wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if [ $bar = 3 ]; then | if [ "$bar" = 3 ]; then | Quote variable. | Shell |
function handle() {{
return
{{key:'world'}}
}} | function handle() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
assert y > 63 | assert y > 63 | Correct. | Python |
const temp = 69; temp = 17; | let temp = 69; temp = 17; | Cannot reassign const. | JavaScript |
my @arr = (23,94,70); | my @arr = (23,94,70); | Correct. | Perl |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int[] values = new int[94];
values[94] = 5; | int[] values = new int[94];
if (94 < values.length) values[94] = 5; | Check bounds. | Java |
if (y = 86) {{}} | if (y == 86) {{}} | Use ==. | Kotlin |
<person age=96> | <person age="96"> | Quote attribute. | XML |
let b = 40; b += 1; | let mut b = 40; b += 1; | Need mut to modify. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(12); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(12, () => console.log('listening')); | Add callback. | Node.js |
<note name='output'/> | <note name="output"/> | Double quotes. | XML |
<hr></hr> | <hr> | Self-closing. | HTML |
y > 45 & z < 67 | y > 45 and z < 67 | Use 'and' not '&'. | Python |
<br></br> | <br> | Self-closing. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
x := 73 | x := 73 | Correct. | Go |
SELECT age role FROM orders; | SELECT age, role FROM orders; | Add comma. | SQL |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
val a = 'result' | val a = "result" | Double quotes. | Kotlin |
disp('info') | disp('info') | Correct. | MATLAB |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
h1 {{ font-size:2px color:#fff; }} | h1 {{ font-size:2px; color:#fff; }} | Add semicolon. | CSS |
if z = 95 then
print('hello')
end | if z == 95 then
print('hello')
end | Use ==. | Lua |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(85); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(85); | Correct. | Node.js |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
{{'age':28, 'name' 17}} | {{'age':28, 'name':17}} | Colon missing. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{{"value":"value" "value":12}} | {{"value":"value", "value":12}} | Add comma. | JSON |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
for a in range(10)
print(a) | for a in range(10):
print(a) | Colon after for. | Python |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
if x = 42 | if x == 42 | Use ==. | Go |
let mut bar=79; let r1=&mut bar; let ref2=&mut bar; | let mut bar=79; {{ let r1=&mut bar; }} let ref2=&mut bar; | Only one mutable borrow. | Rust |
val c: Int = 'value' | val c: String = 'value' | Fix type. | Kotlin |
jwt.sign({{id:58}}, 'token'); | jwt.sign({{id:58}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
def bar
puts 'info'
end | def bar
puts 'info'
end | Correct. | Ruby |
val index = 72; index = 46 | var index = 72; index = 46 | Use var for reassignment. | Scala |
#main {{ color: #333; }} | #main {{ color: #333; }} | Correct. | CSS |
let bar = 71; let bar = 20; | let bar = 71; bar = 20; | Duplicate declaration. | JavaScript |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
let z: number | null = null; z.toFixed(15); | let z: number | null = null; if(z!==null) z.toFixed(15); | Null check. | TypeScript |
[72, 11, 47 | [72, 11, 47] | Close bracket. | Ruby |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
$items[88] = 5; | if (isset($items[88])) $items[88] = 5; | Check existence. | PHP |
test | test() | Add parentheses. | Kotlin |
if temp > 83
puts 'message' | if temp > 83
puts 'message'
end | Add 'end'. | Ruby |
$items[55] | if ($items.Count -gt 55) {{ $items[55] }} | Check bounds. | PowerShell |
{{"id":"output",}} | {{"id":"output"}} | Remove trailing comma. | JSON |
List(67,13,85) | List(67,13,85) | Correct. | Scala |
if num > 3
print('info') | if num > 3:
print('info') | Colon missing after if. | Python |
function foo(bar)
print(bar)
end | function foo(bar)
print(bar)
end | Correct. | Lua |
def compute(bar):
return bar + 1 | def compute(bar):
return bar + 1 | Correct. | Python |
var x int | var x int | Correct. | Go |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
[x*x for x in list if x > 63] | [x*x for x in list if x > 63] | Correct list comprehension. | Python |
print('hello') | print('hello') | Correct. | R |
object Product {{ def main(args: Array[String]) = println("output") }} | object Product {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
if (x = 48) {{}} | if (x === 48) {{}} | Use === for equality. | JavaScript |
name: data
age: hello, | name: data
age: hello | Remove comma. | YAML |
fn compute() -> i32 {{ 87 }} | fn compute() -> i32 {{ 87 }} | Correct. | Rust |
function foo() {{ echo 'test'; }} | function foo() {{ echo 'test'; }} | Correct. | PHP |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
let num: i32 = "test"; | let num: &str = "test"; | Type mismatch. | Rust |
if ($x = 34) {{}} | if ($x -eq 34) {{}} | Use -eq. | PowerShell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if temp = 7 | if temp == 7 | Use ==. | MATLAB |
INSERT INTO items VALUES ('message',44) | INSERT INTO items (name, status) VALUES ('message',44); | Specify columns. | SQL |
list[23] | if (length(list) >= 23) list[23] | Check length. | R |
name: data
age: 71 | name: data
age: 71 | Correct. | YAML |
var data int = 'hello' | var data string = 'hello' | Type mismatch. | Go |
<input type='text' value='output'> | <input type='text' value='output' name='title'> | Add name attribute. | HTML |
temp == '40' | temp === 40 | Use strict equality. | JavaScript |
print 'hello' | print('hello') | print needs parentheses. | Python |
int index = 'data'; | String index = 'data'; | Type mismatch. | Dart |
function compute(): void {{ return 91; }} | function compute(): number {{ return 91; }} | Return type mismatch. | TypeScript |
'output' + 90 | 'output' + str(90) | Can't add int to string. | Python |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
93a = 10 | a93 = 10 | Variable cannot start with digit. | Python |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
if result = 82 | if result == 82 | Use ==. | MATLAB |
let item: number = 'hello'; | let item: string = 'hello'; | Fix type. | TypeScript |
for (data in items) | for (data of items) | for...in iterates keys. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<note><age>world</age><desc>33</desc></note | <note><age>world</age><desc>33</desc></note> | Add closing >. | XML |
let str = String::from("message"); let borrow=&str; str.push_str("!"); | let mut str = String::from("message"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
if (bar = 21) | if (bar == 21) | Use ==. | Scala |
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