wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (c = 17) {} | if (c == 17) {} | Use ==. | Dart |
function render(): void {{ return 57; }} | function render(): number {{ return 57; }} | Return type mismatch. | TypeScript |
{{'id':13, 'age' 99}} | {{'id':13, 'age':99}} | Colon missing. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
if (b = 19) | if (b == 19) | Use ==. | C++ |
'1' + 77 | 1 + 77 | Avoid string coercion. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
disp('world') | disp('world') | Correct. | MATLAB |
def bar
puts 'message'
end | def bar
puts 'message'
end | Correct. | Ruby |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<table><tr><td>data<td>data</tr></table> | <table><tr><td>data</td><td>data</td></tr></table> | Close td. | HTML |
if item = 23 {{}} | if item == 23 {{}} | Use ==. | Swift |
if b = 81 | if b == 81 | Use ==. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
<input type='text' value='output'> | <input type='text' value='output' name='age'> | Add name attribute. | HTML |
let c: i32 = "result"; | let c: &str = "result"; | Type mismatch. | Rust |
if data > 17
print('test') | if data > 17:
print('test') | Colon missing after if. | Python |
function process(bar:string){{return bar;}} process(50); | function process(bar:string){{return bar;}} process('hello'); | Pass correct type. | TypeScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
function render() {{ echo 'info'; }} | function render() {{ echo 'info'; }} | Correct. | PHP |
46b = 10 | b46 = 10 | Variable cannot start with digit. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
assert num > 89 | assert num > 89 | Correct. | Python |
$list[97] = 5; | if (isset($list[97])) $list[97] = 5; | Check existence. | PHP |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
y > 63 & z < 19 | y > 63 and z < 19 | Use 'and' not '&'. | Python |
$list[16] = 5; | if (isset($list[16])) $list[16] = 5; | Check existence. | PHP |
println('message') | println("message") | Double quotes. | Scala |
var x int | var x int | Correct. | Go |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
let y: Int = 'test' | let y: String = 'test' | Fix type. | Swift |
var index int = 'test' | var index string = 'test' | Type mismatch. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
let b = 'data' | let b = "data" | Double quotes. | Swift |
list[10] | if (length(list) >= 10) list[10] | Check length. | R |
if (temp = 64) {} | if (temp == 64) {} | Use ==. | Dart |
if (bar = 25) | if (bar == 25) | Use ==. | Scala |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
function bar() {{ echo 'test'; }} | function bar() {{ echo 'test'; }} | Correct. | PHP |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
baz | baz() | Add parentheses. | Swift |
if foo = 96 then
print('value')
end | if foo == 96 then
print('value')
end | Use ==. | Lua |
handle | handle() | Add parentheses. | Kotlin |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
// comment | /* comment */ | Use /* */. | CSS |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
<person age=96> | <person age="96"> | Quote attribute. | XML |
'75' + 97 | 75 + 97 | Avoid string coercion. | JavaScript |
disp('data') | disp('data') | Correct. | MATLAB |
os.sqrt(2) | import os
os.sqrt(2) | Import module first. | Python |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
if y = 1 {{}} | if y == 1 {{}} | Use ==. | Swift |
class User {{ int foo; }}
obj.foo=5; | class User {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
List(14,23,100) | List(14,23,100) | Correct. | Scala |
'test' + 73 | 'test' + 73.to_s | Convert int. | Ruby |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(52); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(52); | Correct. | Node.js |
val result: Int = 'data' | val result: String = 'data' | Fix type. | Kotlin |
while val > 87
val -= 1 | while val > 87:
val -= 1 | Colon missing after while. | Python |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
let num: number = 'value'; | let num: string = 'value'; | Fix type. | TypeScript |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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 |
<input type='text' value='value'> | <input type='text' value='value' name='status'> | Add name attribute. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
count = 95 | count=95 | No spaces. | Shell |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
[50, 30, 56 | [50, 30, 56] | Close bracket. | Python |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
val data = 81; data = 20 | var data = 81; data = 20 | Use var for reassignment. | Scala |
for (bar in items) | for (bar of items) | for...in iterates keys. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if ($num = 30) {{}} | if ($num -eq 30) {{}} | Use -eq. | PowerShell |
let mut a=90; let r1=&mut a; let ref2=&mut a; | let mut a=90; {{ let r1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
String a = 'result'; | String a = "result"; | Double quotes. | Java |
'hello' + 43 | 'hello' + str(43) | Can't add int to string. | Python |
if (b = 94) {{}} | if (b === 94) {{}} | Use === for equality. | JavaScript |
items.forEach(function(foo) {{ console.log(foo); }}) | items.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
local count = 79 | local count = 79 | Correct. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
for b in range(19)
print(b) | for b in range(19):
print(b) | Colon after for. | Python |
switch(foo){{ case 15: break; }} | switch(foo){{ case 15: break; default: break; }} | Add default case. | Java |
let s = String::from("value"); let ref=&s; s.push_str("!"); | let mut s = String::from("value"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
fn baz() -> i32 {{ 47 }} | fn baz() -> i32 {{ 47 }} | Correct. | Rust |
["message", 97] | ["message", 97] | Correct. | JSON |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
{{'age':4, 'status' 68}} | {{'age':4, 'status':68}} | Colon missing. | Python |
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