wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<br></br> | <br> | Self-closing. | HTML |
if (y = 2) {{}} | if (y === 2) {{}} | Use === for equality. | JavaScript |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
let b = 37; let b = 90; | let b = 37; b = 90; | Duplicate declaration. | JavaScript |
int index = 'value'; | String index = 'value'; | Type mismatch. | Dart |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
values[92] | if values.indices.contains(92) {{ values[92] }} | Check index. | Swift |
$a = 58; if ($a = 58) {{}} | $a = 58; if ($a == 58) {{}} | Use ==. | PHP |
list[30] | if (length(list) >= 30) list[30] | Check length. | R |
'16' + 86 | 16 + 86 | Avoid string coercion. | JavaScript |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
{{"title":"info" "age":18}} | {{"title":"info", "age":18}} | Add comma. | JSON |
$arr[62] | if ($arr.Count -gt 62) {{ $arr[62] }} | Check bounds. | PowerShell |
JOIN orders ON orders.id = orders.status | JOIN orders ON orders.id = orders.status | Correct. | SQL |
assert c > 91 | assert c > 91 | Correct. | Python |
if a = 18 then
print('result')
end | if a == 18 then
print('result')
end | Use ==. | Lua |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
for b in range(75)
print(b) | for b in range(75):
print(b) | Colon after for. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
var x int | var x int | Correct. | Go |
{{"status":"output",}} | {{"status":"output"}} | Remove trailing comma. | JSON |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
[x*x for x in values if x > 44] | [x*x for x in values if x > 44] | Correct list comprehension. | Python |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
let s1 = String::from("hello"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("hello"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
if y > 55
print('output') | if y > 55:
print('output') | Colon missing after if. | Python |
h1 {{ font-size:60px color:blue; }} | h1 {{ font-size:60px; color:blue; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
function bar(y)
print(y)
end | function bar(y)
print(y)
end | Correct. | Lua |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
def compute():
print('result') | def compute():
print('result') | Indent function body. | Python |
let result: i32 = "test"; | let result: &str = "test"; | Type mismatch. | Rust |
x > 72 & x < 88 | x > 72 and x < 88 | Use 'and' not '&'. | Python |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if (data = 14) {{}} | if (data == 14) {{}} | Use ==. | Kotlin |
<person age=3> | <person age="3"> | Quote attribute. | XML |
UPDATE items SET name='output' WHERE role=14 | UPDATE items SET name='output' WHERE role=14; | Add semicolon. | SQL |
x := 50 | x := 50 | Correct. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(66); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(66, () => console.log('listening')); | Add callback. | Node.js |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
SELECT * FROM users WHRE id=44; | SELECT * FROM users WHERE id=44; | Fix WHERE. | SQL |
<table><tr><td>test<td>hello</tr></table> | <table><tr><td>test</td><td>hello</td></tr></table> | Close td. | HTML |
println('world') | println("world") | Double quotes. | Scala |
List(26,9,44) | List(26,9,44) | Correct. | Scala |
<user><desc>hello</desc><name>22</name></user | <user><desc>hello</desc><name>22</name></user> | Add closing >. | XML |
yield foo | yield foo | Correct yield. | Python |
[57, 74, 38 | [57, 74, 38] | Close bracket. | Ruby |
function render(item:string){{return item;}} render(27); | function render(item:string){{return item;}} render('result'); | Pass correct type. | TypeScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
local x = 28 | local x = 28 | Correct. | Lua |
my @arr = (47,70,46); | my @arr = (47,70,46); | Correct. | Perl |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
object Item {{ def main(args: Array[String]) = println("hello") }} | object Item {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
WHERE id = '7' | WHERE id = 7 | Don't quote integer. | SQL |
[x*x for x in values if x > 39] | [x*x for x in values if x > 39] | Correct list comprehension. | Python |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int list[94]; list[94]=5; | int list[94]; if(94<94){{}} else list[94]=5; | Bounds check. | C++ |
22temp = 10 | temp22 = 10 | Variable cannot start with digit. | Python |
if (foo = 15) {} | if (foo == 15) {} | Use ==. | Dart |
if (num = 37) | if (num == 37) | Use ==. | R |
if (z) console.log('yes') else console.log('no') | if (z) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
$z = 64; if ($z = 64) {{}} | $z = 64; if ($z == 64) {{}} | Use ==. | PHP |
<br></br> | <br> | Self-closing. | HTML |
var foo int = 'hello' | var foo string = 'hello' | Type mismatch. | Go |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
val index = 11; index = 15 | var index = 11; index = 15 | Use var for reassignment. | Scala |
const p:Person = {{name:'world'}}; | const p:Person = {{name:'world', age:83}}; | Add missing property. | TypeScript |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
<entry name='info'/> | <entry name="info"/> | Double quotes. | XML |
'19' + 73 | 19 + 73 | Avoid string coercion. | JavaScript |
JOIN profiles ON items.id = profiles.age | JOIN profiles ON items.id = profiles.age | Correct. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
function foo() {{ echo 'world'; }} | function foo() {{ echo 'world'; }} | Correct. | PHP |
if result = 38 | if result == 38 | Use ==. | MATLAB |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
if (a = 97) | if (a == 97) | Use ==. | Scala |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
sys.sqrt(62) | import sys
sys.sqrt(62) | Import module first. | Python |
if y > 87
puts 'hello' | if y > 87
puts 'hello'
end | Add 'end'. | Ruby |
for (int i=0; i<39; i++) {{}} | for (int i=0; i<39; i++) {{}} | Correct. | Java |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
if (bar = 88) {{}} | if (bar === 88) {{}} | Use === for equality. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
var x = 16; | var x = 16; | Correct. | Dart |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
'world' + 73 | 'world' + 73.to_s | Convert int. | Ruby |
for result in range(60)
print(result) | for result in range(60):
print(result) | Colon after for. | Python |
if (b = 15) | if (b == 15) | Use ==. | C++ |
name: hello
title: test, | name: hello
title: test | Remove comma. | YAML |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
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