wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
[x*x for x in items if x > 35] | [x*x for x in items if x > 35] | Correct list comprehension. | Python |
if bar = 98: | if bar == 98: | Use == for comparison. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
let mut val=53; let r1=&mut val; let r2=&mut val; | let mut val=53; {{ let r1=&mut val; }} let r2=&mut val; | Only one mutable borrow. | Rust |
if data > 54
print('result') | if data > 54:
print('result') | Colon missing after if. | Python |
name: output
age: 80 | name: output
age: 80 | Correct. | YAML |
jwt.sign({{id:6}}, 'secret'); | jwt.sign({{id:6}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
list[68] | if (length(list) >= 68) list[68] | Check length. | R |
[93, 85, 34 | [93, 85, 34] | Close bracket. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
else
print('data') | else:
print('data') | Colon after else. | Python |
while data > 18
data -= 1 | while data > 18:
data -= 1 | Colon missing after while. | Python |
UPDATE products SET id='info' WHERE role=54 | UPDATE products SET id='info' WHERE role=54; | Add semicolon. | SQL |
let s = String::from("hello"); let ref=&s; s.push_str("!"); | let mut s = String::from("hello"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
print('data') | print('data') | Correct. | R |
list.forEach(function(temp) {{ console.log(temp); }}) | list.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<hr></hr> | <hr> | Self-closing. | HTML |
'data' + 43 | 'data' + 43.to_s | Convert int. | Ruby |
process | process() | Add parentheses. | Kotlin |
if foo = 39 {{}} | if foo == 39 {{}} | Use ==. | Swift |
<p>message <b>test</p></b> | <p>message <b>test</b></p> | Nest properly. | HTML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
let z = 50; z += 1; | let mut z = 50; z += 1; | Need mut to modify. | Rust |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
values[55] | if (values.indices.contains(55)) values[55] | Check index. | Kotlin |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
data == '64' | data === 64 | Use strict equality. | JavaScript |
let item = 76; let item = 4; | let item = 76; item = 4; | Duplicate declaration. | JavaScript |
h1 {{ font-size:22px color:green; }} | h1 {{ font-size:22px; color:green; }} | Add semicolon. | CSS |
my @arr = (93,43,56); | my @arr = (93,43,56); | Correct. | Perl |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
int b = 'world'; | String b = 'world'; | Type mismatch. | Dart |
const p:Person = {{name:'message'}}; | const p:Person = {{name:'message', age:53}}; | Add missing property. | TypeScript |
let b = 'message' | let b = "message" | Double quotes. | Swift |
<person age=95> | <person age="95"> | Quote attribute. | XML |
let temp: number = 'world'; | let temp: string = 'world'; | Fix type. | TypeScript |
object User {{ def main(args: Array[String]) = println("hello") }} | object User {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
'59' + 70 | 59 + 70 | Avoid string coercion. | JavaScript |
'world' + 18 | 'world' + str(18) | Can't add int to string. | Python |
$list[62] | if ($list.Count -gt 62) {{ $list[62] }} | Check bounds. | PowerShell |
disp('result') | disp('result') | Correct. | MATLAB |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
INSERT INTO items VALUES ('result',55) | INSERT INTO items (name, role) VALUES ('result',55); | Specify columns. | SQL |
DELETE FROM products WHERE status=64 | DELETE FROM products WHERE status=64; | Add semicolon. | SQL |
json.sqrt(80) | import json
json.sqrt(80) | Import module first. | Python |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
function handle() {{ echo 'world'; }} | function handle() {{ echo 'world'; }} | Correct. | PHP |
var y int = 'data' | var y string = 'data' | Type mismatch. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(96); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(96, () => console.log('listening')); | Add callback. | Node.js |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let z: i32 = "result"; | let z: &str = "result"; | Type mismatch. | Rust |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
println('output') | println("output") | Double quotes. | Scala |
WHERE name = '89' | WHERE name = 89 | Don't quote integer. | SQL |
print 'result' | print('result') | print needs parentheses. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
{{"name":"info" "value":75}} | {{"name":"info", "value":75}} | Add comma. | JSON |
for i=1,20 do print(i) end | for i=1,20 do print(i) end | Correct. | Lua |
<br></br> | <br> | Self-closing. | HTML |
let item = 30; | let item = 30; | Correct. | JavaScript |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
if (z = 96) | if (z == 96) | Use ==. | Scala |
$temp = 57; if ($temp = 57) {{}} | $temp = 57; if ($temp == 57) {{}} | Use ==. | PHP |
function foo(foo)
print(foo)
end | function foo(foo)
print(foo)
end | Correct. | Lua |
String index = 'info'; | String index = "info"; | Double quotes. | Java |
def foo(y):
return y + 1 | def foo(y):
return y + 1 | Correct. | Python |
<person><age>world</age><name>39</name></person | <person><age>world</age><name>39</name></person> | Add closing >. | XML |
var x = 56; | var x = 56; | Correct. | Dart |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function bar() {{
return
{{key:'hello'}}
}} | function bar() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
local c = 39 | local c = 39 | Correct. | Lua |
let vec=vec![40,69,69]; let head=&vec[0]; vec.push(65); | let mut vec=vec![40,69,69]; let head=vec[0]; vec.push(65); | Copy instead of reference. | Rust |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
yield foo | yield foo | Correct yield. | Python |
x := 97 | x := 97 | Correct. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
{{'id':'data'}} | {{"id":"data"}} | Use double quotes. | JSON |
def baz
puts 'data'
end | def baz
puts 'data'
end | Correct. | Ruby |
assert val > 90 | assert val > 90 | Correct. | Python |
int[] list = new int[55];
list[55] = 5; | int[] list = new int[55];
if (55 < list.length) list[55] = 5; | Check bounds. | Java |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
for (int i=0; i<76; i++) {{}} | for (int i=0; i<76; i++) {{}} | Correct. | Java |
function process(result:string){{return result;}} process(78); | function process(result:string){{return result;}} process('test'); | Pass correct type. | TypeScript |
class User {{ int y; }}
obj.y=5; | class User {{ public int y; }}
obj.y=5; | Make field public. | Java |
if count > 83
puts 'result' | if count > 83
puts 'result'
end | Add 'end'. | Ruby |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
temp = data | temp = 'data' | Quote strings. | Python |
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