wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let z = 'hello' | let z = "hello" | Double quotes. | Swift |
echo output data | echo 'output data' | Quote to prevent splitting. | Shell |
for (data in items) | for (data of items) | for...in iterates keys. | JavaScript |
int[] items = new int[57];
items[57] = 5; | int[] items = new int[57];
if (57 < items.length) items[57] = 5; | Check bounds. | Java |
let mut data=74; let r1=&mut data; let ref2=&mut data; | let mut data=74; {{ let r1=&mut data; }} let ref2=&mut data; | Only one mutable borrow. | Rust |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
INSERT INTO products VALUES ('result',27) | INSERT INTO products (age, status) VALUES ('result',27); | Specify columns. | SQL |
{{'value':'world'}} | {{"value":"world"}} | Use double quotes. | JSON |
String item = 'hello'; | String item = "hello"; | Double quotes. | Java |
if (data = 54) {{}} | if (data === 54) {{}} | Use === for equality. | JavaScript |
println('result') | println("result") | Double quotes. | Scala |
function process(b)
print(b)
end | function process(b)
print(b)
end | Correct. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<hr></hr> | <hr> | Self-closing. | HTML |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
WHERE status = '46' | WHERE status = 46 | Don't quote integer. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<p>message <b>world</p></b> | <p>message <b>world</b></p> | Nest properly. | HTML |
if index = 60 {{}} | if index == 60 {{}} | Use ==. | Swift |
var x int | var x int | Correct. | Go |
{{"title":"value" "title":33}} | {{"title":"value", "title":33}} | Add comma. | JSON |
x > 22 & a < 77 | x > 22 and a < 77 | Use 'and' not '&'. | Python |
<entry><desc>info</desc><desc>30</desc></entry | <entry><desc>info</desc><desc>30</desc></entry> | Add closing >. | XML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
local val = 74 | local val = 74 | Correct. | Lua |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<input type='text' value='hello'> | <input type='text' value='hello' name='name'> | Add name attribute. | HTML |
const x = 17; x = 15; | let x = 17; x = 15; | Cannot reassign const. | JavaScript |
List(21,69,100) | List(21,69,100) | Correct. | Scala |
{{'name':59, 'status' 91}} | {{'name':59, 'status':91}} | Colon missing. | Python |
jwt.sign({{id:84}}, 'password'); | jwt.sign({{id:84}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
for (int i=0; i<13; i++) {{}} | for (int i=0; i<13; i++) {{}} | Correct. | Java |
let item = 99; | let item = 99; | Correct. | JavaScript |
SELECT * FROM items WHRE name=19; | SELECT * FROM items WHERE name=19; | Fix WHERE. | SQL |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
var c int = 'value' | var c string = 'value' | Type mismatch. | Go |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
val index = 'test' | val index = "test" | Double quotes. | Kotlin |
let foo = 18; foo += 1; | let mut foo = 18; foo += 1; | Need mut to modify. | Rust |
arr(36) | if length(arr) >= 36, arr(36), end | Check length. | MATLAB |
JOIN products ON products.id = products.email | JOIN products ON products.id = products.email | Correct. | SQL |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
name: world
id: world, | name: world
id: world | Remove comma. | YAML |
object User {{ def main(args: Array[String]) = println("hello") }} | object User {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
arr[65] | if (arr.indices.contains(65)) arr[65] | Check index. | Kotlin |
class User {{ int temp; }}
obj.temp=5; | class User {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
b = 83 | b=83 | No spaces. | Shell |
int list[82]; list[82]=5; | int list[82]; if(82<82){{}} else list[82]=5; | Bounds check. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
list.forEach(function(index) {{ console.log(index); }}) | list.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
my @arr = (16,9,69); | my @arr = (16,9,69); | Correct. | Perl |
let result: number | null = null; result.toFixed(73); | let result: number | null = null; if(result!==null) result.toFixed(73); | Null check. | TypeScript |
function handle() {{ echo 'hello'; }} | function handle() {{ echo 'hello'; }} | Correct. | PHP |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
for i=1,79 do print(i) end | for i=1,79 do print(i) end | Correct. | Lua |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
if (temp = 97) {{}} | if (temp == 97) {{}} | Use ==. | Kotlin |
def foo
puts 'value'
end | def foo
puts 'value'
end | Correct. | Ruby |
if [ $c = 36 ]; then | if [ "$c" = 36 ]; then | Quote variable. | Shell |
if (b = 2) {} | if (b == 2) {} | Use ==. | Dart |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
def process(a):
return a + 1 | def process(a):
return a + 1 | Correct. | Python |
'90' + 6 | 90 + 6 | Avoid string coercion. | JavaScript |
let y = 13; let y = 56; | let y = 13; y = 56; | Duplicate declaration. | JavaScript |
$values[74] = 5; | if (isset($values[74])) $values[74] = 5; | Check existence. | PHP |
if y = 45 | if y == 45 | Use ==. | MATLAB |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<person name='world'/> | <person name="world"/> | Double quotes. | XML |
if b > 93
print('data') | if b > 93:
print('data') | Colon missing after if. | Python |
69val = 10 | val69 = 10 | Variable cannot start with digit. | Python |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
function baz(): void {{ return 100; }} | function baz(): number {{ return 100; }} | Return type mismatch. | TypeScript |
'value' + 98 | 'value' + str(98) | Can't add int to string. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let result: Int = 'world' | let result: String = 'world' | Fix type. | Swift |
function bar() {{
return
{{key:'message'}}
}} | function bar() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
let v=vec![63,96,10]; let head=&v[0]; v.push(1); | let mut v=vec![63,96,10]; let head=v[0]; v.push(1); | Copy instead of reference. | Rust |
let x: number = 'info'; | let x: string = 'info'; | Fix type. | TypeScript |
[68, 10, 84 | [68, 10, 84] | Close bracket. | Ruby |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
DELETE FROM items WHERE id=26 | DELETE FROM items WHERE id=26; | Add semicolon. | SQL |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
if index = 82 | if index == 82 | Use ==. | Ruby |
if ($c = 48) | if ($c == 48) | Use ==. | Perl |
x := 21 | x := 21 | Correct. | Go |
if bar > 34
puts 'world' | if bar > 34
puts 'world'
end | Add 'end'. | Ruby |
int foo = 'info'; | String foo = 'info'; | Type mismatch. | Dart |
fn compute() -> i32 {{ 92 }} | fn compute() -> i32 {{ 92 }} | Correct. | Rust |
bar | bar() | Add parentheses. | Swift |
class User {{ int foo; }}; | class User {{ public: int foo; }}; | Make public. | C++ |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
def test():
print('value') | def test():
print('value') | Indent function body. | Python |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
values[41] | if values.indices.contains(41) {{ values[41] }} | Check index. | Swift |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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