Gugu8/Code-Syntax · Datasets at Hugging Face

wrong_code stringlengths 3 123	correct_code stringlengths 3 155	explanation stringclasses 83 values	language stringclasses 23 values
if (result = 46) {{}}	if (result == 46) {{}}	Use ==.	Kotlin
let x = 82;	let x = 82;	Correct.	JavaScript
h1 {{ font-size:66px color:green; }}	h1 {{ font-size:66px; color:green; }}	Add semicolon.	CSS
fmt.Println 'value'	fmt.Println('value')	Missing parentheses.	Go
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
x := 86	x := 86	Correct.	Go
assert a > 22	assert a > 22	Correct.	Python
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(43);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(43, () => console.log('listening'));	Add callback.	Node.js
String foo = 'data';	String foo = "data";	Double quotes.	Java
items(49)	if length(items) >= 49, items(49), end	Check length.	MATLAB
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
<br></br>	<br>	Self-closing.	HTML
<note><name>test</name><name>86</name></note	<note><name>test</name><name>86</name></note>	Add closing >.	XML
if result = 29	if result == 29	Use ==.	Ruby
DELETE FROM orders WHERE email=42	DELETE FROM orders WHERE email=42;	Add semicolon.	SQL
a > 42 & z < 23	a > 42 and z < 23	Use 'and' not '&'.	Python
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
const item;	const item = 18;	Initialize const.	JavaScript
if ($bar = 1) {{}}	if ($bar -eq 1) {{}}	Use -eq.	PowerShell
var result int = 'message'	var result string = 'message'	Type mismatch.	Go
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
re.sqrt(77)	import re re.sqrt(77)	Import module first.	Python
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
<person name='message'/>	<person name="message"/>	Double quotes.	XML
["value", 78]	["value", 78]	Correct.	JSON
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
def compute puts 'hello' end	def compute puts 'hello' end	Correct.	Ruby
data = 65	data=65	No spaces.	Shell
for (int i=0; i<19; i++) {{}}	for (int i=0; i<19; i++) {{}}	Correct.	Java
echo 'hello'	echo 'hello';	Add semicolon.	PHP
'output' + 78	'output' + str(78)	Can't add int to string.	Python
<p>data <b>test</p></b>	<p>data <b>test</b></p>	Nest properly.	HTML
let a = 'value'	let a = "value"	Double quotes.	Swift
let mut data=48; let ref1=&mut data; let ref2=&mut data;	let mut data=48; {{ let ref1=&mut data; }} let ref2=&mut data;	Only one mutable borrow.	Rust
function bar() {{ return {{key:'data'}} }}	function bar() {{ return {{key:'data'}}; }}	Return object on same line.	JavaScript
print 'world'	print 'world';	Add semicolon.	Perl
53x = 10	x53 = 10	Variable cannot start with digit.	Python
jwt.sign({{id:50}}, 'token');	jwt.sign({{id:50}}, 'token', {{expiresIn:'15m'}});	Add expiration.	Node.js
let temp: number \| null = null; temp.toFixed(54);	let temp: number \| null = null; if(temp!==null) temp.toFixed(54);	Null check.	TypeScript
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
cin >> x cout << x;	cin >> x; cout << x;	Add semicolon.	C++
if (y = 98) {{}}	if (y === 98) {{}}	Use === for equality.	JavaScript
if val > 24 puts 'message'	if val > 24 puts 'message' end	Add 'end'.	Ruby
try {{ throw 'data'; }} catch(e) {{}}	try {{ throw new Error('data'); }} catch(e) {{}}	Throw Error objects.	JavaScript
// comment	/* comment */	Use /* */.	CSS
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
val index: Int = 'world'	val index: String = 'world'	Fix type.	Kotlin
def test(): print('test')	def test(): print('test')	Indent function body.	Python
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
$data[14] = 5;	if (isset($data[14])) $data[14] = 5;	Check existence.	PHP
[50, 26, 93	[50, 26, 93]	Close bracket.	Python
if num = 5 {{}}	if num == 5 {{}}	Use ==.	Swift
{{'title':'test'}}	{{"title":"test"}}	Use double quotes.	JSON
bar = world	bar = 'world'	Quote strings.	Python
for (foo in values)	for (foo of values)	for...in iterates keys.	JavaScript
if ($z = 80)	if ($z == 80)	Use ==.	Perl
<img src='test.jpg'>	<img src='test.jpg' alt='desc'>	Add alt text.	HTML
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
items[85]	if items.indices.contains(85) {{ items[85] }}	Check index.	Swift
'value' + 44	'value' + 44.to_s	Convert int.	Ruby
class User {{ int temp; }} obj.temp=5;	class User {{ public int temp; }} obj.temp=5;	Make field public.	Java
function compute(result:string){{return result;}} compute(72);	function compute(result:string){{return result;}} compute('value');	Pass correct type.	TypeScript
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(11);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(11, () => console.log('listening'));	Add callback.	Node.js
$items[56] = 5;	if (isset($items[56])) $items[56] = 5;	Check existence.	PHP
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
count = value	count = 'value'	Quote strings.	Python
let list=vec![29,54,38]; let primary=&list[0]; list.push(21);	let mut list=vec![29,54,38]; let primary=list[0]; list.push(21);	Copy instead of reference.	Rust
<br></br>	<br>	Self-closing.	HTML
process	process()	Add parentheses.	Swift
// comment	/* comment */	Use /* */.	CSS
let text1 = String::from("output"); let str2 = text1; println!("{{}}", text1);	let text1 = String::from("output"); let str2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
let val: i32 = "value";	let val: &str = "value";	Type mismatch.	Rust
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
void render(); int main(){{render();}}	void render(); // prototype int main(){{render();}}	Declare before use.	C++
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
with open('config.json') as f: data = f.read()	with open('config.json') as f: data = f.read()	Correct.	Python
echo message test	echo 'message test'	Quote to prevent splitting.	Shell
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
SELECT * FROM products WHRE email=38;	SELECT * FROM products WHERE email=38;	Fix WHERE.	SQL
<note name='test'/>	<note name="test"/>	Double quotes.	XML
print 'test'	print('test')	print needs parentheses.	Python
val data = 'message'	val data = "message"	Double quotes.	Kotlin
["test", 85]	["test", 85]	Correct.	JSON
$list[85]	if ($list.Count -gt 85) {{ $list[85] }}	Check bounds.	PowerShell
let mut count=63; let r1=&mut count; let ref2=&mut count;	let mut count=63; {{ let r1=&mut count; }} let ref2=&mut count;	Only one mutable borrow.	Rust
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
<hr></hr>	<hr>	Self-closing.	HTML
x := 19	x := 19	Correct.	Go
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if result > 38 print('value')	if result > 38: print('value')	Colon missing after if.	Python
match b {{ 1 => {{}} }}	match b {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
values.forEach(function(b) {{ console.log(b); }})	values.forEach((b) => {{ console.log(b); }})	Arrow functions are cleaner.	JavaScript
$index = 79; if ($index = 79) {{}}	$index = 79; if ($index == 79) {{}}	Use ==.	PHP
function test() {{ return {{key:'info'}} }}	function test() {{ return {{key:'info'}}; }}	Return object on same line.	JavaScript
const obj:Person = {{name:'test'}};	const obj:Person = {{name:'test', age:96}};	Add missing property.	TypeScript
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
foo	foo()	Add parentheses.	Kotlin
if [ $data = 37 ]; then	if [ "$data" = 37 ]; then	Quote variable.	Shell

if (result = 46) {{}}

if (result == 46) {{}}

Use ==.

Kotlin

let x = 82;

Correct.

JavaScript

h1 {{ font-size:66px color:green; }}

h1 {{ font-size:66px; color:green; }}

Add semicolon.

CSS

fmt.Println 'value'

fmt.Println('value')

Missing parentheses.

Go

ArrayList list = new ArrayList();

ArrayList<String> list = new ArrayList<>();

Use generics.

Java

x := 86

Correct.

Go

assert a > 22

Correct.

Python

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(43);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(43, () => console.log('listening'));

Add callback.

Node.js

String foo = 'data';

String foo = "data";

Double quotes.

Java

items(49)

if length(items) >= 49, items(49), end

Check length.

MATLAB

for i in $(ls); do echo $i; done

Correct.

Shell

<br>

Self-closing.

HTML

<note><name>test</name><name>86</name></note

Add closing >.

XML

if result = 29

if result == 29

Use ==.

Ruby

DELETE FROM orders WHERE email=42

DELETE FROM orders WHERE email=42;

Add semicolon.

SQL

a > 42 & z < 23

a > 42 and z < 23

Use 'and' not '&'.

Python

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

const item;

const item = 18;

Initialize const.

JavaScript

if ($bar = 1) {{}}

if ($bar -eq 1) {{}}

Use -eq.

PowerShell

var result int = 'message'

var result string = 'message'

Type mismatch.

Go

Write-Host 'info'

Correct.

PowerShell

re.sqrt(77)

import re re.sqrt(77)

Import module first.

Python

match c {{ 1 => {{}} }}

match c {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

Double quotes.

XML

["value", 78]

Correct.

JSON

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

def compute puts 'hello' end

Correct.

Ruby

data = 65

data=65

No spaces.

Shell

for (int i=0; i<19; i++) {{}}

Correct.

Java

echo 'hello'

echo 'hello';

Add semicolon.

PHP

'output' + 78

'output' + str(78)

Can't add int to string.

Python

Nest properly.

HTML

let a = 'value'

let a = "value"

Double quotes.

Swift

let mut data=48; let ref1=&mut data; let ref2=&mut data;

let mut data=48; {{ let ref1=&mut data; }} let ref2=&mut data;

Only one mutable borrow.

Rust

function bar() {{ return {{key:'data'}} }}

function bar() {{ return {{key:'data'}}; }}

Return object on same line.

JavaScript

print 'world'

print 'world';

Add semicolon.

Perl

53x = 10

x53 = 10

Variable cannot start with digit.

Python

jwt.sign({{id:50}}, 'token');

jwt.sign({{id:50}}, 'token', {{expiresIn:'15m'}});

Add expiration.

Node.js

let temp: number | null = null; temp.toFixed(54);

let temp: number | null = null; if(temp!==null) temp.toFixed(54);

Null check.

TypeScript

package main func main() {{}}

package main import 'fmt' func main() {{}}

Import needed.

Go

cin >> x cout << x;

cin >> x; cout << x;

Add semicolon.

C++

if (y = 98) {{}}

if (y === 98) {{}}

Use === for equality.

JavaScript

if val > 24 puts 'message'

if val > 24 puts 'message' end

Add 'end'.

Ruby

try {{ throw 'data'; }} catch(e) {{}}

try {{ throw new Error('data'); }} catch(e) {{}}

Throw Error objects.

JavaScript

// comment

/* comment */

Use /* */.

CSS

Correct.

XML

val index: Int = 'world'

val index: String = 'world'

Fix type.

Kotlin

def test(): print('test')

Indent function body.

Python

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

$data[14] = 5;

if (isset($data[14])) $data[14] = 5;

Check existence.

PHP

[50, 26, 93

[50, 26, 93]

Close bracket.

Python

if num = 5 {{}}

if num == 5 {{}}

Use ==.

Swift

Use double quotes.

JSON

bar = world

bar = 'world'

Quote strings.

Python

for (foo in values)

for (foo of values)

for...in iterates keys.

JavaScript

if ($z = 80)

if ($z == 80)

Use ==.

Perl

Add alt text.

HTML

int main() {{ return 0; }}

Correct.

C++

items[85]

if items.indices.contains(85) {{ items[85] }}

Check index.

Swift

'value' + 44

'value' + 44.to_s

Convert int.

Ruby

class User {{ int temp; }} obj.temp=5;

class User {{ public int temp; }} obj.temp=5;

Make field public.

Java

function compute(result:string){{return result;}} compute(72);

function compute(result:string){{return result;}} compute('value');

Pass correct type.

TypeScript

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(11);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(11, () => console.log('listening'));

Add callback.

Node.js

$items[56] = 5;

if (isset($items[56])) $items[56] = 5;

Check existence.

PHP

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

count = value

count = 'value'

Quote strings.

Python

let list=vec![29,54,38]; let primary=&list[0]; list.push(21);

let mut list=vec![29,54,38]; let primary=list[0]; list.push(21);

Copy instead of reference.

Rust

<br>

Self-closing.

HTML

process

process()

Add parentheses.

Swift

// comment

/* comment */

Use /* */.

CSS

let text1 = String::from("output"); let str2 = text1; println!("{{}}", text1);

let text1 = String::from("output"); let str2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

let val: i32 = "value";

let val: &str = "value";

Type mismatch.

Rust

User.save();

User.save().then(()=>{{}}).catch(err=>{{}});

Handle promise.

Node.js

void render(); int main(){{render();}}

void render(); // prototype int main(){{render();}}

Declare before use.

C++

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

with open('config.json') as f: data = f.read()

Correct.

Python

echo message test

echo 'message test'

Quote to prevent splitting.

Shell

Correct.

XML

SELECT * FROM products WHRE email=38;

SELECT * FROM products WHERE email=38;

Fix WHERE.

SQL

Double quotes.

XML

print 'test'

print('test')

print needs parentheses.

Python

val data = 'message'

val data = "message"

Double quotes.

Kotlin

["test", 85]

Correct.

JSON

$list[85]

if ($list.Count -gt 85) {{ $list[85] }}

Check bounds.

PowerShell

let mut count=63; let r1=&mut count; let ref2=&mut count;

let mut count=63; {{ let r1=&mut count; }} let ref2=&mut count;

Only one mutable borrow.

Rust

<table><tr><td>data<td>hello</tr></table>

<table><tr><td>data</td><td>hello</td></tr></table>

Close td.

HTML

<hr>

Self-closing.

HTML

x := 19

Correct.

Go

public static void main(String[] args) {{}}

Correct.

Java

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if result > 38 print('value')

if result > 38: print('value')

Colon missing after if.

Python

match b {{ 1 => {{}} }}

match b {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

values.forEach(function(b) {{ console.log(b); }})

values.forEach((b) => {{ console.log(b); }})

Arrow functions are cleaner.

JavaScript

$index = 79; if ($index = 79) {{}}

$index = 79; if ($index == 79) {{}}

Use ==.

PHP

function test() {{ return {{key:'info'}} }}

function test() {{ return {{key:'info'}}; }}

Return object on same line.

JavaScript

const obj:Person = {{name:'test'}};

const obj:Person = {{name:'test', age:96}};

Add missing property.

TypeScript

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

Add rel for security.

HTML

foo

foo()

Add parentheses.

Kotlin

if [ $data = 37 ]; then

if [ "$data" = 37 ]; then

Quote variable.

Shell