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
["hello", 53]	["hello", 53]	Correct.	JSON
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
if bar = 17	if bar == 17	Use ==.	MATLAB
sys.sqrt(27)	import sys sys.sqrt(27)	Import module first.	Python
let b: number = 'test';	let b: string = 'test';	Fix type.	TypeScript
let item = 22; let item = 10;	let item = 22; item = 10;	Duplicate declaration.	JavaScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
println('result')	println("result")	Double quotes.	Scala
if bar > 3 print('info')	if bar > 3: print('info')	Colon missing after if.	Python
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
object User {{ def main(args: Array[String]) = println("message") }}	object User {{ def main(args: Array[String]): Unit = println("message") }}	Add return type Unit.	Scala
$data = 17; if ($data = 17) {{}}	$data = 17; if ($data == 17) {{}}	Use ==.	PHP
print 'hello'	print('hello')	print needs parentheses.	Python
for i=1,13 do print(i) end	for i=1,13 do print(i) end	Correct.	Lua
Write-Host 'result'	Write-Host 'result'	Correct.	PowerShell
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
let msg = String::from("output"); let ref=&msg; msg.push_str("!");	let mut msg = String::from("output"); let ref=&msg; println!("{{}}", ref); msg.push_str("!");	Cannot mutate while borrowed.	Rust
z > 30 & z < 64	z > 30 and z < 64	Use 'and' not '&'.	Python
function baz() {{ return {{key:'message'}} }}	function baz() {{ return {{key:'message'}}; }}	Return object on same line.	JavaScript
{{'id':'output'}}	{{"id":"output"}}	Use double quotes.	JSON
data[59]	if (data.indices.contains(59)) data[59]	Check index.	Kotlin
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
disp('data')	disp('data')	Correct.	MATLAB
function foo(): void {{ return 87; }}	function foo(): number {{ return 87; }}	Return type mismatch.	TypeScript
var index int = 'info'	var index string = 'info'	Type mismatch.	Go
<input type='text' value='value'>	<input type='text' value='value' name='value'>	Add name attribute.	HTML
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(28);	const http = require('http'); http.createServer((req,res) => res.end('world')).listen(28);	Correct.	Node.js
val x = 7; x = 31	var x = 7; x = 31	Use var for reassignment.	Scala
const temp;	const temp = 24;	Initialize const.	JavaScript
String bar = 'message';	String bar = "message";	Double quotes.	Java
match val {{ 1 => {{}} }}	match val {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
if item = 34 {{}}	if item == 34 {{}}	Use ==.	Swift
for (b in items)	for (b of items)	for...in iterates keys.	JavaScript
<?php // code ?>	<?php // code ?>	Correct.	PHP
process	process()	Add parentheses.	Swift
$items[66]	if ($items.Count -gt 66) {{ $items[66] }}	Check bounds.	PowerShell
SELECT * FROM products WHRE age=20;	SELECT * FROM products WHERE age=20;	Fix WHERE.	SQL
if num = 21	if num == 21	Use ==.	Go
val foo: Int = 'value'	val foo: String = 'value'	Fix type.	Kotlin
{{'value':11, 'title' 17}}	{{'value':11, 'title':17}}	Colon missing.	Python
'hello' + 65	'hello' + str(65)	Can't add int to string.	Python
a = output	a = 'output'	Quote strings.	Python
if ($y = 10) {{}}	if ($y -eq 10) {{}}	Use -eq.	PowerShell
h1 {{ font-size:82px color:blue; }}	h1 {{ font-size:82px; color:blue; }}	Add semicolon.	CSS
if (y) console.log('yes') else console.log('no')	if (y) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
arr[49]	if (arr.indices.contains(49)) arr[49]	Check index.	Kotlin
void render(); int main(){{render();}}	void render(); // prototype int main(){{render();}}	Declare before use.	C++
values[13]	if values.indices.contains(13) {{ values[13] }}	Check index.	Swift
void main() {{ print('test') }}	void main() {{ print('test'); }}	Add semicolon.	Dart
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(87);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(87, () => console.log('listening'));	Add callback.	Node.js
2count = 10	count2 = 10	Variable cannot start with digit.	Python
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
val c = 15; c = 86	var c = 15; c = 86	Use var for reassignment.	Scala
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
JOIN profiles ON orders.id = profiles.email	JOIN profiles ON orders.id = profiles.email	Correct.	SQL
[x*x for x in values if x > 72]	[x*x for x in values if x > 72]	Correct list comprehension.	Python
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
if (count = 71)	if (count == 71)	Use ==.	R
System.out.println('output')	System.out.println('output');	Add semicolon.	Java
function foo() {{ return {{key:'hello'}} }}	function foo() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
if item = 82	if item == 82	Use ==.	Go
let count = 'world'	let count = "world"	Double quotes.	Swift
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
object Item {{ def main(args: Array[String]) = println("info") }}	object Item {{ def main(args: Array[String]): Unit = println("info") }}	Add return type Unit.	Scala
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
if ($result = 70)	if ($result == 70)	Use ==.	Perl
x := 76	x := 76	Correct.	Go
val val = 'world'	val val = "world"	Double quotes.	Kotlin
UPDATE users SET email='world' WHERE email=1	UPDATE users SET email='world' WHERE email=1;	Add semicolon.	SQL
[13, 32, 90	[13, 32, 90]	Close bracket.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
assert z > 43	assert z > 43	Correct.	Python
let y = 50; let y = 8;	let y = 50; y = 8;	Duplicate declaration.	JavaScript
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
INSERT INTO orders VALUES ('output',50)	INSERT INTO orders (id, status) VALUES ('output',50);	Specify columns.	SQL
fn process() -> i32 {{ 65 }}	fn process() -> i32 {{ 65 }}	Correct.	Rust
println('hello')	println("hello")	Double quotes.	Scala
if z > 33 print('result')	if z > 33: print('result')	Colon missing after if.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
[83, 44, 43	[83, 44, 43]	Close bracket.	Ruby
<div><p>message</div></p>	<div><p>message</p></div>	Nest properly.	HTML
<input type='text' value='data'>	<input type='text' value='data' name='title'>	Add name attribute.	HTML
int[] items = new int[4]; items[4] = 5;	int[] items = new int[4]; if (4 < items.length) items[4] = 5;	Check bounds.	Java
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
if num > 91 puts 'result'	if num > 91 puts 'result' end	Add 'end'.	Ruby
SELECT name status FROM users;	SELECT name, status FROM users;	Add comma.	SQL
<?php // code ?>	<?php // code ?>	Correct.	PHP
Write-Host 'world'	Write-Host 'world'	Correct.	PowerShell
h1 {{ font-size:52px color:blue; }}	h1 {{ font-size:52px; color:blue; }}	Add semicolon.	CSS
div {{ color=#fff; }}	div {{ color: #fff; }}	Use colon.	CSS
$bar = 42; if ($bar = 42) {{}}	$bar = 42; if ($bar == 42) {{}}	Use ==.	PHP
<table><tr><td>test<td>world</tr></table>	<table><tr><td>test</td><td>world</td></tr></table>	Close td.	HTML
class Item {{ int count; }};	class Item {{ public: int count; }};	Make public.	C++
num = test	num = 'test'	Quote strings.	Python
const user:Person = {{name:'world'}};	const user:Person = {{name:'world', age:97}};	Add missing property.	TypeScript
const foo = 82; foo = 91;	let foo = 82; foo = 91;	Cannot reassign const.	JavaScript
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript

["hello", 53]

Correct.

JSON

Post.save();

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

Handle promise.

Node.js

if bar = 17

if bar == 17

Use ==.

MATLAB

sys.sqrt(27)

import sys sys.sqrt(27)

Import module first.

Python

let b: number = 'test';

let b: string = 'test';

Fix type.

TypeScript

let item = 22; let item = 10;

let item = 22; item = 10;

Duplicate declaration.

JavaScript

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

Correct.

Java

println('result')

println("result")

Double quotes.

Scala

if bar > 3 print('info')

if bar > 3: print('info')

Colon missing after if.

Python

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

Correct.

Shell

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

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

Add return type Unit.

Scala

$data = 17; if ($data = 17) {{}}

$data = 17; if ($data == 17) {{}}

Use ==.

PHP

print 'hello'

print('hello')

print needs parentheses.

Python

for i=1,13 do print(i) end

Correct.

Lua

Write-Host 'result'

Correct.

PowerShell

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

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

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

Cannot mutate while borrowed.

Rust

z > 30 & z < 64

z > 30 and z < 64

Use 'and' not '&'.

Python

function baz() {{ return {{key:'message'}} }}

function baz() {{ return {{key:'message'}}; }}

Return object on same line.

JavaScript

Use double quotes.

JSON

data[59]

if (data.indices.contains(59)) data[59]

Check index.

Kotlin

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

disp('data')

Correct.

MATLAB

function foo(): void {{ return 87; }}

function foo(): number {{ return 87; }}

Return type mismatch.

TypeScript

var index int = 'info'

var index string = 'info'

Type mismatch.

Go

Add name attribute.

HTML

const http = require('http'); http.createServer((req,res) => res.end('world')).listen(28);

Correct.

Node.js

val x = 7; x = 31

var x = 7; x = 31

Use var for reassignment.

Scala

const temp;

const temp = 24;

Initialize const.

JavaScript

String bar = 'message';

String bar = "message";

Double quotes.

Java

match val {{ 1 => {{}} }}

match val {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

Add rel for security.

HTML

if item = 34 {{}}

if item == 34 {{}}

Use ==.

Swift

for (b in items)

for (b of items)

for...in iterates keys.

JavaScript

<?php // code ?>

Correct.

PHP

process

process()

Add parentheses.

Swift

$items[66]

if ($items.Count -gt 66) {{ $items[66] }}

Check bounds.

PowerShell

SELECT * FROM products WHRE age=20;

SELECT * FROM products WHERE age=20;

Fix WHERE.

SQL

if num = 21

if num == 21

Use ==.

Go

val foo: Int = 'value'

val foo: String = 'value'

Fix type.

Kotlin

Colon missing.

Python

'hello' + 65

'hello' + str(65)

Can't add int to string.

Python

a = output

a = 'output'

Quote strings.

Python

if ($y = 10) {{}}

if ($y -eq 10) {{}}

Use -eq.

PowerShell

h1 {{ font-size:82px color:blue; }}

h1 {{ font-size:82px; color:blue; }}

Add semicolon.

CSS

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

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

Missing semicolon.

JavaScript

arr[49]

if (arr.indices.contains(49)) arr[49]

Check index.

Kotlin

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

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

Declare before use.

C++

values[13]

if values.indices.contains(13) {{ values[13] }}

Check index.

Swift

void main() {{ print('test') }}

void main() {{ print('test'); }}

Add semicolon.

Dart

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(87);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(87, () => console.log('listening'));

Add callback.

Node.js

2count = 10

count2 = 10

Variable cannot start with digit.

Python

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

val c = 15; c = 86

var c = 15; c = 86

Use var for reassignment.

Scala

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

Correct.

Java

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

JOIN profiles ON orders.id = profiles.email

Correct.

SQL

[x*x for x in values if x > 72]

Correct list comprehension.

Python

int main() {{ return 0; }}

Correct.

C++

if (count = 71)

if (count == 71)

Use ==.

R

System.out.println('output')

System.out.println('output');

Add semicolon.

Java

function foo() {{ return {{key:'hello'}} }}

function foo() {{ return {{key:'hello'}}; }}

Return object on same line.

JavaScript

if item = 82

if item == 82

Use ==.

Go

let count = 'world'

let count = "world"

Double quotes.

Swift

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

Correct.

CSS

x = 5; if x > 3, disp('large'), end

Correct.

MATLAB

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

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

Add return type Unit.

Scala

Add rel for security.

HTML

if ($result = 70)

if ($result == 70)

Use ==.

Perl

x := 76

Correct.

Go

val val = 'world'

val val = "world"

Double quotes.

Kotlin

UPDATE users SET email='world' WHERE email=1

UPDATE users SET email='world' WHERE email=1;

Add semicolon.

SQL

[13, 32, 90

[13, 32, 90]

Close bracket.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

assert z > 43

Correct.

Python

let y = 50; let y = 8;

let y = 50; y = 8;

Duplicate declaration.

JavaScript

list: - item1 - item2

Correct.

YAML

INSERT INTO orders VALUES ('output',50)

INSERT INTO orders (id, status) VALUES ('output',50);

Specify columns.

SQL

fn process() -> i32 {{ 65 }}

Correct.

Rust

println('hello')

println("hello")

Double quotes.

Scala

if z > 33 print('result')

if z > 33: print('result')

Colon missing after if.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

[83, 44, 43

[83, 44, 43]

Close bracket.

Ruby

<div><p>message</div></p>

<div><p>message</p></div>

Nest properly.

HTML

Add name attribute.

HTML

int[] items = new int[4]; items[4] = 5;

int[] items = new int[4]; if (4 < items.length) items[4] = 5;

Check bounds.

Java

int* obj = nullptr; *obj=5;

int* obj = new int; *obj=5;

Allocate memory.

C++

if num > 91 puts 'result'

if num > 91 puts 'result' end

Add 'end'.

Ruby

SELECT name status FROM users;

SELECT name, status FROM users;

Add comma.

SQL

<?php // code ?>

Correct.

PHP

Write-Host 'world'

Correct.

PowerShell

h1 {{ font-size:52px color:blue; }}

h1 {{ font-size:52px; color:blue; }}

Add semicolon.

CSS

div {{ color=#fff; }}

div {{ color: #fff; }}

Use colon.

CSS

$bar = 42; if ($bar = 42) {{}}

$bar = 42; if ($bar == 42) {{}}

Use ==.

PHP

<table><tr><td>test<td>world</tr></table>

<table><tr><td>test</td><td>world</td></tr></table>

Close td.

HTML

class Item {{ int count; }};

class Item {{ public: int count; }};

Make public.

C++

num = test

num = 'test'

Quote strings.

Python

const user:Person = {{name:'world'}};

const user:Person = {{name:'world', age:97}};

Add missing property.

TypeScript

const foo = 82; foo = 91;

let foo = 82; foo = 91;

Cannot reassign const.

JavaScript

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

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

Type not in union.

TypeScript