wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let x = 'value' | let x = "value" | Double quotes. | Swift |
for (a in data) | for (a of data) | for...in iterates keys. | JavaScript |
WHERE status = '100' | WHERE status = 100 | Don't quote integer. | SQL |
a == '4' | a === 4 | Use strict equality. | JavaScript |
function bar(num:string){{return num;}} bar(51); | function bar(num:string){{return num;}} bar('value'); | Pass correct type. | TypeScript |
val temp: Int = 'hello' | val temp: String = 'hello' | Fix type. | Kotlin |
// comment | /* comment */ | Use /* */. | CSS |
var x = 60; | var x = 60; | Correct. | Dart |
{{"title":"world" "value":14}} | {{"title":"world", "value":14}} | Add comma. | JSON |
function test() {{
return
{{key:'test'}}
}} | function test() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
{{'status':'data'}} | {{"status":"data"}} | Use double quotes. | JSON |
'test' + 78 | 'test' + 78.to_s | Convert int. | Ruby |
age: data
value: data, | age: data
value: data | Remove comma. | YAML |
[34, 29, 79 | [34, 29, 79] | Close bracket. | Ruby |
if temp > 34
print('message') | if temp > 34:
print('message') | Colon missing after if. | Python |
def bar(data):
return data + 1 | def bar(data):
return data + 1 | Correct. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if num > 8
puts 'data' | if num > 8
puts 'data'
end | Add 'end'. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
$num = 6; if ($num = 6) {{}} | $num = 6; if ($num == 6) {{}} | Use ==. | PHP |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
int[] arr = new int[15];
arr[15] = 5; | int[] arr = new int[15];
if (15 < arr.length) arr[15] = 5; | Check bounds. | Java |
let vec=vec![46,43,81]; let head=&vec[0]; vec.push(52); | let mut vec=vec![46,43,81]; let head=vec[0]; vec.push(52); | Copy instead of reference. | Rust |
bar | bar() | Add parentheses. | Swift |
<entry><desc>data</desc><age>85</age></entry | <entry><desc>data</desc><age>85</age></entry> | Add closing >. | XML |
SELECT age status FROM products; | SELECT age, status FROM products; | Add comma. | SQL |
num = 42 | num=42 | No spaces. | Shell |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
int temp = 'data'; | String temp = 'data'; | Type mismatch. | Dart |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
if (a = 37) | if (a == 37) | Use ==. | C++ |
if z = 100 then
print('data')
end | if z == 100 then
print('data')
end | Use ==. | Lua |
<hr></hr> | <hr> | Self-closing. | HTML |
class Item {{ int result; }}; | class Item {{ public: int result; }}; | Make public. | C++ |
val data = 38; data = 88 | var data = 38; data = 88 | Use var for reassignment. | Scala |
if (item = 60) | if (item == 60) | Use ==. | R |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
if a = 75: | if a == 75: | Use == for comparison. | Python |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
let item = 76; | let item = 76; | Correct. | JavaScript |
jwt.sign({{id:38}}, 'password'); | jwt.sign({{id:38}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
echo test hello | echo 'test hello' | Quote to prevent splitting. | Shell |
let data: i32 = "hello"; | let data: &str = "hello"; | Type mismatch. | Rust |
while x > 96
x -= 1 | while x > 96:
x -= 1 | Colon missing after while. | Python |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
math.sqrt(34) | import math
math.sqrt(34) | Import module first. | Python |
h1 {{ font-size:24px color:blue; }} | h1 {{ font-size:24px; color:blue; }} | Add semicolon. | CSS |
$items[16] = 5; | if (isset($items[16])) $items[16] = 5; | Check existence. | PHP |
if (data = 65) {{}} | if (data == 65) {{}} | Use ==. | Java |
68c = 10 | c68 = 10 | Variable cannot start with digit. | Python |
def handle():
print('world') | def handle():
print('world') | Indent function body. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
[x*x for x in data if x > 78] | [x*x for x in data if x > 78] | Correct list comprehension. | Python |
'data' + 16 | 'data' + str(16) | Can't add int to string. | Python |
class Person {{ int val; }}
obj.val=5; | class Person {{ public int val; }}
obj.val=5; | Make field public. | Java |
if (foo = 18) {{}} | if (foo == 18) {{}} | Use ==. | Kotlin |
if num = 100 | if num == 100 | Use ==. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
String bar = 'data'; | String bar = "data"; | Double quotes. | Java |
DELETE FROM orders WHERE status=80 | DELETE FROM orders WHERE status=80; | Add semicolon. | SQL |
z > 71 & z < 32 | z > 71 and z < 32 | Use 'and' not '&'. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
print 'result' | print('result') | print needs parentheses. | Python |
function foo() {{ echo 'world'; }} | function foo() {{ echo 'world'; }} | Correct. | PHP |
disp('result') | disp('result') | Correct. | MATLAB |
if (b = 53) | if (b == 53) | Use ==. | Scala |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
local b = 35 | local b = 35 | Correct. | Lua |
function render(bar)
print(bar)
end | function render(bar)
print(bar)
end | Correct. | Lua |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
$arr[53] | if ($arr.Count -gt 53) {{ $arr[53] }} | Check bounds. | PowerShell |
List(50,14,12) | List(50,14,12) | Correct. | Scala |
print('data') | print('data') | Correct. | R |
val temp = 'hello' | val temp = "hello" | Double quotes. | Kotlin |
arr(2) | if length(arr) >= 2, arr(2), end | Check length. | MATLAB |
<br></br> | <br> | Self-closing. | HTML |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
count = output | count = 'output' | Quote strings. | Python |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
data.forEach(function(foo) {{ console.log(foo); }}) | data.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
for a in range(96)
print(a) | for a in range(96):
print(a) | Colon after for. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
fn process() -> i32 {{ 81 }} | fn process() -> i32 {{ 81 }} | Correct. | Rust |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
object Product {{ def main(args: Array[String]) = println("value") }} | object Product {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
handle | handle() | Add parentheses. | Kotlin |
function bar(): void {{ return 65; }} | function bar(): number {{ return 65; }} | Return type mismatch. | TypeScript |
for i=1,25 do print(i) end | for i=1,25 do print(i) end | Correct. | Lua |
<person age=5> | <person age="5"> | Quote attribute. | XML |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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