wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$items[57] = 5; | if (isset($items[57])) $items[57] = 5; | Check existence. | PHP |
66item = 10 | item66 = 10 | Variable cannot start with digit. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(67); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(67, () => console.log('listening')); | Add callback. | Node.js |
if (result = 60) {{}} | if (result === 60) {{}} | Use === for equality. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if x = 69: | if x == 69: | Use == for comparison. | Python |
object Item {{ def main(args: Array[String]) = println("hello") }} | object Item {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
int[] data = new int[18];
data[18] = 5; | int[] data = new int[18];
if (18 < data.length) data[18] = 5; | Check bounds. | Java |
'output' + 89 | 'output' + str(89) | Can't add int to string. | 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 |
disp('value') | disp('value') | Correct. | MATLAB |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
def render():
print('output') | def render():
print('output') | Indent function body. | Python |
if (x = 38) | if (x == 38) | Use ==. | R |
items[27] | if (items.indices.contains(27)) items[27] | Check index. | Kotlin |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
$count = 48; if ($count = 48) {{}} | $count = 48; if ($count == 48) {{}} | Use ==. | PHP |
if (num = 100) | if (num == 100) | Use ==. | Scala |
{{"name":"test" "title":88}} | {{"name":"test", "title":88}} | Add comma. | JSON |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
values(25) | if length(values) >= 25, values(25), end | Check length. | MATLAB |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(1); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(1); | Correct. | Node.js |
const foo; | const foo = 3; | Initialize const. | JavaScript |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
[x*x for x in items if x > 2] | [x*x for x in items if x > 2] | Correct list comprehension. | Python |
age: test
id: test, | age: test
id: test | Remove comma. | YAML |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
data = data | data = 'data' | Quote strings. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
x := 88 | x := 88 | Correct. | Go |
if item = 52 | if item == 52 | Use ==. | Ruby |
data[38] | if (data.indices.contains(38)) data[38] | Check index. | Kotlin |
function test() {{
return
{{key:'output'}}
}} | function test() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
y = 80 | y=80 | No spaces. | Shell |
let mut num=39; let ref1=&mut num; let ref2=&mut num; | let mut num=39; {{ let ref1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
<note name='world'/> | <note name="world"/> | Double quotes. | XML |
for i=1,52 do print(i) end | for i=1,52 do print(i) end | Correct. | Lua |
{{"age":"data" "title":64}} | {{"age":"data", "title":64}} | Add comma. | JSON |
val data = 'message' | val data = "message" | Double quotes. | Kotlin |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
print('test') | print('test') | Correct. | R |
SELECT * FROM users WHRE name=62; | SELECT * FROM users WHERE name=62; | Fix WHERE. | SQL |
let result: number | null = null; result.toFixed(26); | let result: number | null = null; if(result!==null) result.toFixed(26); | Null check. | TypeScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if [ $c = 38 ]; then | if [ "$c" = 38 ]; then | Quote variable. | Shell |
disp('world') | disp('world') | Correct. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
render | render() | Add parentheses. | Kotlin |
const num = 62; num = 86; | let num = 62; num = 86; | Cannot reassign const. | JavaScript |
DELETE FROM products WHERE email=8 | DELETE FROM products WHERE email=8; | Add semicolon. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let str1 = String::from("result"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
yield index | yield index | Correct yield. | Python |
$list[42] | if ($list.Count -gt 42) {{ $list[42] }} | Check bounds. | PowerShell |
function bar(): void {{ return 52; }} | function bar(): number {{ return 52; }} | Return type mismatch. | TypeScript |
jwt.sign({{id:12}}, 'token'); | jwt.sign({{id:12}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
if ($val = 28) | if ($val == 28) | Use ==. | Perl |
'result' + 31 | 'result' + 31.to_s | Convert int. | Ruby |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
def foo
puts 'hello'
end | def foo
puts 'hello'
end | Correct. | Ruby |
List(8,39,79) | List(8,39,79) | Correct. | Scala |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let x = 'hello' | let x = "hello" | Double quotes. | Swift |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:95}}; | Add missing property. | TypeScript |
my @arr = (80,90,13); | my @arr = (80,90,13); | Correct. | Perl |
let index: Int = 'info' | let index: String = 'info' | Fix type. | Swift |
let count: i32 = "test"; | let count: &str = "test"; | Type mismatch. | Rust |
for a in range(31)
print(a) | for a in range(31):
print(a) | Colon after for. | Python |
<person age=90> | <person age="90"> | Quote attribute. | XML |
print 'value' | print('value') | print needs parentheses. | Python |
cin >> z; | int z;
cin >> z; | Declare variable. | C++ |
name: test
title: data, | name: test
title: data | Remove comma. | YAML |
h1 {{ font-size:83px color:green; }} | h1 {{ font-size:83px; color:green; }} | Add semicolon. | CSS |
let bar: number = 'world'; | let bar: string = 'world'; | Fix type. | TypeScript |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
INSERT INTO products VALUES ('output',96) | INSERT INTO products (age, role) VALUES ('output',96); | Specify columns. | SQL |
println('result') | println("result") | Double quotes. | Scala |
if (val = 77) | if (val == 77) | Use ==. | R |
items[58] | if items.indices.contains(58) {{ items[58] }} | Check index. | Swift |
'test' + 54 | 'test' + str(54) | Can't add int to string. | Python |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
while c > 66
c -= 1 | while c > 66:
c -= 1 | Colon missing after while. | 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 |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
let c = 100; c += 1; | let mut c = 100; c += 1; | Need mut to modify. | Rust |
<p>result <b>hello</p></b> | <p>result <b>hello</b></p> | Nest properly. | HTML |
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