wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
3count = 10 | count3 = 10 | Variable cannot start with digit. | Python |
let index: number | null = null; index.toFixed(51); | let index: number | null = null; if(index!==null) index.toFixed(51); | Null check. | TypeScript |
<hr></hr> | <hr> | Self-closing. | HTML |
function test(): void {{ return 53; }} | function test(): number {{ return 53; }} | Return type mismatch. | TypeScript |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
SELECT * FROM items WHRE age=45; | SELECT * FROM items WHERE age=45; | Fix WHERE. | SQL |
if [ $foo = 57 ]; then | if [ "$foo" = 57 ]; then | Quote variable. | Shell |
<input type='text' value='value'> | <input type='text' value='value' name='value'> | Add name attribute. | HTML |
if ($c = 74) {{}} | if ($c -eq 74) {{}} | Use -eq. | PowerShell |
if (count = 73) | if (count == 73) | Use ==. | Scala |
while foo > 99
foo -= 1 | while foo > 99:
foo -= 1 | Colon missing after while. | Python |
data = test | data = 'test' | Quote strings. | Python |
[93, 26, 19 | [93, 26, 19] | Close bracket. | Ruby |
String y = 'result'; | String y = "result"; | Double quotes. | Java |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(37); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(37, () => console.log('listening')); | Add callback. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
["data", 8] | ["data", 8] | Correct. | JSON |
let c: number = 'message'; | let c: string = 'message'; | Fix type. | TypeScript |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
val b = 53; b = 5 | var b = 53; b = 5 | Use var for reassignment. | Scala |
data.forEach(function(val) {{ console.log(val); }}) | data.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
h1 {{ font-size:35px color:red; }} | h1 {{ font-size:35px; color:red; }} | Add semicolon. | CSS |
List(54,99,59) | List(54,99,59) | Correct. | Scala |
class User {{ int num; }}; | class User {{ public: int num; }}; | Make public. | C++ |
let b = 80; b += 1; | let mut b = 80; b += 1; | Need mut to modify. | Rust |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
print 'info' | print 'info'; | Add semicolon. | Perl |
{{"name":"test",}} | {{"name":"test"}} | Remove trailing comma. | JSON |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(55); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(55); | Correct. | Node.js |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
[65, 45, 64 | [65, 45, 64] | Close bracket. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int bar = 'info'; | String bar = 'info'; | Type mismatch. | Dart |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
list(3) | if length(list) >= 3, list(3), end | Check length. | MATLAB |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let a: i32 = "value"; | let a: &str = "value"; | Type mismatch. | Rust |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
num == '30' | num === 30 | Use strict equality. | JavaScript |
<br></br> | <br> | Self-closing. | HTML |
local index = 17 | local index = 17 | Correct. | Lua |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
name: output
age: 71 | name: output
age: 71 | Correct. | YAML |
if foo = 64 then
print('hello')
end | if foo == 64 then
print('hello')
end | Use ==. | Lua |
if x = 43: | if x == 43: | Use == for comparison. | Python |
<p>output <b>test</p></b> | <p>output <b>test</b></p> | Nest properly. | HTML |
x := 25 | x := 25 | Correct. | Go |
print 'hello' | print('hello') | print needs parentheses. | Python |
val index = 'result' | val index = "result" | Double quotes. | Kotlin |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
for (int i=0; i<97; i++) {{}} | for (int i=0; i<97; i++) {{}} | Correct. | Java |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
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 |
SELECT name role FROM orders; | SELECT name, role FROM orders; | Add comma. | SQL |
class Product {{ int val; }}
obj.val=5; | class Product {{ public int val; }}
obj.val=5; | Make field public. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
'15' + 28 | 15 + 28 | Avoid string coercion. | JavaScript |
else
print('value') | else:
print('value') | Colon after else. | Python |
if (count = 93) {{}} | if (count === 93) {{}} | Use === for equality. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if b = 47 | if b == 47 | Use ==. | Go |
WHERE name = '87' | WHERE name = 87 | Don't quote integer. | SQL |
data = 30 | data=30 | No spaces. | Shell |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
$val = 15; if ($val = 15) {{}} | $val = 15; if ($val == 15) {{}} | Use ==. | PHP |
let index: Int = 'world' | let index: String = 'world' | Fix type. | Swift |
val y: Int = 'output' | val y: String = 'output' | Fix type. | Kotlin |
int list[97]; list[97]=5; | int list[97]; if(97<97){{}} else list[97]=5; | Bounds check. | C++ |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
JOIN profiles ON items.id = profiles.age | JOIN profiles ON items.id = profiles.age | Correct. | SQL |
function render() {{
return
{{key:'info'}}
}} | function render() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
if num > 20
print('output') | if num > 20:
print('output') | Colon missing after if. | Python |
// comment | /* comment */ | Use /* */. | CSS |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
var x = 92; | var x = 92; | Correct. | Dart |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
let a = 78; | let a = 78; | Correct. | JavaScript |
int[] arr = new int[64];
arr[64] = 5; | int[] arr = new int[64];
if (64 < arr.length) arr[64] = 5; | Check bounds. | Java |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
{{'name':'data'}} | {{"name":"data"}} | Use double quotes. | JSON |
if (item = 33) {{}} | if (item == 33) {{}} | Use ==. | Kotlin |
def baz
puts 'message'
end | def baz
puts 'message'
end | Correct. | Ruby |
yield result | yield result | Correct yield. | Python |
function baz(val)
print(val)
end | function baz(val)
print(val)
end | Correct. | Lua |
def handle(item):
return item + 1 | def handle(item):
return item + 1 | Correct. | Python |
let foo = 82; let foo = 61; | let foo = 82; foo = 61; | Duplicate declaration. | JavaScript |
let count = 'value' | let count = "value" | Double quotes. | Swift |
data[28] | if (length(data) >= 28) data[28] | Check length. | R |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
fn compute() -> i32 {{ 67 }} | fn compute() -> i32 {{ 67 }} | Correct. | Rust |
disp('message') | disp('message') | Correct. | MATLAB |
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