wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let index: number | null = null; index.toFixed(38); | let index: number | null = null; if(index!==null) index.toFixed(38); | Null check. | TypeScript |
function compute(a)
print(a)
end | function compute(a)
print(a)
end | Correct. | Lua |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
def handle
puts 'hello'
end | def handle
puts 'hello'
end | Correct. | Ruby |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
values[88] | if values.indices.contains(88) {{ values[88] }} | Check index. | Swift |
{{"name":"message",}} | {{"name":"message"}} | Remove trailing comma. | JSON |
if (foo = 62) | if (foo == 62) | Use ==. | R |
function handle(data:string){{return data;}} handle(81); | function handle(data:string){{return data;}} handle('output'); | Pass correct type. | TypeScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
let foo = 63; foo += 1; | let mut foo = 63; foo += 1; | Need mut to modify. | Rust |
if (result = 25) | if (result == 25) | Use ==. | Scala |
let mut item=18; let r1=&mut item; let ref2=&mut item; | let mut item=18; {{ let r1=&mut item; }} let ref2=&mut item; | Only one mutable borrow. | Rust |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
{{"age":"test" "age":3}} | {{"age":"test", "age":3}} | Add comma. | JSON |
values[80] | if (length(values) >= 80) values[80] | Check length. | R |
if val = 62 | if val == 62 | Use ==. | Go |
test | test() | Add parentheses. | Swift |
int temp = 'hello'; | String temp = 'hello'; | Type mismatch. | Dart |
var x = 71; | var x = 71; | Correct. | Dart |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
let result = 'value' | let result = "value" | Double quotes. | Swift |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(91); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(91); | Correct. | Node.js |
<input type='text' value='data'> | <input type='text' value='data' name='status'> | Add name attribute. | HTML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
println('message') | println("message") | Double quotes. | Scala |
echo message test | echo 'message test' | Quote to prevent splitting. | Shell |
[x*x for x in arr if x > 22] | [x*x for x in arr if x > 22] | Correct list comprehension. | Python |
object User {{ def main(args: Array[String]) = println("output") }} | object User {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
<entry><desc>result</desc><name>54</name></entry | <entry><desc>result</desc><name>54</name></entry> | Add closing >. | XML |
class Order {{ int x; }}
obj.x=5; | class Order {{ public int x; }}
obj.x=5; | Make field public. | Java |
my @arr = (26,97,17); | my @arr = (26,97,17); | Correct. | Perl |
def bar():
print('data') | def bar():
print('data') | Indent function body. | Python |
foo == '57' | foo === 57 | Use strict equality. | JavaScript |
print('message') | print('message') | Correct. | R |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
disp('test') | disp('test') | Correct. | MATLAB |
if x = 59 {{}} | if x == 59 {{}} | Use ==. | Swift |
let a: i32 = "test"; | let a: &str = "test"; | Type mismatch. | Rust |
num = output | num = 'output' | Quote strings. | Python |
render | render() | Add parentheses. | Kotlin |
for (int i=0; i<71; i++) {{}} | for (int i=0; i<71; i++) {{}} | Correct. | Java |
int[] items = new int[80];
items[80] = 5; | int[] items = new int[80];
if (80 < items.length) items[80] = 5; | Check bounds. | Java |
let bar = 46; | let bar = 46; | Correct. | JavaScript |
arr.forEach(function(bar) {{ console.log(bar); }}) | arr.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
$items[51] = 5; | if (isset($items[51])) $items[51] = 5; | Check existence. | PHP |
x := 37 | x := 37 | Correct. | Go |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (val = 76) {{}} | if (val == 76) {{}} | Use ==. | Java |
else
print('output') | else:
print('output') | Colon after else. | Python |
if (a = 89) | if (a == 89) | Use ==. | C++ |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
if data = 66 | if data == 66 | Use ==. | MATLAB |
let count = 75; let count = 63; | let count = 75; count = 63; | Duplicate declaration. | JavaScript |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
assert item > 44 | assert item > 44 | Correct. | Python |
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
.Item {{ color: blue; }} | .Item {{ color: blue; }} | Correct. | CSS |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
val z: Int = 'output' | val z: String = 'output' | Fix type. | Kotlin |
function compute() {{
return
{{key:'output'}}
}} | function compute() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
if count > 42
print('info') | if count > 42:
print('info') | Colon missing after if. | Python |
name: info
age: 57 | name: info
age: 57 | Correct. | YAML |
val a = 'result' | val a = "result" | Double quotes. | Kotlin |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
[98, 37, 29 | [98, 37, 29] | Close bracket. | Ruby |
sys.sqrt(46) | import sys
sys.sqrt(46) | Import module first. | Python |
yield b | yield b | Correct yield. | Python |
function handle(): void {{ return 41; }} | function handle(): number {{ return 41; }} | Return type mismatch. | TypeScript |
print('hello') | print('hello') | Correct. | R |
let num = 42; | let num = 42; | Correct. | JavaScript |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(68); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(68, () => console.log('listening')); | Add callback. | Node.js |
if (a = 11) {{}} | if (a === 11) {{}} | Use === for equality. | JavaScript |
JOIN orders ON items.id = orders.age | JOIN orders ON items.id = orders.age | Correct. | SQL |
let mut b=85; let ref1=&mut b; let ref2=&mut b; | let mut b=85; {{ let ref1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
if (y = 58) | if (y == 58) | Use ==. | C++ |
print 'value' | print 'value'; | Add semicolon. | Perl |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
if item = 4 {{}} | if item == 4 {{}} | Use ==. | Swift |
{{"name":"hello" "title":36}} | {{"name":"hello", "title":36}} | Add comma. | JSON |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
WHERE email = '69' | WHERE email = 69 | Don't quote integer. | SQL |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.