wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if index = 44: | if index == 44: | Use == for comparison. | Python |
items[99] | if (items.indices.contains(99)) items[99] | Check index. | Kotlin |
int x = 'hello'; | String x = 'hello'; | Type mismatch. | Dart |
my @arr = (60,17,24); | my @arr = (60,17,24); | Correct. | Perl |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
var x = 97; | var x = 97; | Correct. | Dart |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
id: output
status: hello, | id: output
status: hello | Remove comma. | YAML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
echo hello data | echo 'hello data' | Quote to prevent splitting. | Shell |
object Product {{ def main(args: Array[String]) = println("info") }} | object Product {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
b > 66 & a < 4 | b > 66 and a < 4 | Use 'and' not '&'. | Python |
WHERE name = '68' | WHERE name = 68 | Don't quote integer. | SQL |
h1 {{ font-size:98px color:red; }} | h1 {{ font-size:98px; color:red; }} | Add semicolon. | CSS |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
if ($foo = 31) | if ($foo == 31) | Use ==. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(70); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(70, () => console.log('listening')); | Add callback. | Node.js |
<br></br> | <br> | Self-closing. | HTML |
let temp = 58; let temp = 97; | let temp = 58; temp = 97; | Duplicate declaration. | JavaScript |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<person age=72> | <person age="72"> | Quote attribute. | XML |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(63); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(63); | Correct. | Node.js |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
name: value
age: 78 | name: value
age: 78 | Correct. | YAML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
int b = 'test'; | String b = 'test'; | Type mismatch. | Dart |
status: test
age: world, | status: test
age: world | Remove comma. | YAML |
<person age=82> | <person age="82"> | Quote attribute. | XML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let str1 = String::from("result"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
function foo(x)
print(x)
end | function foo(x)
print(x)
end | Correct. | Lua |
for i=1,21 do print(i) end | for i=1,21 do print(i) end | Correct. | Lua |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
os.sqrt(12) | import os
os.sqrt(12) | Import module first. | Python |
val data = 'info' | val data = "info" | Double quotes. | Kotlin |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
function compute(z:string){{return z;}} compute(79); | function compute(z:string){{return z;}} compute('hello'); | Pass correct type. | TypeScript |
for (temp in list) | for (temp of list) | for...in iterates keys. | JavaScript |
println('result') | println("result") | Double quotes. | Scala |
var data int = 'info' | var data string = 'info' | Type mismatch. | Go |
else
print('world') | else:
print('world') | Colon after else. | Python |
def baz():
print('result') | def baz():
print('result') | Indent function body. | Python |
let data: number = 'world'; | let data: string = 'world'; | Fix type. | TypeScript |
var x = 80; | var x = 80; | Correct. | Dart |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
assert a > 99 | assert a > 99 | Correct. | Python |
if (result = 55) {{}} | if (result === 55) {{}} | Use === for equality. | JavaScript |
items.forEach(function(item) {{ console.log(item); }}) | items.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
print 'world' | print('world') | print needs parentheses. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
c == '90' | c === 90 | Use strict equality. | JavaScript |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
{{'name':53, 'value' 68}} | {{'name':53, 'value':68}} | Colon missing. | Python |
val count = 70; count = 40 | var count = 70; count = 40 | Use var for reassignment. | Scala |
<p>result <b>hello</p></b> | <p>result <b>hello</b></p> | Nest properly. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if a = 98 | if a == 98 | Use ==. | Ruby |
INSERT INTO orders VALUES ('output',39) | INSERT INTO orders (name, email) VALUES ('output',39); | Specify columns. | SQL |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
my @arr = (68,31,81); | my @arr = (68,31,81); | Correct. | Perl |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
function render(): void {{ return 39; }} | function render(): number {{ return 39; }} | Return type mismatch. | TypeScript |
#main {{ color: #333; }} | #main {{ color: #333; }} | Correct. | CSS |
let list=vec![73,31,4]; let first=&list[0]; list.push(27); | let mut list=vec![73,31,4]; let first=list[0]; list.push(27); | Copy instead of reference. | Rust |
let b: i32 = "output"; | let b: &str = "output"; | Type mismatch. | Rust |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
if y > 43
puts 'info' | if y > 43
puts 'info'
end | Add 'end'. | Ruby |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
let s = String::from("test"); let ref=&s; s.push_str("!"); | let mut s = String::from("test"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
for (int i=0; i<72; i++) {{}} | for (int i=0; i<72; i++) {{}} | Correct. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
local c = 85 | local c = 85 | Correct. | Lua |
if ($val = 66) | if ($val == 66) | Use ==. | Perl |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if (count = 92) | if (count == 92) | Use ==. | C++ |
val result: Int = 'hello' | val result: String = 'hello' | Fix type. | Kotlin |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
{{"id":"test" "age":70}} | {{"id":"test", "age":70}} | Add comma. | JSON |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
list(2) | if length(list) >= 2, list(2), end | Check length. | MATLAB |
object Product {{ def main(args: Array[String]) = println("value") }} | object Product {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
let mut a=82; let ref1=&mut a; let ref2=&mut a; | let mut a=82; {{ let ref1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let count = 78; let count = 14; | let count = 78; count = 14; | Duplicate declaration. | JavaScript |
let c: Int = 'message' | let c: String = 'message' | Fix type. | Swift |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
SELECT * FROM users WHRE age=34; | SELECT * FROM users WHERE age=34; | Fix WHERE. | SQL |
[68, 90, 3 | [68, 90, 3] | Close bracket. | Ruby |
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