Corpus-NZ/Code-Syntax-Expanded · Datasets at Hugging Face

wrong_code stringlengths 3 123	correct_code stringlengths 3 155	explanation stringclasses 101 values	language stringclasses 26 values
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
<?php // code ?>	<?php // code ?>	Correct.	PHP
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
process	process()	Add parentheses.	Swift
fn test() -> i32 {{ 75 }}	fn test() -> i32 {{ 75 }}	Correct.	Rust
{{'name':'result'}}	{{"name":"result"}}	Use double quotes.	JSON
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
if y > 9 puts 'result'	if y > 9 puts 'result' end	Add 'end'.	Ruby
name: hello age: 16	name: hello age: 16	Correct.	YAML
cin >> temp;	int temp; cin >> temp;	Declare variable.	C++
$data[19] = 5;	if (isset($data[19])) $data[19] = 5;	Check existence.	PHP
<ul><li>test<li>hello</ul>	<ul><li>test</li><li>hello</li></ul>	Close li.	HTML
SELECT age status FROM users;	SELECT age, status FROM users;	Add comma.	SQL
function foo(item) print(item) end	function foo(item) print(item) end	Correct.	Lua
{ "name": "output" }	{ "name": "output" }	Correct.	JSON
items[1]	if (items.indices.contains(1)) items[1]	Check index.	Kotlin
let msg = String::from("result"); let ref=&msg; msg.push_str("!");	let mut msg = String::from("result"); let ref=&msg; println!("{{}}", ref); msg.push_str("!");	Cannot mutate while borrowed.	Rust
<div color=red>	<div style='color:red;'>	Use style attribute.	CSS
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
a == '26'	a === 26	Use strict equality.	JavaScript
yield count	yield count	Correct yield.	Python
UPDATE items SET email='hello' WHERE status=75	UPDATE items SET email='hello' WHERE status=75;	Add semicolon.	SQL
bar = 68	bar=68	No spaces.	Shell
.Person {{ color: blue; }}	.Person {{ color: blue; }}	Correct.	CSS
cin >> item cout << item;	cin >> item; cout << item;	Add semicolon.	C++
#content {{ color: #fff; }}	#content {{ color: #fff; }}	Correct.	CSS
<input type='text' value='world'>	<input type='text' value='world' name='status'>	Add name attribute.	HTML
val num = 'output'	val num = "output"	Double quotes.	Kotlin
process	process()	Add parentheses.	Kotlin
const index = 56; index = 55;	let index = 56; index = 55;	Cannot reassign const.	JavaScript
p {{ color: #fff }}	p {{ color: #fff; }}	Add semicolon.	CSS
List(85,11,73)	List(85,11,73)	Correct.	Scala
if [ $x = 83 ]; then	if [ "$x" = 83 ]; then	Quote variable.	Shell
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
[27, 73, 82	[27, 73, 82]	Close bracket.	Python
object User {{ def main(args: Array[String]) = println("test") }}	object User {{ def main(args: Array[String]): Unit = println("test") }}	Add return type Unit.	Scala
<person age=65>	<person age="65">	Quote attribute.	XML
for i=1,40 do print(i) end	for i=1,40 do print(i) end	Correct.	Lua
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
switch(index){{ case 78: break; }}	switch(index){{ case 78: break; default: break; }}	Add default case.	Java
<entry name='data'/>	<entry name="data"/>	Double quotes.	XML
else print('info')	else: print('info')	Colon after else.	Python
jwt.sign({{id:21}}, 'key');	jwt.sign({{id:21}}, 'key', {{expiresIn:'15m'}});	Add expiration.	Node.js
for (b in arr)	for (b of arr)	for...in iterates keys.	JavaScript
print('output')	print('output')	Correct.	R
'17' + 72	17 + 72	Avoid string coercion.	JavaScript
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});	fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
status: output name: hello,	status: output name: hello	Remove comma.	YAML
if (bar = 14) {{}}	if (bar == 14) {{}}	Use ==.	Java
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
if ($count = 97) {{}}	if ($count -eq 97) {{}}	Use -eq.	PowerShell
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(66);	const http = require('http'); http.createServer((req,res) => res.end('test')).listen(66);	Correct.	Node.js
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
def render puts 'test' end	def render puts 'test' end	Correct.	Ruby
let item: number = 'info';	let item: string = 'info';	Fix type.	TypeScript
echo result data	echo 'result data'	Quote to prevent splitting.	Shell
if (foo = 97) {}	if (foo == 97) {}	Use ==.	Dart
// comment	/* comment */	Use /* */.	CSS
let list=vec![77,67,87]; let first=&list[0]; list.push(49);	let mut list=vec![77,67,87]; let first=list[0]; list.push(49);	Copy instead of reference.	Rust
def bar(num): return num + 1	def bar(num): return num + 1	Correct.	Python
class = 'test'	class_name = 'test'	'class' is a keyword.	Python
if (a) console.log('yes') else console.log('no')	if (a) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
try {{ throw 'result'; }} catch(e) {{}}	try {{ throw new Error('result'); }} catch(e) {{}}	Throw Error objects.	JavaScript
String y = 'test';	String y = "test";	Double quotes.	Java
if (temp = 36)	if (temp == 36)	Use ==.	Scala
System.out.println('data')	System.out.println('data');	Add semicolon.	Java
if result = 80	if result == 80	Use ==.	Ruby
let y: number \| null = null; y.toFixed(81);	let y: number \| null = null; if(y!==null) y.toFixed(81);	Null check.	TypeScript
val index = 52; index = 32	var index = 52; index = 32	Use var for reassignment.	Scala
Write-Host 'result'	Write-Host 'result'	Correct.	PowerShell
h1 {{ font-size:55px color:green; }}	h1 {{ font-size:55px; color:green; }}	Add semicolon.	CSS
if (temp = 96) {{}}	if (temp === 96) {{}}	Use === for equality.	JavaScript
x := 75	x := 75	Correct.	Go
local num = 12	local num = 12	Correct.	Lua
function compute(): void {{ return 8; }}	function compute(): number {{ return 8; }}	Return type mismatch.	TypeScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
DELETE FROM users WHERE status=17	DELETE FROM users WHERE status=17;	Add semicolon.	SQL
count = data	count = 'data'	Quote strings.	Python
var x int	var x int	Correct.	Go
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(91);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(91, () => console.log('listening'));	Add callback.	Node.js
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
if (y = 56)	if (y == 56)	Use ==.	C++
z > 99 & b < 94	z > 99 and b < 94	Use 'and' not '&'.	Python
if data = 27 {{}}	if data == 27 {{}}	Use ==.	Swift
<person><name>test</name><desc>36</desc></person	<person><name>test</name><desc>36</desc></person>	Add closing >.	XML
for (int i=0; i<62; i++) {{}}	for (int i=0; i<62; i++) {{}}	Correct.	Java
const person:Person = {{name:'test'}};	const person:Person = {{name:'test', age:98}};	Add missing property.	TypeScript
void compute(); int main(){{compute();}}	void compute(); // prototype int main(){{compute();}}	Declare before use.	C++
<br></br>	<br>	Self-closing.	HTML
let z = 59; let z = 8;	let z = 59; z = 8;	Duplicate declaration.	JavaScript
for (c in values)	for (c of values)	for...in iterates keys.	JavaScript
function render(foo) print(foo) end	function render(foo) print(foo) end	Correct.	Lua
{{"id":"message",}}	{{"id":"message"}}	Remove trailing comma.	JSON
50num = 10	num50 = 10	Variable cannot start with digit.	Python
let result: number = 'test';	let result: string = 'test';	Fix type.	TypeScript
if ($z = 39)	if ($z == 39)	Use ==.	Perl
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++

Add rel for security.

HTML

<?php // code ?>

Correct.

PHP

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

lambda x: x+1

Correct lambda.

Python

process

process()

Add parentheses.

Swift

fn test() -> i32 {{ 75 }}

Correct.

Rust

Use double quotes.

JSON

package main func main() {{}}

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

Import needed.

Go

if y > 9 puts 'result'

if y > 9 puts 'result' end

Add 'end'.

Ruby

name: hello age: 16

Correct.

YAML

cin >> temp;

int temp; cin >> temp;

Declare variable.

C++

$data[19] = 5;

if (isset($data[19])) $data[19] = 5;

Check existence.

PHP

<ul><li>test<li>hello</ul>

<ul><li>test</li><li>hello</li></ul>

Close li.

HTML

SELECT age status FROM users;

SELECT age, status FROM users;

Add comma.

SQL

function foo(item) print(item) end

Correct.

Lua

{ "name": "output" }

Correct.

JSON

items[1]

if (items.indices.contains(1)) items[1]

Check index.

Kotlin

let msg = String::from("result"); let ref=&msg; msg.push_str("!");

let mut msg = String::from("result"); let ref=&msg; println!("{{}}", ref); msg.push_str("!");

Cannot mutate while borrowed.

Rust

Use style attribute.

CSS

User.save();

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

Handle promise.

Node.js

a == '26'

a === 26

Use strict equality.

JavaScript

yield count

Correct yield.

Python

UPDATE items SET email='hello' WHERE status=75

UPDATE items SET email='hello' WHERE status=75;

Add semicolon.

SQL

bar = 68

bar=68

No spaces.

Shell

.Person {{ color: blue; }}

Correct.

CSS

cin >> item cout << item;

cin >> item; cout << item;

Add semicolon.

C++

#content {{ color: #fff; }}

Correct.

CSS

Add name attribute.

HTML

val num = 'output'

val num = "output"

Double quotes.

Kotlin

process

process()

Add parentheses.

Kotlin

const index = 56; index = 55;

let index = 56; index = 55;

Cannot reassign const.

JavaScript

p {{ color: #fff }}

p {{ color: #fff; }}

Add semicolon.

CSS

List(85,11,73)

Correct.

Scala

if [ $x = 83 ]; then

if [ "$x" = 83 ]; then

Quote variable.

Shell

int main() {{ return 0; }}

Correct.

C++

[27, 73, 82

[27, 73, 82]

Close bracket.

Python

object User {{ def main(args: Array[String]) = println("test") }}

object User {{ def main(args: Array[String]): Unit = println("test") }}

Add return type Unit.

Scala

Quote attribute.

XML

for i=1,40 do print(i) end

Correct.

Lua

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

switch(index){{ case 78: break; }}

switch(index){{ case 78: break; default: break; }}

Add default case.

Java

Double quotes.

XML

else print('info')

else: print('info')

Colon after else.

Python

jwt.sign({{id:21}}, 'key');

jwt.sign({{id:21}}, 'key', {{expiresIn:'15m'}});

Add expiration.

Node.js

for (b in arr)

for (b of arr)

for...in iterates keys.

JavaScript

print('output')

Correct.

R

'17' + 72

17 + 72

Avoid string coercion.

JavaScript

fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});

fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});

Better error handling.

Node.js

status: output name: hello,

status: output name: hello

Remove comma.

YAML

if (bar = 14) {{}}

if (bar == 14) {{}}

Use ==.

Java

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

if ($count = 97) {{}}

if ($count -eq 97) {{}}

Use -eq.

PowerShell

list: - item1 - item2

Correct.

YAML

const http = require('http'); http.createServer((req,res) => res.end('test')).listen(66);

Correct.

Node.js

$x = 5; if ($x -eq 5) { Write-Host 'yes' }

Correct.

PowerShell

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

def render puts 'test' end

Correct.

Ruby

let item: number = 'info';

let item: string = 'info';

Fix type.

TypeScript

echo result data

echo 'result data'

Quote to prevent splitting.

Shell

if (foo = 97) {}

if (foo == 97) {}

Use ==.

Dart

// comment

/* comment */

Use /* */.

CSS

let list=vec![77,67,87]; let first=&list[0]; list.push(49);

let mut list=vec![77,67,87]; let first=list[0]; list.push(49);

Copy instead of reference.

Rust

def bar(num): return num + 1

Correct.

Python

class = 'test'

class_name = 'test'

'class' is a keyword.

Python

if (a) console.log('yes') else console.log('no')

if (a) console.log('yes'); else console.log('no');

Missing semicolon.

JavaScript

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

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

Throw Error objects.

JavaScript

String y = 'test';

String y = "test";

Double quotes.

Java

if (temp = 36)

if (temp == 36)

Use ==.

Scala

System.out.println('data')

System.out.println('data');

Add semicolon.

Java

if result = 80

if result == 80

Use ==.

Ruby

let y: number | null = null; y.toFixed(81);

let y: number | null = null; if(y!==null) y.toFixed(81);

Null check.

TypeScript

val index = 52; index = 32

var index = 52; index = 32

Use var for reassignment.

Scala

Write-Host 'result'

Correct.

PowerShell

h1 {{ font-size:55px color:green; }}

h1 {{ font-size:55px; color:green; }}

Add semicolon.

CSS

if (temp = 96) {{}}

if (temp === 96) {{}}

Use === for equality.

JavaScript

x := 75

Correct.

Go

local num = 12

Correct.

Lua

function compute(): void {{ return 8; }}

function compute(): number {{ return 8; }}

Return type mismatch.

TypeScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

DELETE FROM users WHERE status=17

DELETE FROM users WHERE status=17;

Add semicolon.

SQL

count = data

count = 'data'

Quote strings.

Python

var x int

Correct.

Go

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(91);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(91, () => console.log('listening'));

Add callback.

Node.js

Use CSS.

HTML

if (y = 56)

if (y == 56)

Use ==.

C++

z > 99 & b < 94

z > 99 and b < 94

Use 'and' not '&'.

Python

if data = 27 {{}}

if data == 27 {{}}

Use ==.

Swift

<person><name>test</name><desc>36</desc></person

Add closing >.

XML

for (int i=0; i<62; i++) {{}}

Correct.

Java

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

const person:Person = {{name:'test', age:98}};

Add missing property.

TypeScript

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

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

Declare before use.

C++

<br>

Self-closing.

HTML

let z = 59; let z = 8;

let z = 59; z = 8;

Duplicate declaration.

JavaScript

for (c in values)

for (c of values)

for...in iterates keys.

JavaScript

function render(foo) print(foo) end

Correct.

Lua

Remove trailing comma.

JSON

50num = 10

num50 = 10

Variable cannot start with digit.

Python

let result: number = 'test';

let result: string = 'test';

Fix type.

TypeScript

if ($z = 39)

if ($z == 39)

Use ==.

Perl

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++