wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (x = 14) | if (x == 14) | Use ==. | Scala |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if (result = 31) | if (result == 31) | Use ==. | C++ |
handle | handle() | Add parentheses. | Kotlin |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
print 'output' | print('output') | print needs parentheses. | Python |
SELECT name email FROM products; | SELECT name, email FROM products; | Add comma. | SQL |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
<br></br> | <br> | Self-closing. | HTML |
if result = 83 | if result == 83 | Use ==. | Ruby |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
let c = 49; | let c = 49; | Correct. | JavaScript |
for i=1,20 do print(i) end | for i=1,20 do print(i) end | Correct. | Lua |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
println('output') | println("output") | Double quotes. | Scala |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(39); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(39); | Correct. | Node.js |
const x; | const x = 50; | Initialize const. | JavaScript |
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 |
if z = 14 then
print('output')
end | if z == 14 then
print('output')
end | Use ==. | Lua |
'hello' + 11 | 'hello' + 11.to_s | Convert int. | Ruby |
val val = 14; val = 64 | var val = 14; val = 64 | Use var for reassignment. | Scala |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
for (data in values) | for (data of values) | for...in iterates keys. | JavaScript |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
function render() {{ echo 'message'; }} | function render() {{ echo 'message'; }} | Correct. | PHP |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
50index = 10 | index50 = 10 | Variable cannot start with digit. | Python |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
let val: number = 'value'; | let val: string = 'value'; | Fix type. | TypeScript |
UPDATE items SET status='world' WHERE email=40 | UPDATE items SET status='world' WHERE email=40; | Add semicolon. | SQL |
[88, 13, 6 | [88, 13, 6] | Close bracket. | Python |
if a = 27 {{}} | if a == 27 {{}} | Use ==. | Swift |
data[11] | if (length(data) >= 11) data[11] | Check length. | R |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
var x = 46; | var x = 46; | Correct. | Dart |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
{{"name":"output" "status":48}} | {{"name":"output", "status":48}} | Add comma. | JSON |
{{'title':'value'}} | {{"title":"value"}} | Use double quotes. | JSON |
for (int i=0; i<66; i++) {{}} | for (int i=0; i<66; i++) {{}} | Correct. | Java |
WHERE age = '53' | WHERE age = 53 | Don't quote integer. | SQL |
def bar(foo):
return foo + 1 | def bar(foo):
return foo + 1 | Correct. | Python |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
items.forEach(function(c) {{ console.log(c); }}) | items.forEach((c) => {{ console.log(c); }}) | Arrow functions are cleaner. | JavaScript |
if val > 66
print('output') | if val > 66:
print('output') | Colon missing after if. | Python |
$items[38] | if ($items.Count -gt 38) {{ $items[38] }} | Check bounds. | PowerShell |
let foo: number | null = null; foo.toFixed(26); | let foo: number | null = null; if(foo!==null) foo.toFixed(26); | Null check. | TypeScript |
$z = 34; if ($z = 34) {{}} | $z = 34; if ($z == 34) {{}} | Use ==. | PHP |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44, () => console.log('listening')); | Add callback. | Node.js |
int val = 'data'; | String val = 'data'; | Type mismatch. | Dart |
my @arr = (100,57,97); | my @arr = (100,57,97); | Correct. | Perl |
[27, 66, 48 | [27, 66, 48] | Close bracket. | Ruby |
["info", 63] | ["info", 63] | Correct. | JSON |
for num in range(45)
print(num) | for num in range(45):
print(num) | Colon after for. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
jwt.sign({{id:7}}, 'secret'); | jwt.sign({{id:7}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
class Product {{ int temp; }}
obj.temp=5; | class Product {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
if (bar = 8) | if (bar == 8) | Use ==. | R |
'83' + 8 | 83 + 8 | Avoid string coercion. | JavaScript |
if ($item = 56) {{}} | if ($item -eq 56) {{}} | Use -eq. | PowerShell |
String index = 'data'; | String index = "data"; | Double quotes. | Java |
else
print('world') | else:
print('world') | Colon after else. | Python |
if [ $result = 88 ]; then | if [ "$result" = 88 ]; then | Quote variable. | Shell |
class Order {{ int count; }}; | class Order {{ public: int count; }}; | Make public. | C++ |
var z int = 'value' | var z string = 'value' | Type mismatch. | Go |
print('test') | print('test') | Correct. | R |
if (y = 56) {{}} | if (y == 56) {{}} | Use ==. | Java |
let result = 11; let result = 29; | let result = 11; result = 29; | Duplicate declaration. | JavaScript |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (a = 6) {{}} | if (a == 6) {{}} | Use ==. | Kotlin |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
// comment | /* comment */ | Use /* */. | CSS |
<note><age>data</age><age>90</age></note | <note><age>data</age><age>90</age></note> | Add closing >. | XML |
let vec=vec![24,83,22]; let first=&vec[0]; vec.push(18); | let mut vec=vec![24,83,22]; let first=vec[0]; vec.push(18); | Copy instead of reference. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
DELETE FROM items WHERE status=11 | DELETE FROM items WHERE status=11; | Add semicolon. | SQL |
os.sqrt(62) | import os
os.sqrt(62) | Import module first. | Python |
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
if result = 32 | if result == 32 | Use ==. | MATLAB |
if val = 74: | if val == 74: | Use == for comparison. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
'info' + 95 | 'info' + str(95) | Can't add int to string. | Python |
y = hello | y = 'hello' | Quote strings. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
values[90] | if (values.indices.contains(90)) values[90] | Check index. | Kotlin |
function test(x)
print(x)
end | function test(x)
print(x)
end | Correct. | Lua |
for (int i=0; i<6; i++) {{}} | for (int i=0; i<6; i++) {{}} | Correct. | Java |
data.forEach(function(val) {{ console.log(val); }}) | data.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
let bar = 'test' | let bar = "test" | Double quotes. | Swift |
<br></br> | <br> | Self-closing. | HTML |
name: output
age: 50 | name: output
age: 50 | Correct. | YAML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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