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
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
handle	handle()	Add parentheses.	Swift
var x int	var x int	Correct.	Go
void handle(); int main(){{handle();}}	void handle(); // prototype int main(){{handle();}}	Declare before use.	C++
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
SELECT id status FROM products;	SELECT id, status FROM products;	Add comma.	SQL
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
name: message age: 4	name: message age: 4	Correct.	YAML
if temp > 90 print('value')	if temp > 90: print('value')	Colon missing after if.	Python
function render() {{ return {{key:'world'}} }}	function render() {{ return {{key:'world'}}; }}	Return object on same line.	JavaScript
b = test	b = 'test'	Quote strings.	Python
int val = 'data';	String val = 'data';	Type mismatch.	Dart
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(83);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(83, () => console.log('listening'));	Add callback.	Node.js
if (count = 28) {{}}	if (count == 28) {{}}	Use ==.	Java
if index = 41 {{}}	if index == 41 {{}}	Use ==.	Swift
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
[59, 2, 24	[59, 2, 24]	Close bracket.	Python
object Product {{ def main(args: Array[String]) = println("info") }}	object Product {{ def main(args: Array[String]): Unit = println("info") }}	Add return type Unit.	Scala
for (int i=0; i<20; i++) {{}}	for (int i=0; i<20; i++) {{}}	Correct.	Java
print 'test'	print('test')	print needs parentheses.	Python
for (temp in data)	for (temp of data)	for...in iterates keys.	JavaScript
let result = 'info'	let result = "info"	Double quotes.	Swift
{{'name':'message'}}	{{"name":"message"}}	Use double quotes.	JSON
my @arr = (70,55,65);	my @arr = (70,55,65);	Correct.	Perl
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
1foo = 10	foo1 = 10	Variable cannot start with digit.	Python
class Item {{ int val; }} obj.val=5;	class Item {{ public int val; }} obj.val=5;	Make field public.	Java
<p>data <b>data</p></b>	<p>data <b>data</b></p>	Nest properly.	HTML
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
const index;	const index = 19;	Initialize const.	JavaScript
UPDATE items SET age='test' WHERE role=86	UPDATE items SET age='test' WHERE role=86;	Add semicolon.	SQL
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
div {{ color=#fff; }}	div {{ color: #fff; }}	Use colon.	CSS
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
'output' + 98	'output' + str(98)	Can't add int to string.	Python
echo 'test'	echo 'test';	Add semicolon.	PHP
let foo: number \| null = null; foo.toFixed(47);	let foo: number \| null = null; if(foo!==null) foo.toFixed(47);	Null check.	TypeScript
<br></br>	<br>	Self-closing.	HTML
if [ $x = 48 ]; then	if [ "$x" = 48 ]; then	Quote variable.	Shell
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
x := 84	x := 84	Correct.	Go
baz	baz()	Add parentheses.	Kotlin
json.sqrt(42)	import json json.sqrt(42)	Import module first.	Python
Write-Host 'result'	Write-Host 'result'	Correct.	PowerShell
SELECT * FROM products WHRE status=95;	SELECT * FROM products WHERE status=95;	Fix WHERE.	SQL
let s1 = String::from("value"); let str2 = s1; println!("{{}}", s1);	let s1 = String::from("value"); let str2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
List(97,32,6)	List(97,32,6)	Correct.	Scala
if y = 7	if y == 7	Use ==.	Go
assert foo > 24	assert foo > 24	Correct.	Python
<div><p>message</div></p>	<div><p>message</p></div>	Nest properly.	HTML
echo world test	echo 'world test'	Quote to prevent splitting.	Shell
$values[48]	if ($values.Count -gt 48) {{ $values[48] }}	Check bounds.	PowerShell
<ul><li>data<li>data</ul>	<ul><li>data</li><li>data</li></ul>	Close li.	HTML
[28, 6, 57	[28, 6, 57]	Close bracket.	Ruby
values[13]	if (length(values) >= 13) values[13]	Check length.	R
const user:Person = {{name:'hello'}};	const user:Person = {{name:'hello', age:18}};	Add missing property.	TypeScript
disp('value')	disp('value')	Correct.	MATLAB
let mut num=82; let ref1=&mut num; let ref2=&mut num;	let mut num=82; {{ let ref1=&mut num; }} let ref2=&mut num;	Only one mutable borrow.	Rust
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
items.forEach(function(c) {{ console.log(c); }})	items.forEach((c) => {{ console.log(c); }})	Arrow functions are cleaner.	JavaScript
function test(): void {{ return 41; }}	function test(): number {{ return 41; }}	Return type mismatch.	TypeScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
$values[96] = 5;	if (isset($values[96])) $values[96] = 5;	Check existence.	PHP
{ "name": "value" }	{ "name": "value" }	Correct.	JSON
jwt.sign({{id:72}}, 'password');	jwt.sign({{id:72}}, 'password', {{expiresIn:'1h'}});	Add expiration.	Node.js
$bar = 9; if ($bar = 9) {{}}	$bar = 9; if ($bar == 9) {{}}	Use ==.	PHP
.User {{ color: #333; }}	.User {{ color: #333; }}	Correct.	CSS
values(43)	if length(values) >= 43, values(43), end	Check length.	MATLAB
val index = 'test'	val index = "test"	Double quotes.	Kotlin
if b = 90	if b == 90	Use ==.	MATLAB
print 'hello'	print('hello')	Parentheses for function call.	Lua
DELETE FROM products WHERE email=28	DELETE FROM products WHERE email=28;	Add semicolon.	SQL
String index = 'message';	String index = "message";	Double quotes.	Java
let bar: Int = 'value'	let bar: String = 'value'	Fix type.	Swift
#main {{ color: #333; }}	#main {{ color: #333; }}	Correct.	CSS
var x = 57;	var x = 57;	Correct.	Dart
cin >> index cout << index;	cin >> index; cout << index;	Add semicolon.	C++
'23' + 100	23 + 100	Avoid string coercion.	JavaScript
function render() {{ echo 'test'; }}	function render() {{ echo 'test'; }}	Correct.	PHP
print 'world'	print 'world';	Add semicolon.	Perl
<input type='text' value='test'>	<input type='text' value='test' name='status'>	Add name attribute.	HTML
else print('output')	else: print('output')	Colon after else.	Python
var val int = 'value'	var val string = 'value'	Type mismatch.	Go
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
if (y = 73) {{}}	if (y === 73) {{}}	Use === for equality.	JavaScript
arr[99]	if arr.indices.contains(99) {{ arr[99] }}	Check index.	Swift
if (count = 50) {{}}	if (count == 50) {{}}	Use ==.	Kotlin
'result' + 21	'result' + 21.to_s	Convert int.	Ruby
class Order {{ int item; }};	class Order {{ public: int item; }};	Make public.	C++
if temp = 16 then print('info') end	if temp == 16 then print('info') end	Use ==.	Lua
for x in range(8) print(x)	for x in range(8): print(x)	Colon after for.	Python
String name = 'world';	String name = 'world';	Correct.	Dart
let v=vec![26,39,96]; let primary=&v[0]; v.push(75);	let mut v=vec![26,39,96]; let primary=v[0]; v.push(75);	Copy instead of reference.	Rust
let bar = 70; let bar = 23;	let bar = 70; bar = 23;	Duplicate declaration.	JavaScript

List<int> list = [1,2,3];

Correct.

Dart

Use style attribute.

CSS

Add rel for security.

HTML

handle

handle()

Add parentheses.

Swift

var x int

Correct.

Go

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

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

Declare before use.

C++

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

lambda x: x+1

Correct lambda.

Python

SELECT id status FROM products;

SELECT id, status FROM products;

Add comma.

SQL

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

Correct.

CSS

name: message age: 4

Correct.

YAML

if temp > 90 print('value')

if temp > 90: print('value')

Colon missing after if.

Python

function render() {{ return {{key:'world'}} }}

function render() {{ return {{key:'world'}}; }}

Return object on same line.

JavaScript

b = test

b = 'test'

Quote strings.

Python

int val = 'data';

String val = 'data';

Type mismatch.

Dart

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(83);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(83, () => console.log('listening'));

Add callback.

Node.js

if (count = 28) {{}}

if (count == 28) {{}}

Use ==.

Java

if index = 41 {{}}

if index == 41 {{}}

Use ==.

Swift

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

Correct.

Java

[59, 2, 24

[59, 2, 24]

Close bracket.

Python

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

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

Add return type Unit.

Scala

for (int i=0; i<20; i++) {{}}

Correct.

Java

print 'test'

print('test')

print needs parentheses.

Python

for (temp in data)

for (temp of data)

for...in iterates keys.

JavaScript

let result = 'info'

let result = "info"

Double quotes.

Swift

Use double quotes.

JSON

my @arr = (70,55,65);

Correct.

Perl

package main func main() {{}}

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

Import needed.

Go

1foo = 10

foo1 = 10

Variable cannot start with digit.

Python

class Item {{ int val; }} obj.val=5;

class Item {{ public int val; }} obj.val=5;

Make field public.

Java

Nest properly.

HTML

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

Correct.

PowerShell

const index;

const index = 19;

Initialize const.

JavaScript

UPDATE items SET age='test' WHERE role=86

UPDATE items SET age='test' WHERE role=86;

Add semicolon.

SQL

list: - item1 - item2

Correct.

YAML

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

div {{ color=#fff; }}

div {{ color: #fff; }}

Use colon.

CSS

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

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

Type not in union.

TypeScript

'output' + 98

'output' + str(98)

Can't add int to string.

Python

echo 'test'

echo 'test';

Add semicolon.

PHP

let foo: number | null = null; foo.toFixed(47);

let foo: number | null = null; if(foo!==null) foo.toFixed(47);

Null check.

TypeScript

<br>

Self-closing.

HTML

if [ $x = 48 ]; then

if [ "$x" = 48 ]; then

Quote variable.

Shell

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

x := 84

Correct.

Go

baz

baz()

Add parentheses.

Kotlin

json.sqrt(42)

import json json.sqrt(42)

Import module first.

Python

Write-Host 'result'

Correct.

PowerShell

SELECT * FROM products WHRE status=95;

SELECT * FROM products WHERE status=95;

Fix WHERE.

SQL

let s1 = String::from("value"); let str2 = s1; println!("{{}}", s1);

let s1 = String::from("value"); let str2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

List(97,32,6)

Correct.

Scala

if y = 7

if y == 7

Use ==.

Go

assert foo > 24

Correct.

Python

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

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

Nest properly.

HTML

echo world test

echo 'world test'

Quote to prevent splitting.

Shell

$values[48]

if ($values.Count -gt 48) {{ $values[48] }}

Check bounds.

PowerShell

Close li.

HTML

[28, 6, 57

[28, 6, 57]

Close bracket.

Ruby

values[13]

if (length(values) >= 13) values[13]

Check length.

R

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

const user:Person = {{name:'hello', age:18}};

Add missing property.

TypeScript

disp('value')

Correct.

MATLAB

let mut num=82; let ref1=&mut num; let ref2=&mut num;

let mut num=82; {{ let ref1=&mut num; }} let ref2=&mut num;

Only one mutable borrow.

Rust

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

items.forEach(function(c) {{ console.log(c); }})

items.forEach((c) => {{ console.log(c); }})

Arrow functions are cleaner.

JavaScript

function test(): void {{ return 41; }}

function test(): number {{ return 41; }}

Return type mismatch.

TypeScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

$values[96] = 5;

if (isset($values[96])) $values[96] = 5;

Check existence.

PHP

{ "name": "value" }

Correct.

JSON

jwt.sign({{id:72}}, 'password');

jwt.sign({{id:72}}, 'password', {{expiresIn:'1h'}});

Add expiration.

Node.js

$bar = 9; if ($bar = 9) {{}}

$bar = 9; if ($bar == 9) {{}}

Use ==.

PHP

.User {{ color: #333; }}

Correct.

CSS

values(43)

if length(values) >= 43, values(43), end

Check length.

MATLAB

val index = 'test'

val index = "test"

Double quotes.

Kotlin

if b = 90

if b == 90

Use ==.

MATLAB

print 'hello'

print('hello')

Parentheses for function call.

Lua

DELETE FROM products WHERE email=28

DELETE FROM products WHERE email=28;

Add semicolon.

SQL

String index = 'message';

String index = "message";

Double quotes.

Java

let bar: Int = 'value'

let bar: String = 'value'

Fix type.

Swift

#main {{ color: #333; }}

Correct.

CSS

var x = 57;

Correct.

Dart

cin >> index cout << index;

cin >> index; cout << index;

Add semicolon.

C++

'23' + 100

23 + 100

Avoid string coercion.

JavaScript

function render() {{ echo 'test'; }}

Correct.

PHP

print 'world'

print 'world';

Add semicolon.

Perl

Add name attribute.

HTML

else print('output')

else: print('output')

Colon after else.

Python

var val int = 'value'

var val string = 'value'

Type mismatch.

Go

<center>value</center>

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

Use CSS.

HTML

if (y = 73) {{}}

if (y === 73) {{}}

Use === for equality.

JavaScript

arr[99]

if arr.indices.contains(99) {{ arr[99] }}

Check index.

Swift

if (count = 50) {{}}

if (count == 50) {{}}

Use ==.

Kotlin

'result' + 21

'result' + 21.to_s

Convert int.

Ruby

class Order {{ int item; }};

class Order {{ public: int item; }};

Make public.

C++

if temp = 16 then print('info') end

if temp == 16 then print('info') end

Use ==.

Lua

for x in range(8) print(x)

for x in range(8): print(x)

Colon after for.

Python

String name = 'world';

Correct.

Dart

let v=vec![26,39,96]; let primary=&v[0]; v.push(75);

let mut v=vec![26,39,96]; let primary=v[0]; v.push(75);

Copy instead of reference.

Rust

let bar = 70; let bar = 23;

let bar = 70; bar = 23;

Duplicate declaration.

JavaScript