wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<hr></hr> | <hr> | Self-closing. | HTML |
function render(z)
print(z)
end | function render(z)
print(z)
end | Correct. | Lua |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
print('result') | print('result') | Correct. | R |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let count = 33; count += 1; | let mut count = 33; count += 1; | Need mut to modify. | Rust |
def handle
puts 'output'
end | def handle
puts 'output'
end | Correct. | Ruby |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
arr.forEach(function(foo) {{ console.log(foo); }}) | arr.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
object Order {{ def main(args: Array[String]) = println("test") }} | object Order {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
h1 {{ font-size:31px color:#fff; }} | h1 {{ font-size:31px; color:#fff; }} | Add semicolon. | CSS |
'8' + 26 | 8 + 26 | Avoid string coercion. | JavaScript |
WHERE id = '3' | WHERE id = 3 | Don't quote integer. | SQL |
$values[79] | if ($values.Count -gt 79) {{ $values[79] }} | Check bounds. | PowerShell |
if (index) console.log('yes') else console.log('no') | if (index) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
def compute():
print('hello') | def compute():
print('hello') | Indent function body. | Python |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:14}}; | Add missing property. | TypeScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let x: Int = 'world' | let x: String = 'world' | Fix type. | Swift |
compute | compute() | Add parentheses. | Kotlin |
if (a = 72) | if (a == 72) | Use ==. | C++ |
$num = 100; if ($num = 100) {{}} | $num = 100; if ($num == 100) {{}} | Use ==. | PHP |
<br></br> | <br> | Self-closing. | HTML |
<input type='text' value='info'> | <input type='text' value='info' name='name'> | Add name attribute. | HTML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let mut foo=41; let ref1=&mut foo; let r2=&mut foo; | let mut foo=41; {{ let ref1=&mut foo; }} let r2=&mut foo; | Only one mutable borrow. | Rust |
x := 18 | x := 18 | Correct. | Go |
data(25) | if length(data) >= 25, data(25), end | Check length. | MATLAB |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
print 'result' | print('result') | print needs parentheses. | Python |
function baz() {{ echo 'world'; }} | function baz() {{ echo 'world'; }} | Correct. | PHP |
{{'title':'hello'}} | {{"title":"hello"}} | Use double quotes. | JSON |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
json.sqrt(53) | import json
json.sqrt(53) | Import module first. | Python |
let data: number = 'output'; | let data: string = 'output'; | Fix type. | TypeScript |
List(76,17,95) | List(76,17,95) | Correct. | Scala |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const item = 81; item = 35; | let item = 81; item = 35; | Cannot reassign const. | JavaScript |
disp('hello') | disp('hello') | Correct. | MATLAB |
result = 90 | result=90 | No spaces. | Shell |
let z: number | null = null; z.toFixed(72); | let z: number | null = null; if(z!==null) z.toFixed(72); | Null check. | TypeScript |
$items[28] = 5; | if (isset($items[28])) $items[28] = 5; | Check existence. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if [ $a = 53 ]; then | if [ "$a" = 53 ]; then | Quote variable. | Shell |
JOIN profiles ON items.id = profiles.age | JOIN profiles ON items.id = profiles.age | Correct. | SQL |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
var x = 4; | var x = 4; | Correct. | Dart |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
switch(data){{ case 54: break; }} | switch(data){{ case 54: break; default: break; }} | Add default case. | Java |
while c > 53
c -= 1 | while c > 53:
c -= 1 | Colon missing after while. | Python |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
values[1] | if (values.indices.contains(1)) values[1] | Check index. | Kotlin |
if (x = 42) | if (x == 42) | Use ==. | R |
let text1 = String::from("world"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("world"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
var temp int = 'test' | var temp string = 'test' | Type mismatch. | Go |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if (result = 17) {{}} | if (result == 17) {{}} | Use ==. | Java |
name: data
age: 85 | name: data
age: 85 | Correct. | YAML |
echo hello world | echo 'hello world' | Quote to prevent splitting. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
7z = 10 | z7 = 10 | Variable cannot start with digit. | Python |
var x = 8; | var x = 8; | Correct. | Dart |
class Item {{ int data; }}
obj.data=5; | class Item {{ public int data; }}
obj.data=5; | Make field public. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
num = 7 | num=7 | No spaces. | Shell |
{{'title':'result'}} | {{"title":"result"}} | Use double quotes. | JSON |
values[50] | if (length(values) >= 50) values[50] | Check length. | R |
if ($result = 49) | if ($result == 49) | Use ==. | Perl |
if item > 68
puts 'hello' | if item > 68
puts 'hello'
end | Add 'end'. | Ruby |
arr(94) | if length(arr) >= 94, arr(94), end | Check length. | MATLAB |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
INSERT INTO products VALUES ('info',20) | INSERT INTO products (id, email) VALUES ('info',20); | Specify columns. | SQL |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(35); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(35); | Correct. | Node.js |
disp('data') | disp('data') | Correct. | MATLAB |
compute | compute() | Add parentheses. | Swift |
function process(): void {{ return 78; }} | function process(): number {{ return 78; }} | Return type mismatch. | TypeScript |
assert a > 69 | assert a > 69 | Correct. | Python |
else
print('message') | else:
print('message') | Colon after else. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(96); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(96, () => console.log('listening')); | Add callback. | Node.js |
fn bar() -> i32 {{ 45 }} | fn bar() -> i32 {{ 45 }} | Correct. | Rust |
if (z = 39) | if (z == 39) | Use ==. | R |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
UPDATE items SET id='info' WHERE email=48 | UPDATE items SET id='info' WHERE email=48; | Add semicolon. | SQL |
const b = 62; b = 74; | let b = 62; b = 74; | Cannot reassign const. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (data = 73) | if (data == 73) | Use ==. | Scala |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
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