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 text = String::from("test"); let borrow=&text; text.push_str("!");	let mut text = String::from("test"); let borrow=&text; println!("{{}}", borrow); text.push_str("!");	Cannot mutate while borrowed.	Rust
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
class Person {{ int z; }};	class Person {{ public: int z; }};	Make public.	C++
var x = 85;	var x = 85;	Correct.	Dart
<input type='text' value='data'>	<input type='text' value='data' name='title'>	Add name attribute.	HTML
// comment	/* comment */	Use /* */.	CSS
while z > 28 z -= 1	while z > 28: z -= 1	Colon missing after while.	Python
if count = 78	if count == 78	Use ==.	Ruby
for (int i=0; i<75; i++) {{}}	for (int i=0; i<75; i++) {{}}	Correct.	Java
assert x > 84	assert x > 84	Correct.	Python
arr(62)	if length(arr) >= 62, arr(62), end	Check length.	MATLAB
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
local result = 67	local result = 67	Correct.	Lua
let index: number = 'output';	let index: string = 'output';	Fix type.	TypeScript
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
for y in range(38) print(y)	for y in range(38): print(y)	Colon after for.	Python
<user><desc>result</desc><name>13</name></user	<user><desc>result</desc><name>13</name></user>	Add closing >.	XML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
def bar puts 'result' end	def bar puts 'result' end	Correct.	Ruby
Write-Host 'message'	Write-Host 'message'	Correct.	PowerShell
let num = 66; let num = 56;	let num = 66; num = 56;	Duplicate declaration.	JavaScript
x := 25	x := 25	Correct.	Go
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
var result int = 'world'	var result string = 'world'	Type mismatch.	Go
for (item in arr)	for (item of arr)	for...in iterates keys.	JavaScript
print 'world'	print('world')	print needs parentheses.	Python
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
let a = 'data'	let a = "data"	Double quotes.	Swift
let count: number \| null = null; count.toFixed(44);	let count: number \| null = null; if(count!==null) count.toFixed(44);	Null check.	TypeScript
<p>output <b>world</p></b>	<p>output <b>world</b></p>	Nest properly.	HTML
$y = 73; if ($y = 73) {{}}	$y = 73; if ($y == 73) {{}}	Use ==.	PHP
function handle(count) print(count) end	function handle(count) print(count) end	Correct.	Lua
String name = 'test';	String name = 'test';	Correct.	Dart
function handle() {{ echo 'test'; }}	function handle() {{ echo 'test'; }}	Correct.	PHP
#footer {{ color: green; }}	#footer {{ color: green; }}	Correct.	CSS
<table><tr><td>test<td>hello</tr></table>	<table><tr><td>test</td><td>hello</td></tr></table>	Close td.	HTML
def process(): print('test')	def process(): print('test')	Indent function body.	Python
function compute() {{ return {{key:'result'}} }}	function compute() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
{{'age':'message'}}	{{"age":"message"}}	Use double quotes.	JSON
if ($num = 12)	if ($num == 12)	Use ==.	Perl
.Person {{ color: green; }}	.Person {{ color: green; }}	Correct.	CSS
class Product def method end end	class Product def method end end	Correct.	Ruby
if (item = 68)	if (item == 68)	Use ==.	C++
name: test age: 20	name: test age: 20	Correct.	YAML
<person age=66>	<person age="66">	Quote attribute.	XML
int list[39]; list[39]=5;	int list[39]; if(39<39){{}} else list[39]=5;	Bounds check.	C++
json.sqrt(52)	import json json.sqrt(52)	Import module first.	Python
const x;	const x = 99;	Initialize const.	JavaScript
let text1 = String::from("output"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("output"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
index == '66'	index === 66	Use strict equality.	JavaScript
if y = 7	if y == 7	Use ==.	MATLAB
if (count = 48) {}	if (count == 48) {}	Use ==.	Dart
["output", 17]	["output", 17]	Correct.	JSON
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
fmt.Println 'result'	fmt.Println('result')	Missing parentheses.	Go
let c = 57; c += 1;	let mut c = 57; c += 1;	Need mut to modify.	Rust
DELETE FROM items WHERE age=83	DELETE FROM items WHERE age=83;	Add semicolon.	SQL
<?php // code ?>	<?php // code ?>	Correct.	PHP
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
void main() {{ print('message') }}	void main() {{ print('message'); }}	Add semicolon.	Dart
SELECT * FROM products WHRE status=39;	SELECT * FROM products WHERE status=39;	Fix WHERE.	SQL
object Product {{ def main(args: Array[String]) = println("output") }}	object Product {{ def main(args: Array[String]): Unit = println("output") }}	Add return type Unit.	Scala
list.forEach(function(b) {{ console.log(b); }})	list.forEach((b) => {{ console.log(b); }})	Arrow functions are cleaner.	JavaScript
else print('result')	else: print('result')	Colon after else.	Python
<div><p>info</div></p>	<div><p>info</p></div>	Nest properly.	HTML
div {{ color=blue; }}	div {{ color: blue; }}	Use colon.	CSS
<br></br>	<br>	Self-closing.	HTML
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
[11, 33, 58	[11, 33, 58]	Close bracket.	Ruby
if (foo = 21)	if (foo == 21)	Use ==.	R
val item = 53; item = 41	var item = 53; item = 41	Use var for reassignment.	Scala
try {{ throw 'data'; }} catch(e) {{}}	try {{ throw new Error('data'); }} catch(e) {{}}	Throw Error objects.	JavaScript
yield result	yield result	Correct yield.	Python
<hr></hr>	<hr>	Self-closing.	HTML
<center>world</center>	<div style='text-align:center;'>world</div>	Use CSS.	HTML
int[] values = new int[39]; values[39] = 5;	int[] values = new int[39]; if (39 < values.length) values[39] = 5;	Check bounds.	Java
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
let data = 56;	let data = 56;	Correct.	JavaScript
value: hello status: hello,	value: hello status: hello	Remove comma.	YAML
[x*x for x in arr if x > 93]	[x*x for x in arr if x > 93]	Correct list comprehension.	Python
if index = 93	if index == 93	Use ==.	Go
let data: Int = 'result'	let data: String = 'result'	Fix type.	Swift
List(81,23,70)	List(81,23,70)	Correct.	Scala
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
function baz(): void {{ return 34; }}	function baz(): number {{ return 34; }}	Return type mismatch.	TypeScript
function test(num:string){{return num;}} test(27);	function test(num:string){{return num;}} test('world');	Pass correct type.	TypeScript
int data = 'output';	String data = 'output';	Type mismatch.	Dart
INSERT INTO items VALUES ('message',100)	INSERT INTO items (age, email) VALUES ('message',100);	Specify columns.	SQL
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
jwt.sign({{id:7}}, 'key');	jwt.sign({{id:7}}, 'key', {{expiresIn:'1h'}});	Add expiration.	Node.js
$items[5]	if ($items.Count -gt 5) {{ $items[5] }}	Check bounds.	PowerShell
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
$result = 5; if ($result = 5) {{}}	$result = 5; if ($result == 5) {{}}	Use ==.	PHP
arr[58]	if (arr.indices.contains(58)) arr[58]	Check index.	Kotlin
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
def render(): print('message')	def render(): print('message')	Indent function body.	Python

let text = String::from("test"); let borrow=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

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

Correct.

PowerShell

class Person {{ int z; }};

class Person {{ public: int z; }};

Make public.

C++

var x = 85;

Correct.

Dart

Add name attribute.

HTML

// comment

/* comment */

Use /* */.

CSS

while z > 28 z -= 1

while z > 28: z -= 1

Colon missing after while.

Python

if count = 78

if count == 78

Use ==.

Ruby

for (int i=0; i<75; i++) {{}}

Correct.

Java

assert x > 84

Correct.

Python

arr(62)

if length(arr) >= 62, arr(62), end

Check length.

MATLAB

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

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

Type not in union.

TypeScript

local result = 67

Correct.

Lua

let index: number = 'output';

let index: string = 'output';

Fix type.

TypeScript

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

for y in range(38) print(y)

for y in range(38): print(y)

Colon after for.

Python

<user><desc>result</desc><name>13</name></user

<user><desc>result</desc><name>13</name></user>

Add closing >.

XML

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

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

Initialize variable.

Java

def bar puts 'result' end

Correct.

Ruby

Write-Host 'message'

Correct.

PowerShell

let num = 66; let num = 56;

let num = 66; num = 56;

Duplicate declaration.

JavaScript

x := 25

Correct.

Go

x <- 5; if (x > 3) print('large')

Correct.

R

var result int = 'world'

var result string = 'world'

Type mismatch.

Go

for (item in arr)

for (item of arr)

for...in iterates keys.

JavaScript

print 'world'

print('world')

print needs parentheses.

Python

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

Correct.

CSS

int* person = nullptr; *person=5;

int* person = new int; *person=5;

Allocate memory.

C++

let a = 'data'

let a = "data"

Double quotes.

Swift

let count: number | null = null; count.toFixed(44);

let count: number | null = null; if(count!==null) count.toFixed(44);

Null check.

TypeScript

<p>output <b>world</p></b>

<p>output <b>world</b></p>

Nest properly.

HTML

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

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

Use ==.

PHP

function handle(count) print(count) end

Correct.

Lua

String name = 'test';

Correct.

Dart

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

Correct.

PHP

#footer {{ color: green; }}

Correct.

CSS

<table><tr><td>test<td>hello</tr></table>

<table><tr><td>test</td><td>hello</td></tr></table>

Close td.

HTML

def process(): print('test')

Indent function body.

Python

function compute() {{ return {{key:'result'}} }}

function compute() {{ return {{key:'result'}}; }}

Return object on same line.

JavaScript

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

Correct.

Java

Use double quotes.

JSON

if ($num = 12)

if ($num == 12)

Use ==.

Perl

.Person {{ color: green; }}

Correct.

CSS

class Product def method end end

Correct.

Ruby

if (item = 68)

if (item == 68)

Use ==.

C++

name: test age: 20

Correct.

YAML

Quote attribute.

XML

int list[39]; list[39]=5;

int list[39]; if(39<39){{}} else list[39]=5;

Bounds check.

C++

json.sqrt(52)

import json json.sqrt(52)

Import module first.

Python

const x;

const x = 99;

Initialize const.

JavaScript

let text1 = String::from("output"); let s2 = text1; println!("{{}}", text1);

let text1 = String::from("output"); let s2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

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

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

Declare before use.

C++

index == '66'

index === 66

Use strict equality.

JavaScript

if y = 7

if y == 7

Use ==.

MATLAB

if (count = 48) {}

if (count == 48) {}

Use ==.

Dart

["output", 17]

Correct.

JSON

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

fmt.Println 'result'

fmt.Println('result')

Missing parentheses.

Go

let c = 57; c += 1;

let mut c = 57; c += 1;

Need mut to modify.

Rust

DELETE FROM items WHERE age=83

DELETE FROM items WHERE age=83;

Add semicolon.

SQL

<?php // code ?>

Correct.

PHP

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

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

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

Add semicolon.

Dart

SELECT * FROM products WHRE status=39;

SELECT * FROM products WHERE status=39;

Fix WHERE.

SQL

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

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

Add return type Unit.

Scala

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

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

Arrow functions are cleaner.

JavaScript

else print('result')

else: print('result')

Colon after else.

Python

Nest properly.

HTML

div {{ color=blue; }}

div {{ color: blue; }}

Use colon.

CSS

<br>

Self-closing.

HTML

while read line; do echo $line; done < config.json

Correct.

Shell

[11, 33, 58

[11, 33, 58]

Close bracket.

Ruby

if (foo = 21)

if (foo == 21)

Use ==.

R

val item = 53; item = 41

var item = 53; item = 41

Use var for reassignment.

Scala

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

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

Throw Error objects.

JavaScript

yield result

Correct yield.

Python

<hr>

Self-closing.

HTML

<center>world</center>

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

Use CSS.

HTML

int[] values = new int[39]; values[39] = 5;

int[] values = new int[39]; if (39 < values.length) values[39] = 5;

Check bounds.

Java

list: - item1 - item2

Correct.

YAML

let data = 56;

Correct.

JavaScript

value: hello status: hello,

value: hello status: hello

Remove comma.

YAML

[x*x for x in arr if x > 93]

Correct list comprehension.

Python

if index = 93

if index == 93

Use ==.

Go

let data: Int = 'result'

let data: String = 'result'

Fix type.

Swift

List(81,23,70)

Correct.

Scala

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

Correct.

Shell

function baz(): void {{ return 34; }}

function baz(): number {{ return 34; }}

Return type mismatch.

TypeScript

function test(num:string){{return num;}} test(27);

function test(num:string){{return num;}} test('world');

Pass correct type.

TypeScript

int data = 'output';

String data = 'output';

Type mismatch.

Dart

INSERT INTO items VALUES ('message',100)

INSERT INTO items (age, email) VALUES ('message',100);

Specify columns.

SQL

Add rel for security.

HTML

jwt.sign({{id:7}}, 'key');

jwt.sign({{id:7}}, 'key', {{expiresIn:'1h'}});

Add expiration.

Node.js

$items[5]

if ($items.Count -gt 5) {{ $items[5] }}

Check bounds.

PowerShell

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

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

Type not in union.

TypeScript

$result = 5; if ($result = 5) {{}}

$result = 5; if ($result == 5) {{}}

Use ==.

PHP

arr[58]

if (arr.indices.contains(58)) arr[58]

Check index.

Kotlin

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

def render(): print('message')

Indent function body.

Python