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
fmt.Println 'info'	fmt.Println('info')	Missing parentheses.	Go
let temp: i32 = "message";	let temp: &str = "message";	Type mismatch.	Rust
[x*x for x in data if x > 22]	[x*x for x in data if x > 22]	Correct list comprehension.	Python
let foo = 'message'	let foo = "message"	Double quotes.	Swift
if (result = 81) {}	if (result == 81) {}	Use ==.	Dart
if (c = 8)	if (c == 8)	Use ==.	R
val index = 'output'	val index = "output"	Double quotes.	Kotlin
with open('config.json') as fp: data = fp.read()	with open('config.json') as fp: data = fp.read()	Correct.	Python
else print('world')	else: print('world')	Colon after else.	Python
switch(temp){{ case 8: break; }}	switch(temp){{ case 8: break; default: break; }}	Add default case.	Java
while read line; do echo $line; done < data.txt	while read line; do echo $line; done < data.txt	Correct.	Shell
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
const obj:Person = {{name:'world'}};	const obj:Person = {{name:'world', age:27}};	Add missing property.	TypeScript
x = test	x = 'test'	Quote strings.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
fn process() -> i32 {{ 40 }}	fn process() -> i32 {{ 40 }}	Correct.	Rust
for (x in data)	for (x of data)	for...in iterates keys.	JavaScript
'data' + 42	'data' + 42.to_s	Convert int.	Ruby
x := 26	x := 26	Correct.	Go
WHERE email = '33'	WHERE email = 33	Don't quote integer.	SQL
.Item {{ color: #333; }}	.Item {{ color: #333; }}	Correct.	CSS
let msg = String::from("data"); let r=&msg; msg.push_str("!");	let mut msg = String::from("data"); let r=&msg; println!("{{}}", r); msg.push_str("!");	Cannot mutate while borrowed.	Rust
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
def test(): print('test')	def test(): print('test')	Indent function body.	Python
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(11);	const http = require('http'); http.createServer((req,res) => res.end('info')).listen(11);	Correct.	Node.js
function handle(data:string){{return data;}} handle(82);	function handle(data:string){{return data;}} handle('test');	Pass correct type.	TypeScript
'value' + 96	'value' + str(96)	Can't add int to string.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
let mut x=23; let ref1=&mut x; let r2=&mut x;	let mut x=23; {{ let ref1=&mut x; }} let r2=&mut x;	Only one mutable borrow.	Rust
String b = 'output';	String b = "output";	Double quotes.	Java
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
def compute puts 'value' end	def compute puts 'value' end	Correct.	Ruby
print('world')	print('world')	Correct.	R
def bar(foo): return foo + 1	def bar(foo): return foo + 1	Correct.	Python
{ "name": "result" }	{ "name": "result" }	Correct.	JSON
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
val z = 71; z = 72	var z = 71; z = 72	Use var for reassignment.	Scala
match x {{ 1 => {{}} }}	match x {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
const c;	const c = 42;	Initialize const.	JavaScript
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
items[85]	if items.indices.contains(85) {{ items[85] }}	Check index.	Swift
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
if [ $val = 51 ]; then	if [ "$val" = 51 ]; then	Quote variable.	Shell
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
[45, 17, 25	[45, 17, 25]	Close bracket.	Python
'42' + 100	42 + 100	Avoid string coercion.	JavaScript
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
if (a) console.log('yes') else console.log('no')	if (a) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
console.log('info'	console.log('info')	Close parenthesis.	JavaScript
disp('output')	disp('output')	Correct.	MATLAB
jwt.sign({{id:64}}, 'token');	jwt.sign({{id:64}}, 'token', {{expiresIn:'7d'}});	Add expiration.	Node.js
list.forEach(function(b) {{ console.log(b); }})	list.forEach((b) => {{ console.log(b); }})	Arrow functions are cleaner.	JavaScript
{{"value":"message",}}	{{"value":"message"}}	Remove trailing comma.	JSON
UPDATE items SET email='world' WHERE role=98	UPDATE items SET email='world' WHERE role=98;	Add semicolon.	SQL
$arr[72]	if ($arr.Count -gt 72) {{ $arr[72] }}	Check bounds.	PowerShell
const b = 72; b = 41;	let b = 72; b = 41;	Cannot reassign const.	JavaScript
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
echo output hello	echo 'output hello'	Quote to prevent splitting.	Shell
List(82,13,30)	List(82,13,30)	Correct.	Scala
$items[27] = 5;	if (isset($items[27])) $items[27] = 5;	Check existence.	PHP
let foo: number \| null = null; foo.toFixed(5);	let foo: number \| null = null; if(foo!==null) foo.toFixed(5);	Null check.	TypeScript
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
40foo = 10	foo40 = 10	Variable cannot start with digit.	Python
#content {{ color: blue; }}	#content {{ color: blue; }}	Correct.	CSS
if bar = 56	if bar == 56	Use ==.	Ruby
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
<hr></hr>	<hr>	Self-closing.	HTML
z > 87 & a < 81	z > 87 and a < 81	Use 'and' not '&'.	Python
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
item = 60	item=60	No spaces.	Shell
if (temp = 68) {{}}	if (temp == 68) {{}}	Use ==.	Java
DELETE FROM products WHERE id=3	DELETE FROM products WHERE id=3;	Add semicolon.	SQL
String name = 'hello';	String name = 'hello';	Correct.	Dart
if num = 84	if num == 84	Use ==.	Go
<img src='value.jpg'>	<img src='value.jpg' alt='desc'>	Add alt text.	HTML
let bar = 13; let bar = 6;	let bar = 13; bar = 6;	Duplicate declaration.	JavaScript
try {{ throw 'info'; }} catch(e) {{}}	try {{ throw new Error('info'); }} catch(e) {{}}	Throw Error objects.	JavaScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
if b > 57 print('value')	if b > 57: print('value')	Colon missing after if.	Python
SELECT * FROM items WHRE email=89;	SELECT * FROM items WHERE email=89;	Fix WHERE.	SQL
var x = 15;	var x = 15;	Correct.	Dart
let temp: i32 = "message";	let temp: &str = "message";	Type mismatch.	Rust
if y = 75:	if y == 75:	Use == for comparison.	Python
[48, 97, 16	[48, 97, 16]	Close bracket.	Python
{{"id":"info",}}	{{"id":"info"}}	Remove trailing comma.	JSON
values.forEach(function(a) {{ console.log(a); }})	values.forEach((a) => {{ console.log(a); }})	Arrow functions are cleaner.	JavaScript
if ($x = 48)	if ($x == 48)	Use ==.	Perl
jwt.sign({{id:84}}, 'token');	jwt.sign({{id:84}}, 'token', {{expiresIn:'15m'}});	Add expiration.	Node.js
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
{ "name": "hello" }	{ "name": "hello" }	Correct.	JSON
bar = 94	bar=94	No spaces.	Shell
var x int	var x int	Correct.	Go
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
[4, 24, 5	[4, 24, 5]	Close bracket.	Ruby
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
handle	handle()	Add parentheses.	Kotlin
let num: number = 'data';	let num: string = 'data';	Fix type.	TypeScript
<img src='world.jpg'>	<img src='world.jpg' alt='desc'>	Add alt text.	HTML

fmt.Println 'info'

fmt.Println('info')

Missing parentheses.

Go

let temp: i32 = "message";

let temp: &str = "message";

Type mismatch.

Rust

[x*x for x in data if x > 22]

Correct list comprehension.

Python

let foo = 'message'

let foo = "message"

Double quotes.

Swift

if (result = 81) {}

if (result == 81) {}

Use ==.

Dart

if (c = 8)

if (c == 8)

Use ==.

R

val index = 'output'

val index = "output"

Double quotes.

Kotlin

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

Correct.

Python

else print('world')

else: print('world')

Colon after else.

Python

switch(temp){{ case 8: break; }}

switch(temp){{ case 8: break; default: break; }}

Add default case.

Java

while read line; do echo $line; done < data.txt

Correct.

Shell

lambda x: x+1

Correct lambda.

Python

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

const obj:Person = {{name:'world', age:27}};

Add missing property.

TypeScript

x = test

x = 'test'

Quote strings.

Python

<?php // code ?>

Correct.

PHP

fn process() -> i32 {{ 40 }}

Correct.

Rust

for (x in data)

for (x of data)

for...in iterates keys.

JavaScript

'data' + 42

'data' + 42.to_s

Convert int.

Ruby

x := 26

Correct.

Go

WHERE email = '33'

WHERE email = 33

Don't quote integer.

SQL

.Item {{ color: #333; }}

Correct.

CSS

let msg = String::from("data"); let r=&msg; msg.push_str("!");

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

Cannot mutate while borrowed.

Rust

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

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

Type not in union.

TypeScript

def test(): print('test')

Indent function body.

Python

const http = require('http'); http.createServer((req,res) => res.end('info')).listen(11);

Correct.

Node.js

function handle(data:string){{return data;}} handle(82);

function handle(data:string){{return data;}} handle('test');

Pass correct type.

TypeScript

'value' + 96

'value' + str(96)

Can't add int to string.

Python

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

Correct.

Dart

let mut x=23; let ref1=&mut x; let r2=&mut x;

let mut x=23; {{ let ref1=&mut x; }} let r2=&mut x;

Only one mutable borrow.

Rust

String b = 'output';

String b = "output";

Double quotes.

Java

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

def compute puts 'value' end

Correct.

Ruby

print('world')

Correct.

R

def bar(foo): return foo + 1

Correct.

Python

{ "name": "result" }

Correct.

JSON

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

Correct.

CSS

val z = 71; z = 72

var z = 71; z = 72

Use var for reassignment.

Scala

match x {{ 1 => {{}} }}

match x {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

const c;

const c = 42;

Initialize const.

JavaScript

ArrayList list = new ArrayList();

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

Use generics.

Java

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

Correct.

PowerShell

items[85]

if items.indices.contains(85) {{ items[85] }}

Check index.

Swift

list: - item1 - item2

Correct.

YAML

if [ $val = 51 ]; then

if [ "$val" = 51 ]; then

Quote variable.

Shell

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

Correct.

MATLAB

[45, 17, 25

[45, 17, 25]

Close bracket.

Python

'42' + 100

42 + 100

Avoid string coercion.

JavaScript

Correct.

XML

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

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

Missing semicolon.

JavaScript

console.log('info'

console.log('info')

Close parenthesis.

JavaScript

disp('output')

Correct.

MATLAB

jwt.sign({{id:64}}, 'token');

jwt.sign({{id:64}}, 'token', {{expiresIn:'7d'}});

Add expiration.

Node.js

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

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

Arrow functions are cleaner.

JavaScript

Remove trailing comma.

JSON

UPDATE items SET email='world' WHERE role=98

UPDATE items SET email='world' WHERE role=98;

Add semicolon.

SQL

$arr[72]

if ($arr.Count -gt 72) {{ $arr[72] }}

Check bounds.

PowerShell

const b = 72; b = 41;

let b = 72; b = 41;

Cannot reassign const.

JavaScript

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

echo output hello

echo 'output hello'

Quote to prevent splitting.

Shell

List(82,13,30)

Correct.

Scala

$items[27] = 5;

if (isset($items[27])) $items[27] = 5;

Check existence.

PHP

let foo: number | null = null; foo.toFixed(5);

let foo: number | null = null; if(foo!==null) foo.toFixed(5);

Null check.

TypeScript

Add rel for security.

HTML

40foo = 10

foo40 = 10

Variable cannot start with digit.

Python

#content {{ color: blue; }}

Correct.

CSS

if bar = 56

if bar == 56

Use ==.

Ruby

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

<hr>

Self-closing.

HTML

z > 87 & a < 81

z > 87 and a < 81

Use 'and' not '&'.

Python

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

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

Initialize variable.

Java

item = 60

item=60

No spaces.

Shell

if (temp = 68) {{}}

if (temp == 68) {{}}

Use ==.

Java

DELETE FROM products WHERE id=3

DELETE FROM products WHERE id=3;

Add semicolon.

SQL

String name = 'hello';

Correct.

Dart

if num = 84

if num == 84

Use ==.

Go

Add alt text.

HTML

let bar = 13; let bar = 6;

let bar = 13; bar = 6;

Duplicate declaration.

JavaScript

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

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

Throw Error objects.

JavaScript

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

Correct.

Java

if b > 57 print('value')

if b > 57: print('value')

Colon missing after if.

Python

SELECT * FROM items WHRE email=89;

SELECT * FROM items WHERE email=89;

Fix WHERE.

SQL

var x = 15;

Correct.

Dart

let temp: i32 = "message";

let temp: &str = "message";

Type mismatch.

Rust

if y = 75:

if y == 75:

Use == for comparison.

Python

[48, 97, 16

[48, 97, 16]

Close bracket.

Python

Remove trailing comma.

JSON

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

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

Arrow functions are cleaner.

JavaScript

if ($x = 48)

if ($x == 48)

Use ==.

Perl

jwt.sign({{id:84}}, 'token');

jwt.sign({{id:84}}, 'token', {{expiresIn:'15m'}});

Add expiration.

Node.js

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

Correct.

MATLAB

Use CSS.

HTML

{ "name": "hello" }

Correct.

JSON

bar = 94

bar=94

No spaces.

Shell

var x int

Correct.

Go

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

Correct.

CSS

[4, 24, 5

[4, 24, 5]

Close bracket.

Ruby

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

handle

handle()

Add parentheses.

Kotlin

let num: number = 'data';

let num: string = 'data';

Fix type.

TypeScript

Add alt text.

HTML