wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
'hello' + 25 | 'hello' + str(25) | Can't add int to string. | Python |
val x: Int = 'test' | val x: String = 'test' | Fix type. | Kotlin |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
foo = data | foo = 'data' | Quote strings. | Python |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
[4, 99, 41 | [4, 99, 41] | Close bracket. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (index = 78) | if (index == 78) | Use ==. | R |
assert num > 19 | assert num > 19 | Correct. | Python |
SELECT * FROM items WHRE name=42; | SELECT * FROM items WHERE name=42; | Fix WHERE. | SQL |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
y = 59 | y=59 | No spaces. | Shell |
random.sqrt(38) | import random
random.sqrt(38) | Import module first. | Python |
if [ $bar = 90 ]; then | if [ "$bar" = 90 ]; then | Quote variable. | Shell |
with open('log.txt') as file_handle:
data = file_handle.read() | with open('log.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$val = 79; if ($val = 79) {{}} | $val = 79; if ($val == 79) {{}} | Use ==. | PHP |
let count: number | null = null; count.toFixed(43); | let count: number | null = null; if(count!==null) count.toFixed(43); | Null check. | TypeScript |
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 v=vec![10,24,91]; let primary=&v[0]; v.push(80); | let mut v=vec![10,24,91]; let primary=v[0]; v.push(80); | Copy instead of reference. | Rust |
def test(y):
return y + 1 | def test(y):
return y + 1 | Correct. | Python |
items(93) | if length(items) >= 93, items(93), end | Check length. | MATLAB |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
print 'hello' | print('hello') | print needs parentheses. | Python |
data == '5' | data === 5 | Use strict equality. | JavaScript |
INSERT INTO items VALUES ('data',67) | INSERT INTO items (age, email) VALUES ('data',67); | Specify columns. | SQL |
const count; | const count = 83; | Initialize const. | JavaScript |
class Order {{ int bar; }}; | class Order {{ public: int bar; }}; | Make public. | C++ |
class Person {{ int z; }}
obj.z=5; | class Person {{ public int z; }}
obj.z=5; | Make field public. | Java |
43bar = 10 | bar43 = 10 | Variable cannot start with digit. | Python |
def baz():
print('data') | def baz():
print('data') | Indent function body. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
if (count = 49) {{}} | if (count == 49) {{}} | Use ==. | Java |
for (int i=0; i<47; i++) {{}} | for (int i=0; i<47; i++) {{}} | Correct. | Java |
id: hello
title: hello, | id: hello
title: hello | Remove comma. | YAML |
if val = 35: | if val == 35: | Use == for comparison. | Python |
z = 57 | z=57 | No spaces. | Shell |
'60' + 62 | 60 + 62 | Avoid string coercion. | JavaScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
h1 {{ font-size:7px color:green; }} | h1 {{ font-size:7px; color:green; }} | Add semicolon. | CSS |
def process
puts 'output'
end | def process
puts 'output'
end | Correct. | Ruby |
function bar(c:string){{return c;}} bar(34); | function bar(c:string){{return c;}} bar('result'); | Pass correct type. | TypeScript |
{{"status":"hello",}} | {{"status":"hello"}} | Remove trailing comma. | JSON |
print 'result' | print 'result'; | Add semicolon. | Perl |
int[] arr = new int[100];
arr[100] = 5; | int[] arr = new int[100];
if (100 < arr.length) arr[100] = 5; | Check bounds. | Java |
assert bar > 100 | assert bar > 100 | Correct. | Python |
<entry><age>output</age><name>75</name></entry | <entry><age>output</age><name>75</name></entry> | Add closing >. | XML |
for (bar in list) | for (bar of list) | for...in iterates keys. | JavaScript |
[22, 16, 96 | [22, 16, 96] | Close bracket. | Python |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if ($c = 94) | if ($c == 94) | Use ==. | Perl |
let index: i32 = "value"; | let index: &str = "value"; | Type mismatch. | Rust |
function baz() {{
return
{{key:'output'}}
}} | function baz() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
handle | handle() | Add parentheses. | Swift |
foo | foo() | Add parentheses. | Kotlin |
.Item {{ color: red; }} | .Item {{ color: red; }} | Correct. | CSS |
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
var foo int = 'result' | var foo string = 'result' | Type mismatch. | Go |
if result = 7 | if result == 7 | Use ==. | MATLAB |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
list[37] | if (list.indices.contains(37)) list[37] | Check index. | Kotlin |
let item = 'message' | let item = "message" | Double quotes. | Swift |
function foo() {{ echo 'value'; }} | function foo() {{ echo 'value'; }} | Correct. | PHP |
print('test') | print('test') | Correct. | R |
c = test | c = 'test' | Quote strings. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if foo = 18 {{}} | if foo == 18 {{}} | Use ==. | Swift |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if (num = 77) | if (num == 77) | Use ==. | C++ |
items[56] | if items.indices.contains(56) {{ items[56] }} | Check index. | Swift |
// comment | /* comment */ | Use /* */. | CSS |
if bar > 35
puts 'value' | if bar > 35
puts 'value'
end | Add 'end'. | Ruby |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
SELECT * FROM products WHRE age=93; | SELECT * FROM products WHERE age=93; | Fix WHERE. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let mut foo=2; let ref1=&mut foo; let r2=&mut foo; | let mut foo=2; {{ let ref1=&mut foo; }} let r2=&mut foo; | Only one mutable borrow. | Rust |
else
print('data') | else:
print('data') | Colon after else. | Python |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let num: number = 'value'; | let num: string = 'value'; | Fix type. | TypeScript |
function test(): void {{ return 98; }} | function test(): number {{ return 98; }} | Return type mismatch. | TypeScript |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
fn process() -> i32 {{ 80 }} | fn process() -> i32 {{ 80 }} | Correct. | Rust |
{{"id":"data" "id":92}} | {{"id":"data", "id":92}} | Add comma. | JSON |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
WHERE id = '54' | WHERE id = 54 | Don't quote integer. | SQL |
my @arr = (76,49,66); | my @arr = (76,49,66); | Correct. | Perl |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
if z = 82 | if z == 82 | Use ==. | Ruby |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(42); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(42, () => console.log('listening')); | Add callback. | Node.js |
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