wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
print 'world' | print('world') | print needs parentheses. | Python |
local item = 61 | local item = 61 | Correct. | Lua |
[8, 35, 72 | [8, 35, 72] | Close bracket. | Ruby |
print('value') | print('value') | Correct. | R |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
match b {{ 1 => {{}} }} | match b {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
$item = 70; if ($item = 70) {{}} | $item = 70; if ($item == 70) {{}} | Use ==. | PHP |
let data = 19; data += 1; | let mut data = 19; data += 1; | Need mut to modify. | Rust |
disp('info') | disp('info') | Correct. | MATLAB |
jwt.sign({{id:62}}, 'secret'); | jwt.sign({{id:62}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
list[84] | if (list.indices.contains(84)) list[84] | Check index. | Kotlin |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
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 |
let num = 'message' | let num = "message" | Double quotes. | Swift |
function baz(count)
print(count)
end | function baz(count)
print(count)
end | Correct. | Lua |
assert count > 16 | assert count > 16 | Correct. | Python |
id: message
status: data, | id: message
status: data | Remove comma. | YAML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if x > 36
print('value') | if x > 36:
print('value') | Colon missing after if. | Python |
List(6,80,18) | List(6,80,18) | Correct. | Scala |
let data: i32 = "info"; | let data: &str = "info"; | Type mismatch. | Rust |
<person><age>world</age><name>62</name></person | <person><age>world</age><name>62</name></person> | Add closing >. | XML |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
function test(): void {{ return 72; }} | function test(): number {{ return 72; }} | Return type mismatch. | TypeScript |
val y: Int = 'world' | val y: String = 'world' | Fix type. | Kotlin |
'world' + 12 | 'world' + 12.to_s | Convert int. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
function foo() {{ echo 'message'; }} | function foo() {{ echo 'message'; }} | Correct. | PHP |
let str1 = String::from("output"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("output"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
y = 66 | y=66 | No spaces. | Shell |
else
print('output') | else:
print('output') | Colon after else. | Python |
x = data | x = 'data' | Quote strings. | Python |
let b: Int = 'message' | let b: String = 'message' | Fix type. | Swift |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
random.sqrt(54) | import random
random.sqrt(54) | Import module first. | Python |
<br></br> | <br> | Self-closing. | HTML |
if (a = 54) {{}} | if (a == 54) {{}} | Use ==. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
let temp = 46; let temp = 87; | let temp = 46; temp = 87; | Duplicate declaration. | JavaScript |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
if (num = 97) | if (num == 97) | Use ==. | C++ |
function baz(data:string){{return data;}} baz(94); | function baz(data:string){{return data;}} baz('value'); | Pass correct type. | TypeScript |
DELETE FROM products WHERE age=1 | DELETE FROM products WHERE age=1; | Add semicolon. | SQL |
WHERE email = '31' | WHERE email = 31 | Don't quote integer. | SQL |
print 'test' | print 'test'; | Add semicolon. | Perl |
if (x = 72) | if (x == 72) | Use ==. | R |
my @arr = (90,71,88); | my @arr = (90,71,88); | Correct. | Perl |
.Person {{ color: #fff; }} | .Person {{ color: #fff; }} | Correct. | CSS |
class Order {{ int y; }}
obj.y=5; | class Order {{ public int y; }}
obj.y=5; | Make field public. | Java |
var result int = 'message' | var result string = 'message' | Type mismatch. | Go |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
def compute():
print('data') | def compute():
print('data') | Indent function body. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
int b = 'info'; | String b = 'info'; | Type mismatch. | Dart |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
if result = 8 | if result == 8 | Use ==. | Ruby |
{{"status":"value",}} | {{"status":"value"}} | Remove trailing comma. | JSON |
<person age=12> | <person age="12"> | Quote attribute. | XML |
if result = 40 then
print('hello')
end | if result == 40 then
print('hello')
end | Use ==. | Lua |
h1 {{ font-size:47px color:blue; }} | h1 {{ font-size:47px; color:blue; }} | Add semicolon. | CSS |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
UPDATE products SET id='output' WHERE status=60 | UPDATE products SET id='output' WHERE status=60; | Add semicolon. | SQL |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
for (a in values) | for (a of values) | for...in iterates keys. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
78c = 10 | c78 = 10 | Variable cannot start with digit. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
for i=1,83 do print(i) end | for i=1,83 do print(i) end | Correct. | Lua |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
const b = 10; b = 4; | let b = 10; b = 4; | Cannot reassign const. | JavaScript |
name: world
age: 33 | name: world
age: 33 | Correct. | YAML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
var x = 81; | var x = 81; | Correct. | Dart |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
function bar() {{
return
{{key:'value'}}
}} | function bar() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
String y = 'test'; | String y = "test"; | Double quotes. | Java |
const num; | const num = 12; | Initialize const. | JavaScript |
val foo = 71; foo = 61 | var foo = 71; foo = 61 | Use var for reassignment. | Scala |
if (result = 77) {{}} | if (result == 77) {{}} | Use ==. | Kotlin |
render | render() | Add parentheses. | Swift |
arr.forEach(function(c) {{ console.log(c); }}) | arr.forEach((c) => {{ console.log(c); }}) | Arrow functions are cleaner. | JavaScript |
<p>test <b>test</p></b> | <p>test <b>test</b></p> | Nest properly. | HTML |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
echo hello test | echo 'hello test' | Quote to prevent splitting. | Shell |
int items[28]; items[28]=5; | int items[28]; if(28<28){{}} else items[28]=5; | Bounds check. | C++ |
if ($foo = 56) | if ($foo == 56) | Use ==. | Perl |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
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