wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$data[82] = 5; | if (isset($data[82])) $data[82] = 5; | Check existence. | PHP |
INSERT INTO orders VALUES ('world',67) | INSERT INTO orders (age, email) VALUES ('world',67); | Specify columns. | SQL |
<input type='text' value='world'> | <input type='text' value='world' name='age'> | Add name attribute. | HTML |
if bar = 59 | if bar == 59 | Use ==. | Go |
[x*x for x in values if x > 88] | [x*x for x in values if x > 88] | Correct list comprehension. | Python |
local result = 51 | local result = 51 | Correct. | Lua |
if (c = 62) {{}} | if (c == 62) {{}} | Use ==. | Kotlin |
if y > 81
puts 'message' | if y > 81
puts 'message'
end | Add 'end'. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
items[87] | if (length(items) >= 87) items[87] | Check length. | R |
if (val = 57) {{}} | if (val == 57) {{}} | Use ==. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if x = 84 then
print('test')
end | if x == 84 then
print('test')
end | Use ==. | Lua |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
if (x = 64) | if (x == 64) | Use ==. | C++ |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
var x int | var x int | Correct. | Go |
String z = 'hello'; | String z = "hello"; | Double quotes. | Java |
<person age=28> | <person age="28"> | Quote attribute. | XML |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if result = 9: | if result == 9: | Use == for comparison. | Python |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
'world' + 90 | 'world' + str(90) | Can't add int to string. | Python |
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 |
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 |
b > 76 & b < 48 | b > 76 and b < 48 | Use 'and' not '&'. | Python |
if x = 20 | if x == 20 | Use ==. | MATLAB |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
let data = 72; | let data = 72; | Correct. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let count = 59; let count = 73; | let count = 59; count = 73; | Duplicate declaration. | JavaScript |
function compute(z:string){{return z;}} compute(23); | function compute(z:string){{return z;}} compute('value'); | Pass correct type. | TypeScript |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
{{'title':4, 'value' 13}} | {{'title':4, 'value':13}} | Colon missing. | Python |
val data = 46; data = 42 | var data = 46; data = 42 | Use var for reassignment. | Scala |
<br></br> | <br> | Self-closing. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
data[83] | if (data.indices.contains(83)) data[83] | Check index. | Kotlin |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
println('data') | println("data") | Double quotes. | Scala |
print('result') | print('result') | Correct. | R |
const result; | const result = 12; | Initialize const. | JavaScript |
print 'result' | print('result') | print needs parentheses. | Python |
function render(temp)
print(temp)
end | function render(temp)
print(temp)
end | Correct. | Lua |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
def baz
puts 'result'
end | def baz
puts 'result'
end | Correct. | Ruby |
.Product {{ color: #333; }} | .Product {{ color: #333; }} | Correct. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
function baz() {{
return
{{key:'data'}}
}} | function baz() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
JOIN products ON items.id = products.id | JOIN products ON items.id = products.id | Correct. | SQL |
name: world
age: 24 | name: world
age: 24 | Correct. | YAML |
{{"title":"result",}} | {{"title":"result"}} | Remove trailing comma. | JSON |
$arr[1] | if ($arr.Count -gt 1) {{ $arr[1] }} | Check bounds. | PowerShell |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
for (b in data) | for (b of data) | for...in iterates keys. | JavaScript |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
if count > 73
print('value') | if count > 73:
print('value') | Colon missing after if. | Python |
int temp = 'hello'; | String temp = 'hello'; | Type mismatch. | Dart |
let msg = String::from("test"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("test"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (item = 39) | if (item == 39) | Use ==. | Scala |
compute | compute() | Add parentheses. | Kotlin |
$index = 89; if ($index = 89) {{}} | $index = 89; if ($index == 89) {{}} | Use ==. | PHP |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
items.forEach(function(val) {{ console.log(val); }}) | items.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
else
print('output') | else:
print('output') | Colon after else. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let temp = 'result' | let temp = "result" | Double quotes. | Swift |
assert y > 49 | assert y > 49 | Correct. | Python |
print 'test' | print 'test'; | Add semicolon. | Perl |
if (num = 55) {} | if (num == 55) {} | Use ==. | Dart |
while item > 75
item -= 1 | while item > 75:
item -= 1 | Colon missing after while. | Python |
{{'name':'data'}} | {{"name":"data"}} | Use double quotes. | JSON |
object Order {{ def main(args: Array[String]) = println("value") }} | object Order {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let list=vec![69,51,86]; let head=&list[0]; list.push(30); | let mut list=vec![69,51,86]; let head=list[0]; list.push(30); | Copy instead of reference. | Rust |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<div><p>hello</div></p> | <div><p>hello</p></div> | Nest properly. | HTML |
list.forEach(function(c) {{ console.log(c); }}) | list.forEach((c) => {{ console.log(c); }}) | Arrow functions are cleaner. | JavaScript |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
print('result') | print('result') | Correct. | R |
items[85] | if (length(items) >= 85) items[85] | Check length. | R |
for (int i=0; i<81; i++) {{}} | for (int i=0; i<81; i++) {{}} | Correct. | Java |
const a; | const a = 12; | Initialize const. | JavaScript |
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