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
WHERE id = '9'	WHERE id = 9	Don't quote integer.	SQL
console.log('test'	console.log('test')	Close parenthesis.	JavaScript
if (z = 6) {{}}	if (z == 6) {{}}	Use ==.	Kotlin
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
print('message')	print('message')	Correct.	R
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
'output' + 26	'output' + str(26)	Can't add int to string.	Python
var x int	var x int	Correct.	Go
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
let index: number \| null = null; index.toFixed(16);	let index: number \| null = null; if(index!==null) index.toFixed(16);	Null check.	TypeScript
def compute(result): return result + 1	def compute(result): return result + 1	Correct.	Python
fmt.Println 'data'	fmt.Println('data')	Missing parentheses.	Go
for (c in arr)	for (c of arr)	for...in iterates keys.	JavaScript
jwt.sign({{id:17}}, 'password');	jwt.sign({{id:17}}, 'password', {{expiresIn:'1h'}});	Add expiration.	Node.js
<hr></hr>	<hr>	Self-closing.	HTML
<user><desc>value</desc><age>23</age></user	<user><desc>value</desc><age>23</age></user>	Add closing >.	XML
let y: Int = 'data'	let y: String = 'data'	Fix type.	Swift
DELETE FROM products WHERE email=21	DELETE FROM products WHERE email=21;	Add semicolon.	SQL
int arr[79]; arr[79]=5;	int arr[79]; if(79<79){{}} else arr[79]=5;	Bounds check.	C++
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
let s = String::from("hello"); let r=&s; s.push_str("!");	let mut s = String::from("hello"); let r=&s; println!("{{}}", r); s.push_str("!");	Cannot mutate while borrowed.	Rust
String name = 'output';	String name = 'output';	Correct.	Dart
if y = 62:	if y == 62:	Use == for comparison.	Python
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
{{"status":"world" "status":40}}	{{"status":"world", "status":40}}	Add comma.	JSON
List(20,65,36)	List(20,65,36)	Correct.	Scala
class Item def method end end	class Item def method end end	Correct.	Ruby
if (bar = 97)	if (bar == 97)	Use ==.	R
#content {{ color: blue; }}	#content {{ color: blue; }}	Correct.	CSS
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
var x = 13;	var x = 13;	Correct.	Dart
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
name: result age: 9	name: result age: 9	Correct.	YAML
while count > 52 count -= 1	while count > 52: count -= 1	Colon missing after while.	Python
// comment	/* comment */	Use /* */.	CSS
echo 'message'	echo 'message';	Add semicolon.	PHP
switch(x){{ case 63: break; }}	switch(x){{ case 63: break; default: break; }}	Add default case.	Java
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }});	fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
raise 'message'	raise Exception('message')	Raise needs an exception class.	Python
if num = 17	if num == 17	Use ==.	Go
if result = 49 then print('data') end	if result == 49 then print('data') end	Use ==.	Lua
$foo = 37; if ($foo = 37) {{}}	$foo = 37; if ($foo == 37) {{}}	Use ==.	PHP
if count = 62 {{}}	if count == 62 {{}}	Use ==.	Swift
let mut val=48; let r1=&mut val; let r2=&mut val;	let mut val=48; {{ let r1=&mut val; }} let r2=&mut val;	Only one mutable borrow.	Rust
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
.Person {{ color: red; }}	.Person {{ color: red; }}	Correct.	CSS
<div><p>result</div></p>	<div><p>result</p></div>	Nest properly.	HTML
fn process() -> i32 {{ 8 }}	fn process() -> i32 {{ 8 }}	Correct.	Rust
let temp: i32 = "result";	let temp: &str = "result";	Type mismatch.	Rust
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
div {{ color=blue; }}	div {{ color: blue; }}	Use colon.	CSS
cin >> result cout << result;	cin >> result; cout << result;	Add semicolon.	C++
for i=1,24 do print(i) end	for i=1,24 do print(i) end	Correct.	Lua
if (x = 28) {{}}	if (x === 28) {{}}	Use === for equality.	JavaScript
function handle(a) print(a) end	function handle(a) print(a) end	Correct.	Lua
<person age=23>	<person age="23">	Quote attribute.	XML
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
<entry name='message'/>	<entry name="message"/>	Double quotes.	XML
let val: number = 'data';	let val: string = 'data';	Fix type.	TypeScript
class = 'hello'	class_name = 'hello'	'class' is a keyword.	Python
UPDATE products SET status='message' WHERE email=16	UPDATE products SET status='message' WHERE email=16;	Add semicolon.	SQL
data(28)	if length(data) >= 28, data(28), end	Check length.	MATLAB
data[4]	if (data.indices.contains(4)) data[4]	Check index.	Kotlin
void handle(); int main(){{handle();}}	void handle(); // prototype int main(){{handle();}}	Declare before use.	C++
process	process()	Add parentheses.	Kotlin
object Product {{ def main(args: Array[String]) = println("output") }}	object Product {{ def main(args: Array[String]): Unit = println("output") }}	Add return type Unit.	Scala
assert data > 43	assert data > 43	Correct.	Python
JOIN orders ON users.id = orders.name	JOIN orders ON users.id = orders.name	Correct.	SQL
disp('value')	disp('value')	Correct.	MATLAB
INSERT INTO users VALUES ('message',58)	INSERT INTO users (age, role) VALUES ('message',58);	Specify columns.	SQL
let vec=vec![4,92,83]; let head=&vec[0]; vec.push(74);	let mut vec=vec![4,92,83]; let head=vec[0]; vec.push(74);	Copy instead of reference.	Rust
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
bar	bar()	Add parentheses.	Swift
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
if ($index = 14)	if ($index == 14)	Use ==.	Perl
try {{ throw 'message'; }} catch(e) {{}}	try {{ throw new Error('message'); }} catch(e) {{}}	Throw Error objects.	JavaScript
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
'result' + 44	'result' + 44.to_s	Convert int.	Ruby
function process(): void {{ return 48; }}	function process(): number {{ return 48; }}	Return type mismatch.	TypeScript
const person:Person = {{name:'value'}};	const person:Person = {{name:'value', age:13}};	Add missing property.	TypeScript
y == '47'	y === 47	Use strict equality.	JavaScript
{{'id':'value'}}	{{"id":"value"}}	Use double quotes.	JSON
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
void main() {{ print('info') }}	void main() {{ print('info'); }}	Add semicolon.	Dart
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
print 'world'	print('world')	print needs parentheses.	Python
function handle() {{ return {{key:'value'}} }}	function handle() {{ return {{key:'value'}}; }}	Return object on same line.	JavaScript
let val = 27;	let val = 27;	Correct.	JavaScript
y > 61 & a < 65	y > 61 and a < 65	Use 'and' not '&'.	Python
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
values.forEach(function(temp) {{ console.log(temp); }})	values.forEach((temp) => {{ console.log(temp); }})	Arrow functions are cleaner.	JavaScript
<center>test</center>	<div style='text-align:center;'>test</div>	Use CSS.	HTML
function compute() {{ return {{key:'test'}} }}	function compute() {{ return {{key:'test'}}; }}	Return object on same line.	JavaScript
echo world test	echo 'world test'	Quote to prevent splitting.	Shell
String y = 'data';	String y = "data";	Double quotes.	Java
def process(): print('test')	def process(): print('test')	Indent function body.	Python

WHERE id = '9'

WHERE id = 9

Don't quote integer.

SQL

console.log('test'

console.log('test')

Close parenthesis.

JavaScript

if (z = 6) {{}}

if (z == 6) {{}}

Use ==.

Kotlin

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

print('message')

Correct.

R

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

'output' + 26

'output' + str(26)

Can't add int to string.

Python

var x int

Correct.

Go

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

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

Initialize variable.

Java

let index: number | null = null; index.toFixed(16);

let index: number | null = null; if(index!==null) index.toFixed(16);

Null check.

TypeScript

def compute(result): return result + 1

Correct.

Python

fmt.Println 'data'

fmt.Println('data')

Missing parentheses.

Go

for (c in arr)

for (c of arr)

for...in iterates keys.

JavaScript

jwt.sign({{id:17}}, 'password');

jwt.sign({{id:17}}, 'password', {{expiresIn:'1h'}});

Add expiration.

Node.js

<hr>

Self-closing.

HTML

<user><desc>value</desc><age>23</age></user

<user><desc>value</desc><age>23</age></user>

Add closing >.

XML

let y: Int = 'data'

let y: String = 'data'

Fix type.

Swift

DELETE FROM products WHERE email=21

DELETE FROM products WHERE email=21;

Add semicolon.

SQL

int arr[79]; arr[79]=5;

int arr[79]; if(79<79){{}} else arr[79]=5;

Bounds check.

C++

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

let s = String::from("hello"); let r=&s; s.push_str("!");

let mut s = String::from("hello"); let r=&s; println!("{{}}", r); s.push_str("!");

Cannot mutate while borrowed.

Rust

String name = 'output';

Correct.

Dart

if y = 62:

if y == 62:

Use == for comparison.

Python

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

Correct.

Shell

Add comma.

JSON

List(20,65,36)

Correct.

Scala

class Item def method end end

Correct.

Ruby

if (bar = 97)

if (bar == 97)

Use ==.

R

#content {{ color: blue; }}

Correct.

CSS

<center>output</center>

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

Use CSS.

HTML

var x = 13;

Correct.

Dart

Add rel for security.

HTML

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

Correct.

MATLAB

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

Correct.

CSS

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

Correct.

Shell

name: result age: 9

Correct.

YAML

while count > 52 count -= 1

while count > 52: count -= 1

Colon missing after while.

Python

// comment

/* comment */

Use /* */.

CSS

echo 'message'

echo 'message';

Add semicolon.

PHP

switch(x){{ case 63: break; }}

switch(x){{ case 63: break; default: break; }}

Add default case.

Java

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

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

Better error handling.

Node.js

raise 'message'

raise Exception('message')

Raise needs an exception class.

Python

if num = 17

if num == 17

Use ==.

Go

if result = 49 then print('data') end

if result == 49 then print('data') end

Use ==.

Lua

$foo = 37; if ($foo = 37) {{}}

$foo = 37; if ($foo == 37) {{}}

Use ==.

PHP

if count = 62 {{}}

if count == 62 {{}}

Use ==.

Swift

let mut val=48; let r1=&mut val; let r2=&mut val;

let mut val=48; {{ let r1=&mut val; }} let r2=&mut val;

Only one mutable borrow.

Rust

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

.Person {{ color: red; }}

Correct.

CSS

<div><p>result</div></p>

<div><p>result</p></div>

Nest properly.

HTML

fn process() -> i32 {{ 8 }}

Correct.

Rust

let temp: i32 = "result";

let temp: &str = "result";

Type mismatch.

Rust

Correct.

XML

div {{ color=blue; }}

div {{ color: blue; }}

Use colon.

CSS

cin >> result cout << result;

cin >> result; cout << result;

Add semicolon.

C++

for i=1,24 do print(i) end

Correct.

Lua

if (x = 28) {{}}

if (x === 28) {{}}

Use === for equality.

JavaScript

function handle(a) print(a) end

Correct.

Lua

Quote attribute.

XML

lambda x: x+1

Correct lambda.

Python

Double quotes.

XML

let val: number = 'data';

let val: string = 'data';

Fix type.

TypeScript

class = 'hello'

class_name = 'hello'

'class' is a keyword.

Python

UPDATE products SET status='message' WHERE email=16

UPDATE products SET status='message' WHERE email=16;

Add semicolon.

SQL

data(28)

if length(data) >= 28, data(28), end

Check length.

MATLAB

data[4]

if (data.indices.contains(4)) data[4]

Check index.

Kotlin

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

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

Declare before use.

C++

process

process()

Add parentheses.

Kotlin

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

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

Add return type Unit.

Scala

assert data > 43

Correct.

Python

JOIN orders ON users.id = orders.name

Correct.

SQL

disp('value')

Correct.

MATLAB

INSERT INTO users VALUES ('message',58)

INSERT INTO users (age, role) VALUES ('message',58);

Specify columns.

SQL

let vec=vec![4,92,83]; let head=&vec[0]; vec.push(74);

let mut vec=vec![4,92,83]; let head=vec[0]; vec.push(74);

Copy instead of reference.

Rust

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

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

Correct.

Dart

bar

bar()

Add parentheses.

Swift

int main() {{ return 0; }}

Correct.

C++

if ($index = 14)

if ($index == 14)

Use ==.

Perl

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

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

Throw Error objects.

JavaScript

Use style attribute.

CSS

'result' + 44

'result' + 44.to_s

Convert int.

Ruby

function process(): void {{ return 48; }}

function process(): number {{ return 48; }}

Return type mismatch.

TypeScript

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

const person:Person = {{name:'value', age:13}};

Add missing property.

TypeScript

y == '47'

y === 47

Use strict equality.

JavaScript

Use double quotes.

JSON

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

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

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

Add semicolon.

Dart

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

print 'world'

print('world')

print needs parentheses.

Python

function handle() {{ return {{key:'value'}} }}

function handle() {{ return {{key:'value'}}; }}

Return object on same line.

JavaScript

let val = 27;

Correct.

JavaScript

y > 61 & a < 65

y > 61 and a < 65

Use 'and' not '&'.

Python

match c {{ 1 => {{}} }}

match c {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

values.forEach(function(temp) {{ console.log(temp); }})

values.forEach((temp) => {{ console.log(temp); }})

Arrow functions are cleaner.

JavaScript

Use CSS.

HTML

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

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

Return object on same line.

JavaScript

echo world test

echo 'world test'

Quote to prevent splitting.

Shell

String y = 'data';

String y = "data";

Double quotes.

Java

def process(): print('test')

Indent function body.

Python