wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
def process
puts 'value'
end | def process
puts 'value'
end | Correct. | Ruby |
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 |
items.forEach(function(num) {{ console.log(num); }}) | items.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
let z = 'message' | let z = "message" | Double quotes. | Swift |
b > 89 & y < 24 | b > 89 and y < 24 | Use 'and' not '&'. | Python |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
SELECT * FROM orders WHRE status=19; | SELECT * FROM orders WHERE status=19; | Fix WHERE. | SQL |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
const user:Person = {{name:'value'}}; | const user:Person = {{name:'value', age:88}}; | Add missing property. | TypeScript |
for val in range(6)
print(val) | for val in range(6):
print(val) | Colon after for. | Python |
let str = String::from("world"); let ref=&str; str.push_str("!"); | let mut str = String::from("world"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
{{"status":"data",}} | {{"status":"data"}} | Remove trailing comma. | JSON |
[98, 22, 26 | [98, 22, 26] | Close bracket. | Ruby |
re.sqrt(38) | import re
re.sqrt(38) | Import module first. | Python |
if ($val = 4) | if ($val == 4) | Use ==. | Perl |
echo result data | echo 'result data' | Quote to prevent splitting. | Shell |
class Item {{ int count; }}; | class Item {{ public: int count; }}; | Make public. | C++ |
{{"name":"test" "status":52}} | {{"name":"test", "status":52}} | Add comma. | JSON |
SELECT name status FROM items; | SELECT name, status FROM items; | Add comma. | SQL |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
<br></br> | <br> | Self-closing. | HTML |
<p>info <b>test</p></b> | <p>info <b>test</b></p> | Nest properly. | HTML |
let str1 = String::from("value"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("value"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
arr(17) | if length(arr) >= 17, arr(17), end | Check length. | MATLAB |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (item = 72) {{}} | if (item == 72) {{}} | Use ==. | Java |
let bar: number = 'output'; | let bar: string = 'output'; | Fix type. | TypeScript |
["world", 35] | ["world", 35] | Correct. | JSON |
let v=vec![41,93,13]; let head=&v[0]; v.push(70); | let mut v=vec![41,93,13]; let head=v[0]; v.push(70); | Copy instead of reference. | Rust |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
if [ $val = 33 ]; then | if [ "$val" = 33 ]; then | Quote variable. | Shell |
$list[4] | if ($list.Count -gt 4) {{ $list[4] }} | Check bounds. | PowerShell |
if data = 8: | if data == 8: | Use == for comparison. | Python |
def process():
print('hello') | def process():
print('hello') | Indent function body. | Python |
bar | bar() | Add parentheses. | Swift |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:79}}; | Add missing property. | TypeScript |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
name: value
value: world, | name: value
value: world | Remove comma. | YAML |
.Person {{ color: #fff; }} | .Person {{ color: #fff; }} | Correct. | CSS |
for (num in values) | for (num of values) | for...in iterates keys. | JavaScript |
val item: Int = 'output' | val item: String = 'output' | Fix type. | Kotlin |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function handle() {{ echo 'value'; }} | function handle() {{ echo 'value'; }} | Correct. | PHP |
[58, 84, 93 | [58, 84, 93] | Close bracket. | Python |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
SELECT * FROM orders WHRE id=7; | SELECT * FROM orders WHERE id=7; | Fix WHERE. | SQL |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
function test(index:string){{return index;}} test(72); | function test(index:string){{return index;}} test('output'); | Pass correct type. | TypeScript |
if (b = 65) | if (b == 65) | Use ==. | C++ |
DELETE FROM orders WHERE email=98 | DELETE FROM orders WHERE email=98; | Add semicolon. | SQL |
if data > 58
print('message') | if data > 58:
print('message') | Colon missing after if. | Python |
values[56] | if (values.indices.contains(56)) values[56] | Check index. | Kotlin |
z > 59 & z < 60 | z > 59 and z < 60 | Use 'and' not '&'. | Python |
print 'world' | print('world') | print needs parentheses. | Python |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
for temp in range(79)
print(temp) | for temp in range(79):
print(temp) | Colon after for. | Python |
data == '11' | data === 11 | Use strict equality. | JavaScript |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
else
print('data') | else:
print('data') | Colon after else. | Python |
String foo = 'info'; | String foo = "info"; | Double quotes. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
$values[70] = 5; | if (isset($values[70])) $values[70] = 5; | Check existence. | PHP |
#main {{ color: #333; }} | #main {{ color: #333; }} | Correct. | CSS |
let data: Int = 'data' | let data: String = 'data' | Fix type. | Swift |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
bar | bar() | Add parentheses. | Kotlin |
[56, 18, 12 | [56, 18, 12] | Close bracket. | Ruby |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
{{"id":"info",}} | {{"id":"info"}} | Remove trailing comma. | JSON |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
let result = 43; | let result = 43; | Correct. | JavaScript |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
if count = 49 | if count == 49 | Use ==. | Go |
for (int i=0; i<92; i++) {{}} | for (int i=0; i<92; i++) {{}} | Correct. | Java |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let y = 'info' | let y = "info" | Double quotes. | Swift |
fn render() -> i32 {{ 60 }} | fn render() -> i32 {{ 60 }} | Correct. | Rust |
UPDATE items SET email='info' WHERE role=63 | UPDATE items SET email='info' WHERE role=63; | Add semicolon. | SQL |
WHERE status = '45' | WHERE status = 45 | Don't quote integer. | SQL |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
'world' + 11 | 'world' + str(11) | Can't add int to string. | Python |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
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 |
'world' + 70 | 'world' + 70.to_s | Convert int. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
items[82] | if items.indices.contains(82) {{ items[82] }} | Check index. | Swift |
let mut index=88; let r1=&mut index; let r2=&mut index; | let mut index=88; {{ let r1=&mut index; }} let r2=&mut index; | Only one mutable borrow. | Rust |
print('info') | print('info') | Correct. | R |
54index = 10 | index54 = 10 | Variable cannot start with digit. | Python |
{{'status':93, 'age' 46}} | {{'status':93, 'age':46}} | Colon missing. | Python |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
<user><age>test</age><desc>89</desc></user | <user><age>test</age><desc>89</desc></user> | Add closing >. | XML |
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