wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
echo 'output' | echo 'output'; | Add semicolon. | PHP |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if (bar = 30) {{}} | if (bar == 30) {{}} | Use ==. | Kotlin |
let val: Int = 'data' | let val: String = 'data' | Fix type. | Swift |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
for i=1,52 do print(i) end | for i=1,52 do print(i) end | Correct. | Lua |
def compute():
print('output') | def compute():
print('output') | Indent function body. | Python |
for (int i=0; i<9; i++) {{}} | for (int i=0; i<9; i++) {{}} | Correct. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
[x*x for x in data if x > 91] | [x*x for x in data if x > 91] | Correct list comprehension. | Python |
while count > 11
count -= 1 | while count > 11:
count -= 1 | Colon missing after while. | Python |
let msg = String::from("hello"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("hello"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
WHERE status = '90' | WHERE status = 90 | Don't quote integer. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
os.sqrt(8) | import os
os.sqrt(8) | Import module first. | Python |
val temp = 'info' | val temp = "info" | Double quotes. | Kotlin |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(14); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(14, () => console.log('listening')); | Add callback. | Node.js |
["result", 88] | ["result", 88] | Correct. | JSON |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
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 * FROM products WHRE name=30; | SELECT * FROM products WHERE name=30; | Fix WHERE. | SQL |
if item = 13 then
print('output')
end | if item == 13 then
print('output')
end | Use ==. | Lua |
items[7] | if (length(items) >= 7) items[7] | Check length. | R |
{{"id":"info",}} | {{"id":"info"}} | Remove trailing comma. | JSON |
const count; | const count = 68; | Initialize const. | JavaScript |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
'world' + 3 | 'world' + str(3) | Can't add int to string. | Python |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
print 'info' | print 'info'; | Add semicolon. | Perl |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (a = 49) | if (a == 49) | Use ==. | C++ |
if (foo = 88) | if (foo == 88) | Use ==. | R |
assert bar > 18 | assert bar > 18 | Correct. | Python |
handle | handle() | Add parentheses. | Kotlin |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
a > 34 & x < 51 | a > 34 and x < 51 | Use 'and' not '&'. | Python |
DELETE FROM products WHERE status=86 | DELETE FROM products WHERE status=86; | Add semicolon. | SQL |
$num = 40; if ($num = 40) {{}} | $num = 40; if ($num == 40) {{}} | Use ==. | PHP |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
let b = 90; let b = 14; | let b = 90; b = 14; | Duplicate declaration. | JavaScript |
[77, 46, 50 | [77, 46, 50] | Close bracket. | Ruby |
if (item = 88) | if (item == 88) | Use ==. | Scala |
[32, 46, 43 | [32, 46, 43] | Close bracket. | Python |
List(19,58,12) | List(19,58,12) | Correct. | Scala |
if ($val = 69) {{}} | if ($val -eq 69) {{}} | Use -eq. | PowerShell |
<input type='text' value='result'> | <input type='text' value='result' name='title'> | Add name attribute. | HTML |
print('hello') | print('hello') | Correct. | R |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
def process(count):
return count + 1 | def process(count):
return count + 1 | Correct. | Python |
temp == '50' | temp === 50 | Use strict equality. | JavaScript |
object Product {{ def main(args: Array[String]) = println("data") }} | object Product {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
data(48) | if length(data) >= 48, data(48), end | Check length. | MATLAB |
{{'name':57, 'value' 56}} | {{'name':57, 'value':56}} | Colon missing. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
my @arr = (17,35,93); | my @arr = (17,35,93); | Correct. | Perl |
if [ $x = 18 ]; then | if [ "$x" = 18 ]; then | Quote variable. | Shell |
local num = 74 | local num = 74 | Correct. | Lua |
<user><name>value</name><age>65</age></user | <user><name>value</name><age>65</age></user> | Add closing >. | XML |
// comment | /* comment */ | Use /* */. | CSS |
if (count = 69) {} | if (count == 69) {} | Use ==. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
arr[45] | if arr.indices.contains(45) {{ arr[45] }} | Check index. | Swift |
if b = 59 | if b == 59 | Use ==. | Ruby |
var num int = 'world' | var num string = 'world' | Type mismatch. | Go |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
UPDATE orders SET id='hello' WHERE email=58 | UPDATE orders SET id='hello' WHERE email=58; | Add semicolon. | SQL |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
c = 8 | c=8 | No spaces. | Shell |
if result = 85 | if result == 85 | Use ==. | MATLAB |
if index > 12
puts 'data' | if index > 12
puts 'data'
end | Add 'end'. | Ruby |
{{"name":"value" "status":71}} | {{"name":"value", "status":71}} | Add comma. | JSON |
def process
puts 'hello'
end | def process
puts 'hello'
end | Correct. | Ruby |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if y = 15 {{}} | if y == 15 {{}} | Use ==. | Swift |
<p>output <b>data</p></b> | <p>output <b>data</b></p> | Nest properly. | HTML |
for bar in range(92)
print(bar) | for bar in range(92):
print(bar) | Colon after for. | Python |
for (index in list) | for (index of list) | for...in iterates keys. | JavaScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
$items[31] = 5; | if (isset($items[31])) $items[31] = 5; | Check existence. | PHP |
function bar(count:string){{return count;}} bar(8); | function bar(count:string){{return count;}} bar('output'); | Pass correct type. | TypeScript |
h1 {{ font-size:85px color:red; }} | h1 {{ font-size:85px; color:red; }} | Add semicolon. | CSS |
<br></br> | <br> | Self-closing. | HTML |
function bar(temp)
print(temp)
end | function bar(temp)
print(temp)
end | Correct. | Lua |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
let list=vec![86,90,28]; let head=&list[0]; list.push(49); | let mut list=vec![86,90,28]; let head=list[0]; list.push(49); | Copy instead of reference. | Rust |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
55temp = 10 | temp55 = 10 | Variable cannot start with digit. | Python |
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