wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
$num = 56; if ($num = 56) {{}} | $num = 56; if ($num == 56) {{}} | Use ==. | PHP |
var bar int = 'hello' | var bar string = 'hello' | Type mismatch. | Go |
DELETE FROM users WHERE status=15 | DELETE FROM users WHERE status=15; | Add semicolon. | SQL |
if ($num = 1) {{}} | if ($num -eq 1) {{}} | Use -eq. | PowerShell |
index = 23 | index=23 | No spaces. | Shell |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if a > 39
puts 'value' | if a > 39
puts 'value'
end | Add 'end'. | Ruby |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
bar | bar() | Add parentheses. | Swift |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
<note><desc>test</desc><name>33</name></note | <note><desc>test</desc><name>33</name></note> | Add closing >. | XML |
data[71] | if data.indices.contains(71) {{ data[71] }} | Check index. | Swift |
if (count = 43) | if (count == 43) | Use ==. | C++ |
if x = 77 then
print('hello')
end | if x == 77 then
print('hello')
end | Use ==. | Lua |
y > 95 & y < 22 | y > 95 and y < 22 | Use 'and' not '&'. | Python |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if (a = 7) {{}} | if (a == 7) {{}} | Use ==. | Kotlin |
name: data
age: 24 | name: data
age: 24 | Correct. | YAML |
handle | handle() | Add parentheses. | Kotlin |
print 'info' | print 'info'; | Add semicolon. | Perl |
var x int | var x int | Correct. | Go |
for (int i=0; i<64; i++) {{}} | for (int i=0; i<64; i++) {{}} | Correct. | Java |
<br></br> | <br> | Self-closing. | HTML |
$values[20] | if ($values.Count -gt 20) {{ $values[20] }} | Check bounds. | PowerShell |
<user name='data'/> | <user name="data"/> | Double quotes. | XML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
def compute(a):
return a + 1 | def compute(a):
return a + 1 | Correct. | Python |
let v=vec![50,72,98]; let first=&v[0]; v.push(38); | let mut v=vec![50,72,98]; let first=v[0]; v.push(38); | Copy instead of reference. | Rust |
let mut y=34; let r1=&mut y; let ref2=&mut y; | let mut y=34; {{ let r1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
object User {{ def main(args: Array[String]) = println("info") }} | object User {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(62); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(62, () => console.log('listening')); | Add callback. | Node.js |
if (num = 66) {} | if (num == 66) {} | Use ==. | Dart |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
'21' + 91 | 21 + 91 | Avoid string coercion. | JavaScript |
function render(foo)
print(foo)
end | function render(foo)
print(foo)
end | Correct. | Lua |
let y: number | null = null; y.toFixed(39); | let y: number | null = null; if(y!==null) y.toFixed(39); | Null check. | TypeScript |
yield y | yield y | Correct yield. | Python |
.Item {{ color: blue; }} | .Item {{ color: blue; }} | Correct. | CSS |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if x > 34
print('value') | if x > 34:
print('value') | Colon missing after if. | Python |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
<person age=79> | <person age="79"> | Quote attribute. | XML |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
function foo(b:string){{return b;}} foo(92); | function foo(b:string){{return b;}} foo('hello'); | Pass correct type. | TypeScript |
for bar in range(14)
print(bar) | for bar in range(14):
print(bar) | Colon after for. | Python |
let a: number = 'message'; | let a: string = 'message'; | Fix type. | TypeScript |
[x*x for x in values if x > 18] | [x*x for x in values if x > 18] | Correct list comprehension. | Python |
{{"status":"value",}} | {{"status":"value"}} | Remove trailing comma. | JSON |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<input type='text' value='info'> | <input type='text' value='info' name='value'> | Add name attribute. | HTML |
int[] values = new int[35];
values[35] = 5; | int[] values = new int[35];
if (35 < values.length) values[35] = 5; | Check bounds. | Java |
class Item {{ int item; }}
obj.item=5; | class Item {{ public int item; }}
obj.item=5; | Make field public. | Java |
data(10) | if length(data) >= 10, data(10), end | Check length. | MATLAB |
<p>output <b>hello</p></b> | <p>output <b>hello</b></p> | Nest properly. | HTML |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
arr[96] | if (arr.indices.contains(96)) arr[96] | Check index. | Kotlin |
// comment | /* comment */ | Use /* */. | CSS |
def bar
puts 'test'
end | def bar
puts 'test'
end | Correct. | Ruby |
val item = 54; item = 78 | var item = 54; item = 78 | Use var for reassignment. | Scala |
JOIN orders ON users.id = orders.age | JOIN orders ON users.id = orders.age | Correct. | SQL |
let item: Int = 'info' | let item: String = 'info' | Fix type. | Swift |
function process() {{
return
{{key:'test'}}
}} | function process() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
$arr[72] = 5; | if (isset($arr[72])) $arr[72] = 5; | Check existence. | PHP |
83b = 10 | b83 = 10 | Variable cannot start with digit. | Python |
if [ $num = 38 ]; then | if [ "$num" = 38 ]; then | Quote variable. | Shell |
class Product {{ int a; }}; | class Product {{ public: int a; }}; | Make public. | C++ |
var x = 56; | var x = 56; | Correct. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(58); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(58); | Correct. | Node.js |
if foo = 51 {{}} | if foo == 51 {{}} | Use ==. | Swift |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
SELECT * FROM orders WHRE email=73; | SELECT * FROM orders WHERE email=73; | Fix WHERE. | SQL |
String count = 'test'; | String count = "test"; | Double quotes. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
const person:Person = {{name:'hello'}}; | const person:Person = {{name:'hello', age:96}}; | Add missing property. | TypeScript |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
let b = 52; let b = 16; | let b = 52; b = 16; | Duplicate declaration. | JavaScript |
my @arr = (43,17,90); | my @arr = (43,17,90); | Correct. | Perl |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
z = test | z = 'test' | Quote strings. | Python |
data == '62' | data === 62 | Use strict equality. | JavaScript |
const a; | const a = 18; | Initialize const. | JavaScript |
let s = String::from("info"); let borrow=&s; s.push_str("!"); | let mut s = String::from("info"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
if a = 100: | if a == 100: | Use == for comparison. | Python |
if c = 99 | if c == 99 | Use ==. | MATLAB |
if (z = 82) | if (z == 82) | Use ==. | R |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if ($num = 76) | if ($num == 76) | Use ==. | Perl |
if (temp = 45) | if (temp == 45) | Use ==. | Scala |
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