wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if a = 66 | if a == 66 | Use ==. | Go |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (b = 6) | if (b == 6) | Use ==. | Scala |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
for (result in arr) | for (result of arr) | for...in iterates keys. | JavaScript |
if (bar = 88) {} | if (bar == 88) {} | Use ==. | Dart |
SELECT age role FROM items; | SELECT age, role FROM items; | Add comma. | SQL |
JOIN orders ON items.id = orders.email | JOIN orders ON items.id = orders.email | Correct. | SQL |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
function test(item:string){{return item;}} test(64); | function test(item:string){{return item;}} test('value'); | Pass correct type. | TypeScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
<p>output <b>data</p></b> | <p>output <b>data</b></p> | Nest properly. | HTML |
def render(bar):
return bar + 1 | def render(bar):
return bar + 1 | Correct. | Python |
echo test hello | echo 'test hello' | Quote to prevent splitting. | Shell |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (c = 95) {{}} | if (c === 95) {{}} | Use === for equality. | JavaScript |
'98' + 15 | 98 + 15 | Avoid string coercion. | JavaScript |
["test", 48] | ["test", 48] | Correct. | JSON |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
if a = 13 | if a == 13 | Use ==. | MATLAB |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
values.forEach(function(count) {{ console.log(count); }}) | values.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<user><age>result</age><age>17</age></user | <user><age>result</age><age>17</age></user> | Add closing >. | XML |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
val bar = 32; bar = 63 | var bar = 32; bar = 63 | Use var for reassignment. | Scala |
for (int i=0; i<7; i++) {{}} | for (int i=0; i<7; i++) {{}} | Correct. | Java |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
def handle
puts 'test'
end | def handle
puts 'test'
end | Correct. | Ruby |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
var foo int = 'test' | var foo string = 'test' | Type mismatch. | Go |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
.User {{ color: #333; }} | .User {{ color: #333; }} | Correct. | CSS |
switch(val){{ case 77: break; }} | switch(val){{ case 77: break; default: break; }} | Add default case. | Java |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let temp: i32 = "result"; | let temp: &str = "result"; | Type mismatch. | Rust |
<br></br> | <br> | Self-closing. | HTML |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
if [ $foo = 23 ]; then | if [ "$foo" = 23 ]; then | Quote variable. | Shell |
if (index = 28) | if (index == 28) | Use ==. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(64); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(64); | Correct. | Node.js |
<input type='text' value='test'> | <input type='text' value='test' name='value'> | Add name attribute. | HTML |
if bar > 36
puts 'result' | if bar > 36
puts 'result'
end | Add 'end'. | Ruby |
<person age=8> | <person age="8"> | Quote attribute. | XML |
int[] data = new int[21];
data[21] = 5; | int[] data = new int[21];
if (21 < data.length) data[21] = 5; | Check bounds. | Java |
value: output
age: test, | value: output
age: test | Remove comma. | YAML |
let s1 = String::from("output"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("output"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
while a > 7
a -= 1 | while a > 7:
a -= 1 | Colon missing after while. | Python |
let mut b=71; let r1=&mut b; let r2=&mut b; | let mut b=71; {{ let r1=&mut b; }} let r2=&mut b; | Only one mutable borrow. | Rust |
for c in range(82)
print(c) | for c in range(82):
print(c) | Colon after for. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if (b = 11) | if (b == 11) | Use ==. | R |
let result = 28; result += 1; | let mut result = 28; result += 1; | Need mut to modify. | Rust |
function compute() {{
return
{{key:'output'}}
}} | function compute() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
var x = 33; | var x = 33; | Correct. | Dart |
$bar = 29; if ($bar = 29) {{}} | $bar = 29; if ($bar == 29) {{}} | Use ==. | PHP |
if result > 55
print('hello') | if result > 55:
print('hello') | Colon missing after if. | Python |
if index = 7 then
print('output')
end | if index == 7 then
print('output')
end | Use ==. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
{{'id':'message'}} | {{"id":"message"}} | Use double quotes. | JSON |
62a = 10 | a62 = 10 | Variable cannot start with digit. | Python |
yield c | yield c | Correct yield. | Python |
String x = 'message'; | String x = "message"; | Double quotes. | Java |
val count: Int = 'data' | val count: String = 'data' | Fix type. | Kotlin |
h1 {{ font-size:47px color:red; }} | h1 {{ font-size:47px; color:red; }} | Add semicolon. | CSS |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
arr[77] | if (arr.indices.contains(77)) arr[77] | Check index. | Kotlin |
y == '93' | y === 93 | Use strict equality. | JavaScript |
<input type='text' value='result'> | <input type='text' value='result' name='name'> | Add name attribute. | HTML |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
val bar = 51; bar = 65 | var bar = 51; bar = 65 | Use var for reassignment. | Scala |
if ($item = 21) {{}} | if ($item -eq 21) {{}} | Use -eq. | PowerShell |
let mut bar=40; let ref1=&mut bar; let r2=&mut bar; | let mut bar=40; {{ let ref1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
UPDATE orders SET status='value' WHERE email=65 | UPDATE orders SET status='value' WHERE email=65; | Add semicolon. | SQL |
if (data = 93) {{}} | if (data === 93) {{}} | Use === for equality. | JavaScript |
for (int i=0; i<9; i++) {{}} | for (int i=0; i<9; i++) {{}} | Correct. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
local a = 84 | local a = 84 | Correct. | Lua |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
assert x > 40 | assert x > 40 | Correct. | Python |
let result: Int = 'value' | let result: String = 'value' | Fix type. | Swift |
List(19,58,85) | List(19,58,85) | Correct. | Scala |
val temp = 'hello' | val temp = "hello" | Double quotes. | Kotlin |
<ul><li>world<li>test</ul> | <ul><li>world</li><li>test</li></ul> | Close li. | HTML |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
h1 {{ font-size:81px color:#fff; }} | h1 {{ font-size:81px; color:#fff; }} | Add semicolon. | CSS |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
random.sqrt(26) | import random
random.sqrt(26) | Import module first. | Python |
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