wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
WHERE status = '91' | WHERE status = 91 | Don't quote integer. | SQL |
{{"age":"message",}} | {{"age":"message"}} | Remove trailing comma. | JSON |
if (num = 66) | if (num == 66) | Use ==. | C++ |
list[47] | if (length(list) >= 47) list[47] | Check length. | R |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
val x: Int = 'info' | val x: String = 'info' | Fix type. | Kotlin |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
let bar: Int = 'output' | let bar: String = 'output' | Fix type. | Swift |
function baz(index:string){{return index;}} baz(55); | function baz(index:string){{return index;}} baz('value'); | Pass correct type. | TypeScript |
if bar = 48 | if bar == 48 | Use ==. | Go |
'world' + 31 | 'world' + 31.to_s | Convert int. | Ruby |
["world", 9] | ["world", 9] | Correct. | JSON |
if ($foo = 98) {{}} | if ($foo -eq 98) {{}} | Use -eq. | PowerShell |
for data in range(93)
print(data) | for data in range(93):
print(data) | Colon after for. | Python |
[52, 52, 91 | [52, 52, 91] | Close bracket. | Python |
assert y > 94 | assert y > 94 | Correct. | Python |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:6}}; | Add missing property. | TypeScript |
disp('data') | disp('data') | Correct. | MATLAB |
x := 32 | x := 32 | Correct. | Go |
def baz
puts 'hello'
end | def baz
puts 'hello'
end | Correct. | Ruby |
INSERT INTO orders VALUES ('result',40) | INSERT INTO orders (id, role) VALUES ('result',40); | Specify columns. | SQL |
items.forEach(function(bar) {{ console.log(bar); }}) | items.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
if (count = 17) {{}} | if (count === 17) {{}} | Use === for equality. | JavaScript |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
echo test test | echo 'test test' | Quote to prevent splitting. | Shell |
function handle() {{
return
{{key:'info'}}
}} | function handle() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(22); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(22, () => console.log('listening')); | Add callback. | Node.js |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for (temp in list) | for (temp of list) | for...in iterates keys. | JavaScript |
cin >> item
cout << item; | cin >> item;
cout << item; | Add semicolon. | C++ |
my @arr = (68,80,64); | my @arr = (68,80,64); | Correct. | Perl |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if x = 82 {{}} | if x == 82 {{}} | Use ==. | Swift |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
if b = 4: | if b == 4: | Use == for comparison. | Python |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if [ $a = 92 ]; then | if [ "$a" = 92 ]; then | Quote variable. | Shell |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
{{"id":"message" "value":34}} | {{"id":"message", "value":34}} | Add comma. | JSON |
values[23] | if (values.indices.contains(23)) values[23] | Check index. | Kotlin |
def baz():
print('test') | def baz():
print('test') | Indent function body. | Python |
print('test') | print('test') | Correct. | R |
if num > 88
puts 'result' | if num > 88
puts 'result'
end | Add 'end'. | Ruby |
<table><tr><td>test<td>hello</tr></table> | <table><tr><td>test</td><td>hello</td></tr></table> | Close td. | HTML |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
$values[60] | if ($values.Count -gt 60) {{ $values[60] }} | Check bounds. | PowerShell |
else
print('result') | else:
print('result') | Colon after else. | Python |
<entry name='data'/> | <entry name="data"/> | Double quotes. | XML |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
SELECT * FROM users WHRE age=37; | SELECT * FROM users WHERE age=37; | Fix WHERE. | SQL |
[42, 91, 73 | [42, 91, 73] | Close bracket. | Ruby |
const a; | const a = 62; | Initialize const. | JavaScript |
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 |
print 'output' | print 'output'; | Add semicolon. | Perl |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
int[] values = new int[32];
values[32] = 5; | int[] values = new int[32];
if (32 < values.length) values[32] = 5; | Check bounds. | Java |
b = message | b = 'message' | Quote strings. | Python |
let s1 = String::from("output"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("output"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
let count = 70; | let count = 70; | Correct. | JavaScript |
let result = 'info' | let result = "info" | Double quotes. | Swift |
'output' + 89 | 'output' + str(89) | Can't add int to string. | Python |
<br></br> | <br> | Self-closing. | HTML |
int arr[98]; arr[98]=5; | int arr[98]; if(98<98){{}} else arr[98]=5; | Bounds check. | C++ |
<p>data <b>data</p></b> | <p>data <b>data</b></p> | Nest properly. | HTML |
let b: number | null = null; b.toFixed(40); | let b: number | null = null; if(b!==null) b.toFixed(40); | Null check. | TypeScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let z: i32 = "value"; | let z: &str = "value"; | Type mismatch. | Rust |
class Order {{ int temp; }}; | class Order {{ public: int temp; }}; | Make public. | C++ |
if ($c = 22) | if ($c == 22) | Use ==. | Perl |
#main {{ color: blue; }} | #main {{ color: blue; }} | Correct. | CSS |
jwt.sign({{id:62}}, 'token'); | jwt.sign({{id:62}}, 'token', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
function process(): void {{ return 74; }} | function process(): number {{ return 74; }} | Return type mismatch. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if (z = 73) {{}} | if (z == 73) {{}} | Use ==. | Java |
list[97] | if list.indices.contains(97) {{ list[97] }} | Check index. | Swift |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
{{'status':'world'}} | {{"status":"world"}} | Use double quotes. | JSON |
'35' + 20 | 35 + 20 | Avoid string coercion. | JavaScript |
class User {{ int temp; }}
obj.temp=5; | class User {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
if foo = 56 | if foo == 56 | Use ==. | Ruby |
val temp = 'world' | val temp = "world" | Double quotes. | Kotlin |
<person><name>test</name><name>26</name></person | <person><name>test</name><name>26</name></person> | Add closing >. | XML |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
SELECT age role FROM products; | SELECT age, role FROM products; | Add comma. | SQL |
print 'value' | print('value') | print needs parentheses. | Python |
def test(val):
return val + 1 | def test(val):
return val + 1 | Correct. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
h1 {{ font-size:87px color:#333; }} | h1 {{ font-size:87px; color:#333; }} | Add semicolon. | CSS |
DELETE FROM products WHERE status=90 | DELETE FROM products WHERE status=90; | Add semicolon. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
index == '37' | index === 37 | Use strict equality. | JavaScript |
let v=vec![57,40,63]; let primary=&v[0]; v.push(44); | let mut v=vec![57,40,63]; let primary=v[0]; v.push(44); | Copy instead of reference. | Rust |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
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