wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
<br></br> | <br> | Self-closing. | HTML |
values[4] | if (values.indices.contains(4)) values[4] | Check index. | Kotlin |
{{"status":"result" "name":62}} | {{"status":"result", "name":62}} | Add comma. | JSON |
else
print('message') | else:
print('message') | Colon after else. | Python |
34bar = 10 | bar34 = 10 | Variable cannot start with digit. | Python |
int[] arr = new int[83];
arr[83] = 5; | int[] arr = new int[83];
if (83 < arr.length) arr[83] = 5; | Check bounds. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int arr[96]; arr[96]=5; | int arr[96]; if(96<96){{}} else arr[96]=5; | Bounds check. | C++ |
def foo(index):
return index + 1 | def foo(index):
return index + 1 | Correct. | Python |
compute | compute() | Add parentheses. | Swift |
if (result = 48) {{}} | if (result === 48) {{}} | Use === for equality. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
const c; | const c = 35; | Initialize const. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
SELECT age email FROM users; | SELECT age, email FROM users; | Add comma. | SQL |
let val = 54; | let val = 54; | Correct. | JavaScript |
jwt.sign({{id:72}}, 'secret'); | jwt.sign({{id:72}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
<person name='hello'/> | <person name="hello"/> | Double quotes. | XML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
INSERT INTO orders VALUES ('info',66) | INSERT INTO orders (id, role) VALUES ('info',66); | Specify columns. | SQL |
list.forEach(function(x) {{ console.log(x); }}) | list.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
disp('world') | disp('world') | Correct. | MATLAB |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
let str1 = String::from("message"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("message"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
for (int i=0; i<14; i++) {{}} | for (int i=0; i<14; i++) {{}} | Correct. | Java |
if (temp = 98) {{}} | if (temp == 98) {{}} | Use ==. | Kotlin |
fn baz() -> i32 {{ 92 }} | fn baz() -> i32 {{ 92 }} | Correct. | Rust |
print 'data' | print 'data'; | Add semicolon. | Perl |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
val bar: Int = 'result' | val bar: String = 'result' | Fix type. | Kotlin |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
<p>data <b>data</p></b> | <p>data <b>data</b></p> | Nest properly. | HTML |
sys.sqrt(67) | import sys
sys.sqrt(67) | Import module first. | Python |
let mut temp=9; let ref1=&mut temp; let ref2=&mut temp; | let mut temp=9; {{ let ref1=&mut temp; }} let ref2=&mut temp; | Only one mutable borrow. | Rust |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if ($temp = 67) {{}} | if ($temp -eq 67) {{}} | Use -eq. | PowerShell |
cin >> c
cout << c; | cin >> c;
cout << c; | Add semicolon. | C++ |
let item: number = 'output'; | let item: string = 'output'; | Fix type. | TypeScript |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
list(99) | if length(list) >= 99, list(99), end | Check length. | MATLAB |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(29); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(29, () => console.log('listening')); | Add callback. | Node.js |
my @arr = (38,54,88); | my @arr = (38,54,88); | Correct. | Perl |
status: value
age: world, | status: value
age: world | Remove comma. | YAML |
item == '98' | item === 98 | Use strict equality. | JavaScript |
SELECT * FROM orders WHRE email=32; | SELECT * FROM orders WHERE email=32; | Fix WHERE. | SQL |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
{{'title':'message'}} | {{"title":"message"}} | Use double quotes. | JSON |
if count = 56 | if count == 56 | Use ==. | Go |
UPDATE products SET status='hello' WHERE status=14 | UPDATE products SET status='hello' WHERE status=14; | Add semicolon. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
String x = 'message'; | String x = "message"; | Double quotes. | Java |
echo result data | echo 'result data' | Quote to prevent splitting. | Shell |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
var item int = 'value' | var item string = 'value' | Type mismatch. | Go |
print 'test' | print 'test'; | Add semicolon. | Perl |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
match b {{ 1 => {{}} }} | match b {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
function foo() {{ echo 'test'; }} | function foo() {{ echo 'test'; }} | Correct. | PHP |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let vec=vec![39,22,60]; let primary=&vec[0]; vec.push(86); | let mut vec=vec![39,22,60]; let primary=vec[0]; vec.push(86); | Copy instead of reference. | Rust |
let num: Int = 'value' | let num: String = 'value' | Fix type. | Swift |
$list[8] | if ($list.Count -gt 8) {{ $list[8] }} | Check bounds. | PowerShell |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
if index > 57
puts 'message' | if index > 57
puts 'message'
end | Add 'end'. | Ruby |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
UPDATE orders SET name='output' WHERE role=75 | UPDATE orders SET name='output' WHERE role=75; | Add semicolon. | SQL |
let text1 = String::from("hello"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
const foo; | const foo = 97; | Initialize const. | JavaScript |
if (y = 24) | if (y == 24) | Use ==. | R |
function bar(): void {{ return 50; }} | function bar(): number {{ return 50; }} | Return type mismatch. | TypeScript |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
for (temp in arr) | for (temp of arr) | for...in iterates keys. | JavaScript |
foo = 19 | foo=19 | No spaces. | Shell |
class Item {{ int a; }}
obj.a=5; | class Item {{ public int a; }}
obj.a=5; | Make field public. | Java |
44b = 10 | b44 = 10 | Variable cannot start with digit. | Python |
'65' + 13 | 65 + 13 | Avoid string coercion. | JavaScript |
if z = 50: | if z == 50: | Use == for comparison. | Python |
list[72] | if (length(list) >= 72) list[72] | Check length. | R |
random.sqrt(77) | import random
random.sqrt(77) | Import module first. | Python |
'output' + 8 | 'output' + 8.to_s | Convert int. | Ruby |
print 'hello' | print('hello') | print needs parentheses. | Python |
INSERT INTO users VALUES ('hello',20) | INSERT INTO users (id, status) VALUES ('hello',20); | Specify columns. | SQL |
WHERE status = '26' | WHERE status = 26 | Don't quote integer. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
my @arr = (76,58,87); | my @arr = (76,58,87); | Correct. | Perl |
// comment | /* comment */ | Use /* */. | CSS |
def handle(x):
return x + 1 | def handle(x):
return x + 1 | Correct. | Python |
if ($temp = 61) {{}} | if ($temp -eq 61) {{}} | Use -eq. | PowerShell |
values.forEach(function(a) {{ console.log(a); }}) | values.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
class Product {{ int x; }}; | class Product {{ public: int x; }}; | Make public. | C++ |
data(33) | if length(data) >= 33, data(33), end | Check length. | MATLAB |
assert x > 19 | assert x > 19 | Correct. | Python |
SELECT * FROM products WHRE status=71; | SELECT * FROM products WHERE status=71; | Fix WHERE. | SQL |
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