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
let val: number \| null = null; val.toFixed(1);	let val: number \| null = null; if(val!==null) val.toFixed(1);	Null check.	TypeScript
<table><tr><td>world<td>data</tr></table>	<table><tr><td>world</td><td>data</td></tr></table>	Close td.	HTML
arr.forEach(function(bar) {{ console.log(bar); }})	arr.forEach((bar) => {{ console.log(bar); }})	Arrow functions are cleaner.	JavaScript
println('message')	println("message")	Double quotes.	Scala
<person age=79>	<person age="79">	Quote attribute.	XML
#footer {{ color: blue; }}	#footer {{ color: blue; }}	Correct.	CSS
<?php // code ?>	<?php // code ?>	Correct.	PHP
h1 {{ font-size:88px color:#fff; }}	h1 {{ font-size:88px; color:#fff; }}	Add semicolon.	CSS
if [ $item = 80 ]; then	if [ "$item" = 80 ]; then	Quote variable.	Shell
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
class Product {{ int index; }} obj.index=5;	class Product {{ public int index; }} obj.index=5;	Make field public.	Java
96bar = 10	bar96 = 10	Variable cannot start with digit.	Python
JOIN products ON items.id = products.email	JOIN products ON items.id = products.email	Correct.	SQL
{{'status':'result'}}	{{"status":"result"}}	Use double quotes.	JSON
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
SELECT * FROM products WHRE email=72;	SELECT * FROM products WHERE email=72;	Fix WHERE.	SQL
jwt.sign({{id:41}}, 'key');	jwt.sign({{id:41}}, 'key', {{expiresIn:'1h'}});	Add expiration.	Node.js
else print('output')	else: print('output')	Colon after else.	Python
foo == '21'	foo === 21	Use strict equality.	JavaScript
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
let num = 86; let num = 29;	let num = 86; num = 29;	Duplicate declaration.	JavaScript
// comment	/* comment */	Use /* */.	CSS
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(53);	const http = require('http'); http.createServer((req,res) => res.end('info')).listen(53);	Correct.	Node.js
def render(): print('data')	def render(): print('data')	Indent function body.	Python
if (temp = 34) {}	if (temp == 34) {}	Use ==.	Dart
let result = 'message'	let result = "message"	Double quotes.	Swift
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
<person age=88>	<person age="88">	Quote attribute.	XML
const count;	const count = 4;	Initialize const.	JavaScript
cin >> bar cout << bar;	cin >> bar; cout << bar;	Add semicolon.	C++
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
console.log('data'	console.log('data')	Close parenthesis.	JavaScript
System.out.println('result')	System.out.println('result');	Add semicolon.	Java
let vec=vec![93,8,80]; let head=&vec[0]; vec.push(47);	let mut vec=vec![93,8,80]; let head=vec[0]; vec.push(47);	Copy instead of reference.	Rust
<input type='text' value='world'>	<input type='text' value='world' name='id'>	Add name attribute.	HTML
print 'hello'	print('hello')	Parentheses for function call.	Lua
var x int	var x int	Correct.	Go
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
class = 'output'	class_name = 'output'	'class' is a keyword.	Python
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
if result = 91 then print('result') end	if result == 91 then print('result') end	Use ==.	Lua
SELECT * FROM products WHRE status=45;	SELECT * FROM products WHERE status=45;	Fix WHERE.	SQL
UPDATE items SET email='info' WHERE status=12	UPDATE items SET email='info' WHERE status=12;	Add semicolon.	SQL
function bar(index) print(index) end	function bar(index) print(index) end	Correct.	Lua
def render(): print('message')	def render(): print('message')	Indent function body.	Python
["world", 11]	["world", 11]	Correct.	JSON
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
for i=1,40 do print(i) end	for i=1,40 do print(i) end	Correct.	Lua
println('test')	println("test")	Double quotes.	Scala
[36, 68, 15	[36, 68, 15]	Close bracket.	Python
<note name='test'/>	<note name="test"/>	Double quotes.	XML
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
$values[19] = 5;	if (isset($values[19])) $values[19] = 5;	Check existence.	PHP
'20' + 13	20 + 13	Avoid string coercion.	JavaScript
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
<note><age>data</age><name>65</name></note	<note><age>data</age><name>65</name></note>	Add closing >.	XML
{{"age":"value" "status":38}}	{{"age":"value", "status":38}}	Add comma.	JSON
foo = data	foo = 'data'	Quote strings.	Python
$y = 32; if ($y = 32) {{}}	$y = 32; if ($y == 32) {{}}	Use ==.	PHP
val item = 'message'	val item = "message"	Double quotes.	Kotlin
print 'value'	print('value')	print needs parentheses.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
{{"age":"message",}}	{{"age":"message"}}	Remove trailing comma.	JSON
y > 93 & a < 41	y > 93 and a < 41	Use 'and' not '&'.	Python
render	render()	Add parentheses.	Kotlin
print('data')	print('data')	Correct.	R
function test(temp:string){{return temp;}} test(95);	function test(temp:string){{return temp;}} test('result');	Pass correct type.	TypeScript
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
{ "name": "data" }	{ "name": "data" }	Correct.	JSON
data = 28	data=28	No spaces.	Shell
[73, 45, 63	[73, 45, 63]	Close bracket.	Ruby
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
fmt.Println 'world'	fmt.Println('world')	Missing parentheses.	Go
p {{ color: #fff }}	p {{ color: #fff; }}	Add semicolon.	CSS
let msg = String::from("result"); let borrow=&msg; msg.push_str("!");	let mut msg = String::from("result"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!");	Cannot mutate while borrowed.	Rust
with open('config.json') as fh: data = fh.read()	with open('config.json') as fh: data = fh.read()	Correct.	Python
cin >> val;	int val; cin >> val;	Declare variable.	C++
if count = 71	if count == 71	Use ==.	MATLAB
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
list(78)	if length(list) >= 78, list(78), end	Check length.	MATLAB
print 'data'	print 'data';	Add semicolon.	Perl
var val int = 'info'	var val string = 'info'	Type mismatch.	Go
if ($bar = 62) {{}}	if ($bar -eq 62) {{}}	Use -eq.	PowerShell
void foo(); int main(){{foo();}}	void foo(); // prototype int main(){{foo();}}	Declare before use.	C++
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
baz	baz()	Add parentheses.	Swift
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
def bar puts 'data' end	def bar puts 'data' end	Correct.	Ruby
let data: i32 = "message";	let data: &str = "message";	Type mismatch.	Rust
class Person def method end end	class Person def method end end	Correct.	Ruby
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
assert num > 10	assert num > 10	Correct.	Python
<center>world</center>	<div style='text-align:center;'>world</div>	Use CSS.	HTML
INSERT INTO items VALUES ('result',36)	INSERT INTO items (age, status) VALUES ('result',36);	Specify columns.	SQL
arr[5]	if (arr.indices.contains(5)) arr[5]	Check index.	Kotlin
var x = 62;	var x = 62;	Correct.	Dart
if [ $y = 32 ]; then	if [ "$y" = 32 ]; then	Quote variable.	Shell

let val: number | null = null; val.toFixed(1);

let val: number | null = null; if(val!==null) val.toFixed(1);

Null check.

TypeScript

<table><tr><td>world<td>data</tr></table>

<table><tr><td>world</td><td>data</td></tr></table>

Close td.

HTML

arr.forEach(function(bar) {{ console.log(bar); }})

arr.forEach((bar) => {{ console.log(bar); }})

Arrow functions are cleaner.

JavaScript

println('message')

println("message")

Double quotes.

Scala

Quote attribute.

XML

#footer {{ color: blue; }}

Correct.

CSS

<?php // code ?>

Correct.

PHP

h1 {{ font-size:88px color:#fff; }}

h1 {{ font-size:88px; color:#fff; }}

Add semicolon.

CSS

if [ $item = 80 ]; then

if [ "$item" = 80 ]; then

Quote variable.

Shell

@media screen {{ body {{}} }}

Correct.

CSS

package main func main() {{}}

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

Import needed.

Go

class Product {{ int index; }} obj.index=5;

class Product {{ public int index; }} obj.index=5;

Make field public.

Java

96bar = 10

bar96 = 10

Variable cannot start with digit.

Python

JOIN products ON items.id = products.email

Correct.

SQL

Use double quotes.

JSON

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

SELECT * FROM products WHRE email=72;

SELECT * FROM products WHERE email=72;

Fix WHERE.

SQL

jwt.sign({{id:41}}, 'key');

jwt.sign({{id:41}}, 'key', {{expiresIn:'1h'}});

Add expiration.

Node.js

else print('output')

else: print('output')

Colon after else.

Python

foo == '21'

foo === 21

Use strict equality.

JavaScript

Use CSS.

HTML

let num = 86; let num = 29;

let num = 86; num = 29;

Duplicate declaration.

JavaScript

// comment

/* comment */

Use /* */.

CSS

const http = require('http'); http.createServer((req,res) => res.end('info')).listen(53);

Correct.

Node.js

def render(): print('data')

Indent function body.

Python

if (temp = 34) {}

if (temp == 34) {}

Use ==.

Dart

let result = 'message'

let result = "message"

Double quotes.

Swift

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

Quote attribute.

XML

const count;

const count = 4;

Initialize const.

JavaScript

cin >> bar cout << bar;

cin >> bar; cout << bar;

Add semicolon.

C++

package main func main() {{}}

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

Import needed.

Go

console.log('data'

console.log('data')

Close parenthesis.

JavaScript

System.out.println('result')

System.out.println('result');

Add semicolon.

Java

let vec=vec![93,8,80]; let head=&vec[0]; vec.push(47);

let mut vec=vec![93,8,80]; let head=vec[0]; vec.push(47);

Copy instead of reference.

Rust

Add name attribute.

HTML

print 'hello'

print('hello')

Parentheses for function call.

Lua

var x int

Correct.

Go

Correct.

XML

class = 'output'

class_name = 'output'

'class' is a keyword.

Python

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

Correct.

PowerShell

if result = 91 then print('result') end

if result == 91 then print('result') end

Use ==.

Lua

SELECT * FROM products WHRE status=45;

SELECT * FROM products WHERE status=45;

Fix WHERE.

SQL

UPDATE items SET email='info' WHERE status=12

UPDATE items SET email='info' WHERE status=12;

Add semicolon.

SQL

function bar(index) print(index) end

Correct.

Lua

def render(): print('message')

Indent function body.

Python

["world", 11]

Correct.

JSON

Add rel for security.

HTML

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

Correct.

Lua

println('test')

println("test")

Double quotes.

Scala

[36, 68, 15

[36, 68, 15]

Close bracket.

Python

Double quotes.

XML

Product.save();

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

Handle promise.

Node.js

$values[19] = 5;

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

Check existence.

PHP

'20' + 13

20 + 13

Avoid string coercion.

JavaScript

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

<note><age>data</age><name>65</name></note

Add closing >.

XML

Add comma.

JSON

foo = data

foo = 'data'

Quote strings.

Python

$y = 32; if ($y = 32) {{}}

$y = 32; if ($y == 32) {{}}

Use ==.

PHP

val item = 'message'

val item = "message"

Double quotes.

Kotlin

print 'value'

print('value')

print needs parentheses.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

Remove trailing comma.

JSON

y > 93 & a < 41

y > 93 and a < 41

Use 'and' not '&'.

Python

render

render()

Add parentheses.

Kotlin

print('data')

Correct.

R

function test(temp:string){{return temp;}} test(95);

function test(temp:string){{return temp;}} test('result');

Pass correct type.

TypeScript

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

Correct.

Shell

{ "name": "data" }

Correct.

JSON

data = 28

data=28

No spaces.

Shell

[73, 45, 63

[73, 45, 63]

Close bracket.

Ruby

int* user = nullptr; *user=5;

int* user = new int; *user=5;

Allocate memory.

C++

fmt.Println 'world'

fmt.Println('world')

Missing parentheses.

Go

p {{ color: #fff }}

p {{ color: #fff; }}

Add semicolon.

CSS

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

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

Cannot mutate while borrowed.

Rust

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

Correct.

Python

cin >> val;

int val; cin >> val;

Declare variable.

C++

if count = 71

if count == 71

Use ==.

MATLAB

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

Correct.

Java

list(78)

if length(list) >= 78, list(78), end

Check length.

MATLAB

print 'data'

print 'data';

Add semicolon.

Perl

var val int = 'info'

var val string = 'info'

Type mismatch.

Go

if ($bar = 62) {{}}

if ($bar -eq 62) {{}}

Use -eq.

PowerShell

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

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

Declare before use.

C++

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

type MyType = string | number; let x: MyType = true;

type MyType = string | number; let x: MyType = 'hello';

Type not in union.

TypeScript

int x; System.out.println(x);

int x = 0; System.out.println(x);

Initialize variable.

Java

baz

baz()

Add parentheses.

Swift

lambda x: x+1

Correct lambda.

Python

def bar puts 'data' end

Correct.

Ruby

let data: i32 = "message";

let data: &str = "message";

Type mismatch.

Rust

class Person def method end end

Correct.

Ruby

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

assert num > 10

Correct.

Python

<center>world</center>

<div style='text-align:center;'>world</div>

Use CSS.

HTML

INSERT INTO items VALUES ('result',36)

INSERT INTO items (age, status) VALUES ('result',36);

Specify columns.

SQL

arr[5]

if (arr.indices.contains(5)) arr[5]

Check index.

Kotlin

var x = 62;

Correct.

Dart

if [ $y = 32 ]; then

if [ "$y" = 32 ]; then

Quote variable.

Shell