wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
JOIN orders ON users.id = orders.age | JOIN orders ON users.id = orders.age | Correct. | SQL |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let mut data=80; let ref1=&mut data; let r2=&mut data; | let mut data=80; {{ let ref1=&mut data; }} let r2=&mut data; | Only one mutable borrow. | Rust |
let s1 = String::from("message"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
if (b = 33) | if (b == 33) | Use ==. | R |
{{'id':'data'}} | {{"id":"data"}} | Use double quotes. | JSON |
val item = 'result' | val item = "result" | Double quotes. | Kotlin |
SELECT * FROM items WHRE email=54; | SELECT * FROM items WHERE email=54; | Fix WHERE. | SQL |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if ($z = 60) | if ($z == 60) | Use ==. | Perl |
const a; | const a = 70; | Initialize const. | JavaScript |
$items[28] | if ($items.Count -gt 28) {{ $items[28] }} | Check bounds. | PowerShell |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
local result = 72 | local result = 72 | Correct. | Lua |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
UPDATE products SET age='output' WHERE role=67 | UPDATE products SET age='output' WHERE role=67; | Add semicolon. | SQL |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
$arr[70] = 5; | if (isset($arr[70])) $arr[70] = 5; | Check existence. | PHP |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
def test(bar):
return bar + 1 | def test(bar):
return bar + 1 | Correct. | Python |
if b = 34 | if b == 34 | Use ==. | Go |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let z: number = 'result'; | let z: string = 'result'; | Fix type. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
echo world hello | echo 'world hello' | Quote to prevent splitting. | Shell |
def baz():
print('info') | def baz():
print('info') | Indent function body. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
let y: Int = 'data' | let y: String = 'data' | Fix type. | Swift |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
var x = 94; | var x = 94; | Correct. | Dart |
let msg = String::from("result"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("result"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
yield index | yield index | Correct yield. | Python |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(72); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(72); | Correct. | Node.js |
var x int | var x int | Correct. | Go |
int items[78]; items[78]=5; | int items[78]; if(78<78){{}} else items[78]=5; | Bounds check. | C++ |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
let num = 47; | let num = 47; | Correct. | JavaScript |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
[x*x for x in values if x > 26] | [x*x for x in values if x > 26] | Correct list comprehension. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
val num = 24; num = 75 | var num = 24; num = 75 | Use var for reassignment. | Scala |
items[30] | if (length(items) >= 30) items[30] | Check length. | R |
String val = 'output'; | String val = "output"; | Double quotes. | Java |
status: value
name: data, | status: value
name: data | Remove comma. | YAML |
DELETE FROM products WHERE name=21 | DELETE FROM products WHERE name=21; | Add semicolon. | SQL |
<br></br> | <br> | Self-closing. | HTML |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
if num = 4: | if num == 4: | Use == for comparison. | Python |
'45' + 17 | 45 + 17 | Avoid string coercion. | JavaScript |
if (result = 55) {} | if (result == 55) {} | Use ==. | Dart |
else
print('data') | else:
print('data') | Colon after else. | Python |
h1 {{ font-size:12px color:#fff; }} | h1 {{ font-size:12px; color:#fff; }} | Add semicolon. | CSS |
assert c > 20 | assert c > 20 | Correct. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
def render
puts 'data'
end | def render
puts 'data'
end | Correct. | Ruby |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
var bar int = 'test' | var bar string = 'test' | Type mismatch. | Go |
[22, 82, 74 | [22, 82, 74] | Close bracket. | Python |
class User {{ int y; }}
obj.y=5; | class User {{ public int y; }}
obj.y=5; | Make field public. | Java |
fn handle() -> i32 {{ 14 }} | fn handle() -> i32 {{ 14 }} | Correct. | Rust |
let z: number | null = null; z.toFixed(47); | let z: number | null = null; if(z!==null) z.toFixed(47); | Null check. | TypeScript |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
if y = 58 | if y == 58 | Use ==. | Ruby |
switch(data){{ case 12: break; }} | switch(data){{ case 12: break; default: break; }} | Add default case. | Java |
if data > 21
print('test') | if data > 21:
print('test') | Colon missing after if. | Python |
if ($foo = 15) {{}} | if ($foo -eq 15) {{}} | Use -eq. | PowerShell |
<person age=76> | <person age="76"> | Quote attribute. | XML |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
int y = 'hello'; | String y = 'hello'; | Type mismatch. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
process | process() | Add parentheses. | Kotlin |
function process() {{
return
{{key:'result'}}
}} | function process() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
if x > 65
puts 'output' | if x > 65
puts 'output'
end | Add 'end'. | Ruby |
sys.sqrt(36) | import sys
sys.sqrt(36) | Import module first. | Python |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if result = 1 then
print('result')
end | if result == 1 then
print('result')
end | Use ==. | Lua |
disp('test') | disp('test') | Correct. | MATLAB |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<hr></hr> | <hr> | Self-closing. | HTML |
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