data') | Indent function body. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(30); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(30, () => console.log('listening')); | Add callback. | Node.js |
'hello' + 77 | 'hello' + 77.to_s | Convert int. | Ruby |
let vec=vec![64,41,79]; let primary=&vec[0]; vec.push(85); | let mut vec=vec![64,41,79]; let primary=vec[0]; vec.push(85); | Copy instead of reference. | Rust |
if ($val = 49) | if ($val == 49) | Use ==. | Perl |
if bar = 11: | if bar == 11: | Use == for comparison. | Python |
disp('world') | disp('world') | Correct. | MATLAB |
[42, 43, 84 | [42, 43, 84] | Close bracket. | Python |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
87bar = 10 | bar87 = 10 | Variable cannot start with digit. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
if (y = 59) | if (y == 59) | Use ==. | C++ |
items[73] | if items.indices.contains(73) {{ items[73] }} | Check index. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let index = 24; let index = 11; | let index = 24; index = 11; | Duplicate declaration. | JavaScript |
let y = 3; | let y = 3; | Correct. | JavaScript |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (y = 39) | if (y == 39) | Use ==. | Scala |
x > 86 & z < 25 | x > 86 and z < 25 | Use 'and' not '&'. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
let mut foo=70; let r1=&mut foo; let ref2=&mut foo; | let mut foo=70; {{ let r1=&mut foo; }} let ref2=&mut foo; | Only one mutable borrow. | Rust |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
int x = 'test'; | String x = 'test'; | Type mismatch. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(90); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(90); | Correct. | Node.js |
arr.forEach(function(item) {{ console.log(item); }}) | arr.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let text = String::from("hello"); let ref=&text; text.push_str("!"); | let mut text = String::from("hello"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
def process(temp):
return temp + 1 | def process(temp):
return temp + 1 | Correct. | Python |
INSERT INTO items VALUES ('info',94) | INSERT INTO items (name, status) VALUES ('info',94); | Specify columns. | SQL |
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