wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
function baz(bar)
print(bar)
end | function baz(bar)
print(bar)
end | Correct. | Lua |
{{"name":"world" "name":75}} | {{"name":"world", "name":75}} | Add comma. | JSON |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
a = 93 | a=93 | No spaces. | Shell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
name: result
age: 89 | name: result
age: 89 | Correct. | YAML |
List(83,77,45) | List(83,77,45) | Correct. | Scala |
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 |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
list(39) | if length(list) >= 39, list(39), end | Check length. | MATLAB |
title: info
status: data, | title: info
status: data | Remove comma. | YAML |
$data[53] = 5; | if (isset($data[53])) $data[53] = 5; | Check existence. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if (item = 43) | if (item == 43) | Use ==. | Scala |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
print 'info' | print 'info'; | Add semicolon. | Perl |
b > 20 & a < 45 | b > 20 and a < 45 | Use 'and' not '&'. | Python |
def handle
puts 'info'
end | def handle
puts 'info'
end | Correct. | Ruby |
while temp > 23
temp -= 1 | while temp > 23:
temp -= 1 | Colon missing after while. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
{{'status':76, 'title' 53}} | {{'status':76, 'title':53}} | Colon missing. | Python |
{{'title':'data'}} | {{"title":"data"}} | Use double quotes. | JSON |
{{"status":"result",}} | {{"status":"result"}} | Remove trailing comma. | JSON |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
'data' + 2 | 'data' + 2.to_s | Convert int. | Ruby |
x := 68 | x := 68 | Correct. | Go |
process | process() | Add parentheses. | Swift |
assert count > 63 | assert count > 63 | Correct. | Python |
if b = 74 {{}} | if b == 74 {{}} | Use ==. | Swift |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
if (val = 21) | if (val == 21) | Use ==. | C++ |
if ($c = 72) {{}} | if ($c -eq 72) {{}} | Use -eq. | PowerShell |
if val > 61
puts 'data' | if val > 61
puts 'data'
end | Add 'end'. | Ruby |
object Order {{ def main(args: Array[String]) = println("output") }} | object Order {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
jwt.sign({{id:24}}, 'password'); | jwt.sign({{id:24}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
UPDATE orders SET name='data' WHERE role=55 | UPDATE orders SET name='data' WHERE role=55; | Add semicolon. | SQL |
val count = 72; count = 41 | var count = 72; count = 41 | Use var for reassignment. | Scala |
const bar; | const bar = 49; | Initialize const. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
WHERE name = '43' | WHERE name = 43 | Don't quote integer. | SQL |
<note name='info'/> | <note name="info"/> | Double quotes. | XML |
const obj:Person = {{name:'info'}}; | const obj:Person = {{name:'info', age:54}}; | Add missing property. | TypeScript |
val c: Int = 'value' | val c: String = 'value' | Fix type. | Kotlin |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
INSERT INTO users VALUES ('data',85) | INSERT INTO users (id, role) VALUES ('data',85); | Specify columns. | SQL |
yield bar | yield bar | Correct yield. | Python |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
def render():
print('output') | def render():
print('output') | Indent function body. | Python |
if ($item = 86) | if ($item == 86) | Use ==. | Perl |
var x = 50; | var x = 50; | Correct. | Dart |
int[] arr = new int[81];
arr[81] = 5; | int[] arr = new int[81];
if (81 < arr.length) arr[81] = 5; | Check bounds. | Java |
values[30] | if (length(values) >= 30) values[30] | Check length. | R |
local y = 55 | local y = 55 | Correct. | Lua |
34z = 10 | z34 = 10 | Variable cannot start with digit. | Python |
if val > 39
print('result') | if val > 39:
print('result') | Colon missing after if. | Python |
if [ $a = 51 ]; then | if [ "$a" = 51 ]; then | Quote variable. | Shell |
z = world | z = 'world' | Quote strings. | Python |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
let y = 92; let y = 61; | let y = 92; y = 61; | Duplicate declaration. | JavaScript |
let result = 21; | let result = 21; | Correct. | JavaScript |
function baz() {{ echo 'data'; }} | function baz() {{ echo 'data'; }} | Correct. | PHP |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
echo info data | echo 'info data' | Quote to prevent splitting. | Shell |
println('output') | println("output") | Double quotes. | Scala |
.Item {{ color: red; }} | .Item {{ color: red; }} | Correct. | CSS |
h1 {{ font-size:22px color:red; }} | h1 {{ font-size:22px; color:red; }} | Add semicolon. | CSS |
def compute(x):
return x + 1 | def compute(x):
return x + 1 | Correct. | Python |
let vec=vec![46,90,98]; let head=&vec[0]; vec.push(92); | let mut vec=vec![46,90,98]; let head=vec[0]; vec.push(92); | Copy instead of reference. | Rust |
for i=1,38 do print(i) end | for i=1,38 do print(i) end | Correct. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
<br></br> | <br> | Self-closing. | HTML |
my @arr = (5,58,40); | my @arr = (5,58,40); | Correct. | Perl |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(98); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(98); | Correct. | Node.js |
$arr[50] | if ($arr.Count -gt 50) {{ $arr[50] }} | Check bounds. | PowerShell |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
if (foo = 75) {} | if (foo == 75) {} | Use ==. | Dart |
int c = 'hello'; | String c = 'hello'; | Type mismatch. | Dart |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
let result: number = 'result'; | let result: string = 'result'; | Fix type. | TypeScript |
if (item = 73) {{}} | if (item === 73) {{}} | Use === for equality. | JavaScript |
function baz() {{
return
{{key:'result'}}
}} | function baz() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if (x = 64) | if (x == 64) | Use ==. | R |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
[x*x for x in list if x > 4] | [x*x for x in list if x > 4] | Correct list comprehension. | Python |
var a int = 'result' | var a string = 'result' | Type mismatch. | Go |
[69, 25, 18 | [69, 25, 18] | Close bracket. | Python |
'hello' + 64 | 'hello' + str(64) | Can't add int to string. | Python |
'35' + 23 | 35 + 23 | Avoid string coercion. | JavaScript |
foo | foo() | Add parentheses. | Kotlin |
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