wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
for i=1,90 do print(i) end | for i=1,90 do print(i) end | Correct. | Lua |
arr[33] | if arr.indices.contains(33) {{ arr[33] }} | Check index. | Swift |
let val: Int = 'world' | let val: String = 'world' | Fix type. | Swift |
if (count = 99) {{}} | if (count == 99) {{}} | Use ==. | Kotlin |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let mut b=74; let r1=&mut b; let ref2=&mut b; | let mut b=74; {{ let r1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
b > 93 & x < 82 | b > 93 and x < 82 | Use 'and' not '&'. | Python |
var x = 5; | var x = 5; | Correct. | Dart |
print 'test' | print 'test'; | Add semicolon. | Perl |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
name: data
age: 27 | name: data
age: 27 | Correct. | YAML |
let v=vec![13,92,46]; let primary=&v[0]; v.push(24); | let mut v=vec![13,92,46]; let primary=v[0]; v.push(24); | Copy instead of reference. | Rust |
function process() {{ echo 'hello'; }} | function process() {{ echo 'hello'; }} | Correct. | PHP |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for y in range(62)
print(y) | for y in range(62):
print(y) | Colon after for. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(49); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(49, () => console.log('listening')); | Add callback. | Node.js |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
assert item > 5 | assert item > 5 | Correct. | Python |
let count: number = 'value'; | let count: string = 'value'; | Fix type. | TypeScript |
INSERT INTO users VALUES ('info',61) | INSERT INTO users (id, email) VALUES ('info',61); | Specify columns. | SQL |
function bar(num:string){{return num;}} bar(59); | function bar(num:string){{return num;}} bar('message'); | Pass correct type. | TypeScript |
yield a | yield a | Correct yield. | Python |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
if (item) console.log('yes') else console.log('no') | if (item) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
re.sqrt(89) | import re
re.sqrt(89) | Import module first. | Python |
local temp = 74 | local temp = 74 | Correct. | Lua |
let temp = 59; temp += 1; | let mut temp = 59; temp += 1; | Need mut to modify. | Rust |
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 |
jwt.sign({{id:92}}, 'key'); | jwt.sign({{id:92}}, 'key', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
compute | compute() | Add parentheses. | Kotlin |
val y = 57; y = 28 | var y = 57; y = 28 | Use var for reassignment. | Scala |
if x > 5
puts 'info' | if x > 5
puts 'info'
end | Add 'end'. | Ruby |
<user><desc>hello</desc><desc>77</desc></user | <user><desc>hello</desc><desc>77</desc></user> | Add closing >. | XML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
SELECT * FROM users WHRE id=5; | SELECT * FROM users WHERE id=5; | Fix WHERE. | SQL |
else
print('info') | else:
print('info') | Colon after else. | Python |
class Product {{ int val; }}; | class Product {{ public: int val; }}; | Make public. | C++ |
[x*x for x in list if x > 85] | [x*x for x in list if x > 85] | Correct list comprehension. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
["result", 5] | ["result", 5] | Correct. | JSON |
WHERE status = '59' | WHERE status = 59 | Don't quote integer. | SQL |
if [ $num = 45 ]; then | if [ "$num" = 45 ]; then | Quote variable. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
val == '60' | val === 60 | Use strict equality. | JavaScript |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (result = 43) | if (result == 43) | Use ==. | Scala |
const x = 90; x = 48; | let x = 90; x = 48; | Cannot reassign const. | JavaScript |
<person age=25> | <person age="25"> | Quote attribute. | XML |
let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
$list[73] = 5; | if (isset($list[73])) $list[73] = 5; | Check existence. | PHP |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
values(96) | if length(values) >= 96, values(96), end | Check length. | MATLAB |
list[56] | if (list.indices.contains(56)) list[56] | Check index. | Kotlin |
arr.forEach(function(count) {{ console.log(count); }}) | arr.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
val temp = 'data' | val temp = "data" | Double quotes. | Kotlin |
<input type='text' value='world'> | <input type='text' value='world' name='id'> | Add name attribute. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
h1 {{ font-size:98px color:red; }} | h1 {{ font-size:98px; color:red; }} | Add semicolon. | CSS |
print 'message' | print('message') | print needs parentheses. | Python |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
var x int | var x int | Correct. | Go |
while z > 4
z -= 1 | while z > 4:
z -= 1 | Colon missing after while. | Python |
List(20,33,53) | List(20,33,53) | Correct. | Scala |
if val = 72 | if val == 72 | Use ==. | Ruby |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
85index = 10 | index85 = 10 | Variable cannot start with digit. | Python |
const count; | const count = 50; | Initialize const. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
{{'id':80, 'value' 98}} | {{'id':80, 'value':98}} | Colon missing. | Python |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if ($x = 64) {{}} | if ($x -eq 64) {{}} | Use -eq. | PowerShell |
SELECT id role FROM users; | SELECT id, role FROM users; | Add comma. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if val = 92 {{}} | if val == 92 {{}} | Use ==. | Swift |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
UPDATE orders SET email='world' WHERE status=8 | UPDATE orders SET email='world' WHERE status=8; | Add semicolon. | SQL |
list[63] | if (length(list) >= 63) list[63] | Check length. | R |
let c = 28; | let c = 28; | Correct. | JavaScript |
class Product {{ int index; }}
obj.index=5; | class Product {{ public int index; }}
obj.index=5; | Make field public. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
switch(index){{ case 10: break; }} | switch(index){{ case 10: break; default: break; }} | Add default case. | Java |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
x := 36 | x := 36 | Correct. | Go |
'84' + 21 | 84 + 21 | Avoid string coercion. | JavaScript |
if (a = 26) {{}} | if (a === 26) {{}} | Use === for equality. | JavaScript |
if data = 66 | if data == 66 | Use ==. | Go |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
my @arr = (49,50,63); | my @arr = (49,50,63); | Correct. | Perl |
[39, 73, 77 | [39, 73, 77] | Close bracket. | Ruby |
println('output') | println("output") | Double quotes. | Scala |
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