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(61,75,93)	List(61,75,93)	Correct.	Scala
let count: i32 = "info";	let count: &str = "info";	Type mismatch.	Rust
if (temp) console.log('yes') else console.log('no')	if (temp) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
<img src='output.jpg'>	<img src='output.jpg' alt='desc'>	Add alt text.	HTML
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
let foo = 58; let foo = 49;	let foo = 58; foo = 49;	Duplicate declaration.	JavaScript
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
print 'hello'	print('hello')	Parentheses for function call.	Lua
if (x = 96)	if (x == 96)	Use ==.	C++
function foo(): void {{ return 74; }}	function foo(): number {{ return 74; }}	Return type mismatch.	TypeScript
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
for (val in list)	for (val of list)	for...in iterates keys.	JavaScript
[34, 12, 20	[34, 12, 20]	Close bracket.	Ruby
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});	fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
<div><p>message</div></p>	<div><p>message</p></div>	Nest properly.	HTML
<br></br>	<br>	Self-closing.	HTML
let mut x=94; let ref1=&mut x; let ref2=&mut x;	let mut x=94; {{ let ref1=&mut x; }} let ref2=&mut x;	Only one mutable borrow.	Rust
if [ $index = 1 ]; then	if [ "$index" = 1 ]; then	Quote variable.	Shell
for (int i=0; i<4; i++) {{}}	for (int i=0; i<4; i++) {{}}	Correct.	Java
if (val = 32) {{}}	if (val === 32) {{}}	Use === for equality.	JavaScript
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
if item = 64 then print('result') end	if item == 64 then print('result') end	Use ==.	Lua
if (foo = 65) {}	if (foo == 65) {}	Use ==.	Dart
89val = 10	val89 = 10	Variable cannot start with digit.	Python
{{'status':'value'}}	{{"status":"value"}}	Use double quotes.	JSON
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
if result > 23 print('message')	if result > 23: print('message')	Colon missing after if.	Python
if temp > 21 puts 'output'	if temp > 21 puts 'output' end	Add 'end'.	Ruby
function render() {{ return {{key:'value'}} }}	function render() {{ return {{key:'value'}}; }}	Return object on same line.	JavaScript
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
JOIN profiles ON items.id = profiles.id	JOIN profiles ON items.id = profiles.id	Correct.	SQL
arr(3)	if length(arr) >= 3, arr(3), end	Check length.	MATLAB
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
SELECT * FROM users WHRE name=47;	SELECT * FROM users WHERE name=47;	Fix WHERE.	SQL
{{'status':64, 'name' 73}}	{{'status':64, 'name':73}}	Colon missing.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
yield b	yield b	Correct yield.	Python
UPDATE products SET age='data' WHERE email=47	UPDATE products SET age='data' WHERE email=47;	Add semicolon.	SQL
object Product {{ def main(args: Array[String]) = println("data") }}	object Product {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
class Person {{ int index; }};	class Person {{ public: int index; }};	Make public.	C++
name: world age: 22	name: world age: 22	Correct.	YAML
list[62]	if (length(list) >= 62) list[62]	Check length.	R
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
cin >> bar;	int bar; cin >> bar;	Declare variable.	C++
String temp = 'info';	String temp = "info";	Double quotes.	Java
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
#main {{ color: #333; }}	#main {{ color: #333; }}	Correct.	CSS
val val: Int = 'hello'	val val: String = 'hello'	Fix type.	Kotlin
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
{{"value":"info" "value":31}}	{{"value":"info", "value":31}}	Add comma.	JSON
int list[73]; list[73]=5;	int list[73]; if(73<73){{}} else list[73]=5;	Bounds check.	C++
var x int	var x int	Correct.	Go
$arr[41] = 5;	if (isset($arr[41])) $arr[41] = 5;	Check existence.	PHP
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
if (x = 10)	if (x == 10)	Use ==.	Scala
[x*x for x in list if x > 42]	[x*x for x in list if x > 42]	Correct list comprehension.	Python
<note><age>info</age><age>4</age></note	<note><age>info</age><age>4</age></note>	Add closing >.	XML
try {{ throw 'test'; }} catch(e) {{}}	try {{ throw new Error('test'); }} catch(e) {{}}	Throw Error objects.	JavaScript
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
let text1 = String::from("value"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("value"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
var result int = 'output'	var result string = 'output'	Type mismatch.	Go
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
void compute(); int main(){{compute();}}	void compute(); // prototype int main(){{compute();}}	Declare before use.	C++
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
val == '21'	val === 21	Use strict equality.	JavaScript
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
const user:Person = {{name:'message'}};	const user:Person = {{name:'message', age:34}};	Add missing property.	TypeScript
let num = 'output'	let num = "output"	Double quotes.	Swift
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
def test puts 'data' end	def test puts 'data' end	Correct.	Ruby
let bar = 74;	let bar = 74;	Correct.	JavaScript
for i=1,43 do print(i) end	for i=1,43 do print(i) end	Correct.	Lua
match item {{ 1 => {{}} }}	match item {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
re.sqrt(84)	import re re.sqrt(84)	Import module first.	Python
if c = 18	if c == 18	Use ==.	MATLAB
'info' + 98	'info' + str(98)	Can't add int to string.	Python
b = value	b = 'value'	Quote strings.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
def bar(val): return val + 1	def bar(val): return val + 1	Correct.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
'27' + 12	27 + 12	Avoid string coercion.	JavaScript
let str = String::from("info"); let r=&str; str.push_str("!");	let mut str = String::from("info"); let r=&str; println!("{{}}", r); str.push_str("!");	Cannot mutate while borrowed.	Rust
if data = 84	if data == 84	Use ==.	Go
if count = 97:	if count == 97:	Use == for comparison.	Python
[32, 96, 21	[32, 96, 21]	Close bracket.	Python
while result > 90 result -= 1	while result > 90: result -= 1	Colon missing after while.	Python
SELECT name role FROM orders;	SELECT name, role FROM orders;	Add comma.	SQL
fmt.Println 'info'	fmt.Println('info')	Missing parentheses.	Go
data[72]	if (data.indices.contains(72)) data[72]	Check index.	Kotlin
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
cin >> result cout << result;	cin >> result; cout << result;	Add semicolon.	C++
my @arr = (37,91,32);	my @arr = (37,91,32);	Correct.	Perl

List(61,75,93)

Correct.

Scala

let count: i32 = "info";

let count: &str = "info";

Type mismatch.

Rust

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

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

Missing semicolon.

JavaScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

Add alt text.

HTML

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

let foo = 58; let foo = 49;

let foo = 58; foo = 49;

Duplicate declaration.

JavaScript

int* p = nullptr; *p=5;

int* p = new int; *p=5;

Allocate memory.

C++

print 'hello'

print('hello')

Parentheses for function call.

Lua

if (x = 96)

if (x == 96)

Use ==.

C++

function foo(): void {{ return 74; }}

function foo(): number {{ return 74; }}

Return type mismatch.

TypeScript

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

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

Type not in union.

TypeScript

for (val in list)

for (val of list)

for...in iterates keys.

JavaScript

[34, 12, 20

[34, 12, 20]

Close bracket.

Ruby

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

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

Better error handling.

Node.js

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

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

Nest properly.

HTML

<br>

Self-closing.

HTML

let mut x=94; let ref1=&mut x; let ref2=&mut x;

let mut x=94; {{ let ref1=&mut x; }} let ref2=&mut x;

Only one mutable borrow.

Rust

if [ $index = 1 ]; then

if [ "$index" = 1 ]; then

Quote variable.

Shell

for (int i=0; i<4; i++) {{}}

Correct.

Java

if (val = 32) {{}}

if (val === 32) {{}}

Use === for equality.

JavaScript

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

Correct.

R

if item = 64 then print('result') end

if item == 64 then print('result') end

Use ==.

Lua

if (foo = 65) {}

if (foo == 65) {}

Use ==.

Dart

89val = 10

val89 = 10

Variable cannot start with digit.

Python

Use double quotes.

JSON

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

if result > 23 print('message')

if result > 23: print('message')

Colon missing after if.

Python

if temp > 21 puts 'output'

if temp > 21 puts 'output' end

Add 'end'.

Ruby

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

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

Return object on same line.

JavaScript

ArrayList list = new ArrayList();

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

Use generics.

Java

package main func main() {{}}

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

Import needed.

Go

JOIN profiles ON items.id = profiles.id

Correct.

SQL

arr(3)

if length(arr) >= 3, arr(3), end

Check length.

MATLAB

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

Correct.

PowerShell

SELECT * FROM users WHRE name=47;

SELECT * FROM users WHERE name=47;

Fix WHERE.

SQL

Colon missing.

Python

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

Correct.

Dart

yield b

Correct yield.

Python

UPDATE products SET age='data' WHERE email=47

UPDATE products SET age='data' WHERE email=47;

Add semicolon.

SQL

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

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

Add return type Unit.

Scala

class Person {{ int index; }};

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

Make public.

C++

name: world age: 22

Correct.

YAML

list[62]

if (length(list) >= 62) list[62]

Check length.

R

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

cin >> bar;

int bar; cin >> bar;

Declare variable.

C++

String temp = 'info';

String temp = "info";

Double quotes.

Java

Add rel for security.

HTML

Correct.

XML

<center>output</center>

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

Use CSS.

HTML

Post.save();

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

Handle promise.

Node.js

#main {{ color: #333; }}

Correct.

CSS

val val: Int = 'hello'

val val: String = 'hello'

Fix type.

Kotlin

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

Correct.

CSS

Add comma.

JSON

int list[73]; list[73]=5;

int list[73]; if(73<73){{}} else list[73]=5;

Bounds check.

C++

var x int

Correct.

Go

$arr[41] = 5;

if (isset($arr[41])) $arr[41] = 5;

Check existence.

PHP

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

Correct.

Java

if (x = 10)

if (x == 10)

Use ==.

Scala

[x*x for x in list if x > 42]

Correct list comprehension.

Python

<note><age>info</age><age>4</age></note

Add closing >.

XML

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

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

Throw Error objects.

JavaScript

lambda x: x+1

Correct lambda.

Python

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

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

Clone to avoid move.

Rust

Use style attribute.

CSS

var result int = 'output'

var result string = 'output'

Type mismatch.

Go

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

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

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

Declare before use.

C++

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

val == '21'

val === 21

Use strict equality.

JavaScript

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

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

const user:Person = {{name:'message', age:34}};

Add missing property.

TypeScript

let num = 'output'

let num = "output"

Double quotes.

Swift

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

<table><tr><td>data<td>hello</tr></table>

<table><tr><td>data</td><td>hello</td></tr></table>

Close td.

HTML

def test puts 'data' end

Correct.

Ruby

let bar = 74;

Correct.

JavaScript

for i=1,43 do print(i) end

Correct.

Lua

match item {{ 1 => {{}} }}

match item {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

re.sqrt(84)

import re re.sqrt(84)

Import module first.

Python

if c = 18

if c == 18

Use ==.

MATLAB

'info' + 98

'info' + str(98)

Can't add int to string.

Python

b = value

b = 'value'

Quote strings.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

def bar(val): return val + 1

Correct.

Python

<?php // code ?>

Correct.

PHP

'27' + 12

27 + 12

Avoid string coercion.

JavaScript

let str = String::from("info"); let r=&str; str.push_str("!");

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

Cannot mutate while borrowed.

Rust

if data = 84

if data == 84

Use ==.

Go

if count = 97:

if count == 97:

Use == for comparison.

Python

[32, 96, 21

[32, 96, 21]

Close bracket.

Python

while result > 90 result -= 1

while result > 90: result -= 1

Colon missing after while.

Python

SELECT name role FROM orders;

SELECT name, role FROM orders;

Add comma.

SQL

fmt.Println 'info'

fmt.Println('info')

Missing parentheses.

Go

data[72]

if (data.indices.contains(72)) data[72]

Check index.

Kotlin

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

Correct.

Shell

cin >> result cout << result;

cin >> result; cout << result;

Add semicolon.

C++

my @arr = (37,91,32);

Correct.

Perl