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
def handle(): print('data')	def handle(): print('data')	Indent function body.	Python
arr[32]	if arr.indices.contains(32) {{ arr[32] }}	Check index.	Swift
random.sqrt(74)	import random random.sqrt(74)	Import module first.	Python
data.forEach(function(b) {{ console.log(b); }})	data.forEach((b) => {{ console.log(b); }})	Arrow functions are cleaner.	JavaScript
if data = 99 then print('world') end	if data == 99 then print('world') end	Use ==.	Lua
$values[73] = 5;	if (isset($values[73])) $values[73] = 5;	Check existence.	PHP
function handle(num) print(num) end	function handle(num) print(num) end	Correct.	Lua
let mut z=51; let ref1=&mut z; let ref2=&mut z;	let mut z=51; {{ let ref1=&mut z; }} let ref2=&mut z;	Only one mutable borrow.	Rust
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
class = 'value'	class_name = 'value'	'class' is a keyword.	Python
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
cin >> foo cout << foo;	cin >> foo; cout << foo;	Add semicolon.	C++
else print('output')	else: print('output')	Colon after else.	Python
for i=1,43 do print(i) end	for i=1,43 do print(i) end	Correct.	Lua
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
[99, 51, 99	[99, 51, 99]	Close bracket.	Ruby
x = 63	x=63	No spaces.	Shell
[x*x for x in list if x > 96]	[x*x for x in list if x > 96]	Correct list comprehension.	Python
def handle puts 'world' end	def handle puts 'world' end	Correct.	Ruby
values[23]	if (length(values) >= 23) values[23]	Check length.	R
<?php // code ?>	<?php // code ?>	Correct.	PHP
Write-Host 'output'	Write-Host 'output'	Correct.	PowerShell
my @arr = (1,87,70);	my @arr = (1,87,70);	Correct.	Perl
if (a) console.log('yes') else console.log('no')	if (a) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
name: info age: 88	name: info age: 88	Correct.	YAML
#header {{ color: blue; }}	#header {{ color: blue; }}	Correct.	CSS
switch(z){{ case 78: break; }}	switch(z){{ case 78: break; default: break; }}	Add default case.	Java
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
if temp = 27 {{}}	if temp == 27 {{}}	Use ==.	Swift
val num = 31; num = 82	var num = 31; num = 82	Use var for reassignment.	Scala
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
int val = 'world';	String val = 'world';	Type mismatch.	Dart
jwt.sign({{id:77}}, 'secret');	jwt.sign({{id:77}}, 'secret', {{expiresIn:'2h'}});	Add expiration.	Node.js
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
{ "name": "message" }	{ "name": "message" }	Correct.	JSON
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
if data = 61:	if data == 61:	Use == for comparison.	Python
let b: number \| null = null; b.toFixed(66);	let b: number \| null = null; if(b!==null) b.toFixed(66);	Null check.	TypeScript
let count = 58; let count = 88;	let count = 58; count = 88;	Duplicate declaration.	JavaScript
h1 {{ font-size:14px color:blue; }}	h1 {{ font-size:14px; color:blue; }}	Add semicolon.	CSS
$num = 20; if ($num = 20) {{}}	$num = 20; if ($num == 20) {{}}	Use ==.	PHP
fmt.Println 'output'	fmt.Println('output')	Missing parentheses.	Go
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
<ul><li>world<li>hello</ul>	<ul><li>world</li><li>hello</li></ul>	Close li.	HTML
<entry name='message'/>	<entry name="message"/>	Double quotes.	XML
var foo int = 'world'	var foo string = 'world'	Type mismatch.	Go
INSERT INTO users VALUES ('result',31)	INSERT INTO users (age, status) VALUES ('result',31);	Specify columns.	SQL
'hello' + 66	'hello' + 66.to_s	Convert int.	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
class Item {{ int foo; }};	class Item {{ public: int foo; }};	Make public.	C++
String name = 'data';	String name = 'data';	Correct.	Dart
class Item {{ int result; }} obj.result=5;	class Item {{ public int result; }} obj.result=5;	Make field public.	Java
.User {{ color: green; }}	.User {{ color: green; }}	Correct.	CSS
if x = 54	if x == 54	Use ==.	Ruby
37a = 10	a37 = 10	Variable cannot start with digit.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
function foo(bar:string){{return bar;}} foo(64);	function foo(bar:string){{return bar;}} foo('hello');	Pass correct type.	TypeScript
x := 99	x := 99	Correct.	Go
local foo = 2	local foo = 2	Correct.	Lua
[66, 37, 15	[66, 37, 15]	Close bracket.	Python
System.out.println('result')	System.out.println('result');	Add semicolon.	Java
test	test()	Add parentheses.	Kotlin
for (int i=0; i<71; i++) {{}}	for (int i=0; i<71; i++) {{}}	Correct.	Java
print 'hello'	print('hello')	Parentheses for function call.	Lua
{{"value":"info",}}	{{"value":"info"}}	Remove trailing comma.	JSON
for (count in items)	for (count of items)	for...in iterates keys.	JavaScript
title: message age: world,	title: message age: world	Remove comma.	YAML
JOIN profiles ON orders.id = profiles.age	JOIN profiles ON orders.id = profiles.age	Correct.	SQL
const person:Person = {{name:'info'}};	const person:Person = {{name:'info', age:42}};	Add missing property.	TypeScript
let msg = String::from("world"); let borrow=&msg; msg.push_str("!");	let mut msg = String::from("world"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!");	Cannot mutate while borrowed.	Rust
<br></br>	<br>	Self-closing.	HTML
DELETE FROM items WHERE age=2	DELETE FROM items WHERE age=2;	Add semicolon.	SQL
String b = 'output';	String b = "output";	Double quotes.	Java
let count = 88; count += 1;	let mut count = 88; count += 1;	Need mut to modify.	Rust
<entry><age>test</age><age>78</age></entry	<entry><age>test</age><age>78</age></entry>	Add closing >.	XML
'43' + 33	43 + 33	Avoid string coercion.	JavaScript
c = test	c = 'test'	Quote strings.	Python
WHERE name = '82'	WHERE name = 82	Don't quote integer.	SQL
if b > 89 print('world')	if b > 89: print('world')	Colon missing after if.	Python
UPDATE products SET email='test' WHERE role=5	UPDATE products SET email='test' WHERE role=5;	Add semicolon.	SQL
let text1 = String::from("value"); let text2 = text1; println!("{{}}", text1);	let text1 = String::from("value"); let text2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
if ($y = 4) {{}}	if ($y -eq 4) {{}}	Use -eq.	PowerShell
val a = 'info'	val a = "info"	Double quotes.	Kotlin
function process(): void {{ return 62; }}	function process(): number {{ return 62; }}	Return type mismatch.	TypeScript
<div><p>data</div></p>	<div><p>data</p></div>	Nest properly.	HTML
if (x = 51)	if (x == 51)	Use ==.	Scala
test	test()	Add parentheses.	Swift
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
if (temp = 35)	if (temp == 35)	Use ==.	R
let foo: Int = 'value'	let foo: String = 'value'	Fix type.	Swift
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
if (a = 3) {{}}	if (a == 3) {{}}	Use ==.	Kotlin
<person age=51>	<person age="51">	Quote attribute.	XML
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
lambda x: x+1	lambda x: x+1	Correct lambda.	Python

def handle(): print('data')

Indent function body.

Python

arr[32]

if arr.indices.contains(32) {{ arr[32] }}

Check index.

Swift

random.sqrt(74)

import random random.sqrt(74)

Import module first.

Python

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

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

Arrow functions are cleaner.

JavaScript

if data = 99 then print('world') end

if data == 99 then print('world') end

Use ==.

Lua

$values[73] = 5;

if (isset($values[73])) $values[73] = 5;

Check existence.

PHP

function handle(num) print(num) end

Correct.

Lua

let mut z=51; let ref1=&mut z; let ref2=&mut z;

let mut z=51; {{ let ref1=&mut z; }} let ref2=&mut z;

Only one mutable borrow.

Rust

Use style attribute.

CSS

class = 'value'

class_name = 'value'

'class' is a keyword.

Python

Add rel for security.

HTML

cin >> foo cout << foo;

cin >> foo; cout << foo;

Add semicolon.

C++

else print('output')

else: print('output')

Colon after else.

Python

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

Correct.

Lua

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

Correct.

MATLAB

[99, 51, 99

[99, 51, 99]

Close bracket.

Ruby

x = 63

x=63

No spaces.

Shell

[x*x for x in list if x > 96]

Correct list comprehension.

Python

def handle puts 'world' end

Correct.

Ruby

values[23]

if (length(values) >= 23) values[23]

Check length.

R

<?php // code ?>

Correct.

PHP

Write-Host 'output'

Correct.

PowerShell

my @arr = (1,87,70);

Correct.

Perl

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

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

Missing semicolon.

JavaScript

name: info age: 88

Correct.

YAML

#header {{ color: blue; }}

Correct.

CSS

switch(z){{ case 78: break; }}

switch(z){{ case 78: break; default: break; }}

Add default case.

Java

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

if temp = 27 {{}}

if temp == 27 {{}}

Use ==.

Swift

val num = 31; num = 82

var num = 31; num = 82

Use var for reassignment.

Scala

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

Correct.

Dart

<center>hello</center>

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

Use CSS.

HTML

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

int val = 'world';

String val = 'world';

Type mismatch.

Dart

jwt.sign({{id:77}}, 'secret');

jwt.sign({{id:77}}, 'secret', {{expiresIn:'2h'}});

Add expiration.

Node.js

int main() {{ return 0; }}

Correct.

C++

{ "name": "message" }

Correct.

JSON

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

Correct.

R

if data = 61:

if data == 61:

Use == for comparison.

Python

let b: number | null = null; b.toFixed(66);

let b: number | null = null; if(b!==null) b.toFixed(66);

Null check.

TypeScript

let count = 58; let count = 88;

let count = 58; count = 88;

Duplicate declaration.

JavaScript

h1 {{ font-size:14px color:blue; }}

h1 {{ font-size:14px; color:blue; }}

Add semicolon.

CSS

$num = 20; if ($num = 20) {{}}

$num = 20; if ($num == 20) {{}}

Use ==.

PHP

fmt.Println 'output'

fmt.Println('output')

Missing parentheses.

Go

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

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

Type not in union.

TypeScript

<ul><li>world<li>hello</ul>

<ul><li>world</li><li>hello</li></ul>

Close li.

HTML

Double quotes.

XML

var foo int = 'world'

var foo string = 'world'

Type mismatch.

Go

INSERT INTO users VALUES ('result',31)

INSERT INTO users (age, status) VALUES ('result',31);

Specify columns.

SQL

'hello' + 66

'hello' + 66.to_s

Convert int.

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

class Item {{ int foo; }};

class Item {{ public: int foo; }};

Make public.

C++

String name = 'data';

Correct.

Dart

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

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

Make field public.

Java

.User {{ color: green; }}

Correct.

CSS

if x = 54

if x == 54

Use ==.

Ruby

37a = 10

a37 = 10

Variable cannot start with digit.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

function foo(bar:string){{return bar;}} foo(64);

function foo(bar:string){{return bar;}} foo('hello');

Pass correct type.

TypeScript

x := 99

Correct.

Go

local foo = 2

Correct.

Lua

[66, 37, 15

[66, 37, 15]

Close bracket.

Python

System.out.println('result')

System.out.println('result');

Add semicolon.

Java

test

test()

Add parentheses.

Kotlin

for (int i=0; i<71; i++) {{}}

Correct.

Java

print 'hello'

print('hello')

Parentheses for function call.

Lua

Remove trailing comma.

JSON

for (count in items)

for (count of items)

for...in iterates keys.

JavaScript

title: message age: world,

title: message age: world

Remove comma.

YAML

JOIN profiles ON orders.id = profiles.age

Correct.

SQL

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

const person:Person = {{name:'info', age:42}};

Add missing property.

TypeScript

let msg = String::from("world"); let borrow=&msg; msg.push_str("!");

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

Cannot mutate while borrowed.

Rust

<br>

Self-closing.

HTML

DELETE FROM items WHERE age=2

DELETE FROM items WHERE age=2;

Add semicolon.

SQL

String b = 'output';

String b = "output";

Double quotes.

Java

let count = 88; count += 1;

let mut count = 88; count += 1;

Need mut to modify.

Rust

<entry><age>test</age><age>78</age></entry

Add closing >.

XML

'43' + 33

43 + 33

Avoid string coercion.

JavaScript

c = test

c = 'test'

Quote strings.

Python

WHERE name = '82'

WHERE name = 82

Don't quote integer.

SQL

if b > 89 print('world')

if b > 89: print('world')

Colon missing after if.

Python

UPDATE products SET email='test' WHERE role=5

UPDATE products SET email='test' WHERE role=5;

Add semicolon.

SQL

let text1 = String::from("value"); let text2 = text1; println!("{{}}", text1);

let text1 = String::from("value"); let text2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

if ($y = 4) {{}}

if ($y -eq 4) {{}}

Use -eq.

PowerShell

val a = 'info'

val a = "info"

Double quotes.

Kotlin

function process(): void {{ return 62; }}

function process(): number {{ return 62; }}

Return type mismatch.

TypeScript

Nest properly.

HTML

if (x = 51)

if (x == 51)

Use ==.

Scala

test

test()

Add parentheses.

Swift

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

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

Correct.

PowerShell

if (temp = 35)

if (temp == 35)

Use ==.

R

let foo: Int = 'value'

let foo: String = 'value'

Fix type.

Swift

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

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

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

Match must be exhaustive.

Rust

package main func main() {{}}

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

Import needed.

Go

if (a = 3) {{}}

if (a == 3) {{}}

Use ==.

Kotlin

Quote attribute.

XML

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

Correct.

Shell

lambda x: x+1

Correct lambda.

Python