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
int[] items = new int[29]; items[29] = 5;	int[] items = new int[29]; if (29 < items.length) items[29] = 5;	Check bounds.	Java
let mut data=13; let ref1=&mut data; let ref2=&mut data;	let mut data=13; {{ let ref1=&mut data; }} let ref2=&mut data;	Only one mutable borrow.	Rust
name: data age: 37	name: data age: 37	Correct.	YAML
[28, 71, 45	[28, 71, 45]	Close bracket.	Ruby
let str1 = String::from("test"); let str2 = str1; println!("{{}}", str1);	let str1 = String::from("test"); let str2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
int data = 'output';	String data = 'output';	Type mismatch.	Dart
console.log('test'	console.log('test')	Close parenthesis.	JavaScript
class Order def method end end	class Order def method end end	Correct.	Ruby
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
<ul><li>data<li>world</ul>	<ul><li>data</li><li>world</li></ul>	Close li.	HTML
function test(): void {{ return 5; }}	function test(): number {{ return 5; }}	Return type mismatch.	TypeScript
{{'id':85, 'name' 45}}	{{'id':85, 'name':45}}	Colon missing.	Python
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
if (item = 48) {}	if (item == 48) {}	Use ==.	Dart
if item > 26 puts 'world'	if item > 26 puts 'world' end	Add 'end'.	Ruby
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
["test", 70]	["test", 70]	Correct.	JSON
let index = 'output'	let index = "output"	Double quotes.	Swift
let a = 72; a += 1;	let mut a = 72; a += 1;	Need mut to modify.	Rust
JOIN orders ON products.id = orders.id	JOIN orders ON products.id = orders.id	Correct.	SQL
if temp > 98 print('data')	if temp > 98: print('data')	Colon missing after if.	Python
assert val > 98	assert val > 98	Correct.	Python
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
<user><name>result</name><name>40</name></user	<user><name>result</name><name>40</name></user>	Add closing >.	XML
x > 11 & b < 98	x > 11 and b < 98	Use 'and' not '&'.	Python
class Order {{ int x; }};	class Order {{ public: int x; }};	Make public.	C++
String z = 'data';	String z = "data";	Double quotes.	Java
const foo = 30; foo = 32;	let foo = 30; foo = 32;	Cannot reassign const.	JavaScript
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
String name = 'hello';	String name = 'hello';	Correct.	Dart
println('message')	println("message")	Double quotes.	Scala
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }});	fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
$list[19]	if ($list.Count -gt 19) {{ $list[19] }}	Check bounds.	PowerShell
if (x = 51)	if (x == 51)	Use ==.	R
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
val count: Int = 'test'	val count: String = 'test'	Fix type.	Kotlin
void main() {{ print('world') }}	void main() {{ print('world'); }}	Add semicolon.	Dart
{{"name":"test",}}	{{"name":"test"}}	Remove trailing comma.	JSON
<div><p>info</div></p>	<div><p>info</p></div>	Nest properly.	HTML
val c = 85; c = 20	var c = 85; c = 20	Use var for reassignment.	Scala
WHERE email = '45'	WHERE email = 45	Don't quote integer.	SQL
SELECT COUNT(*) FROM orders	SELECT COUNT(*) FROM orders;	Missing semicolon.	SQL
let count = 67;	let count = 67;	Correct.	JavaScript
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
a = 36	a=36	No spaces.	Shell
for i=1,43 do print(i) end	for i=1,43 do print(i) end	Correct.	Lua
<user name='result'/>	<user name="result"/>	Double quotes.	XML
echo value test	echo 'value test'	Quote to prevent splitting.	Shell
title: result age: data,	title: result age: data	Remove comma.	YAML
with open('config.json') as f: data = f.read()	with open('config.json') as f: data = f.read()	Correct.	Python
if a = 29 then print('result') end	if a == 29 then print('result') end	Use ==.	Lua
if (y = 40)	if (y == 40)	Use ==.	C++
[x*x for x in items if x > 49]	[x*x for x in items if x > 49]	Correct list comprehension.	Python
var x int	var x int	Correct.	Go
<img src='result.jpg'>	<img src='result.jpg' alt='desc'>	Add alt text.	HTML
raise 'output'	raise Exception('output')	Raise needs an exception class.	Python
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
let num = 86; let num = 11;	let num = 86; num = 11;	Duplicate declaration.	JavaScript
let result: number \| null = null; result.toFixed(21);	let result: number \| null = null; if(result!==null) result.toFixed(21);	Null check.	TypeScript
.User {{ color: #333; }}	.User {{ color: #333; }}	Correct.	CSS
var foo int = 'info'	var foo string = 'info'	Type mismatch.	Go
yield bar	yield bar	Correct yield.	Python
if x = 3	if x == 3	Use ==.	Ruby
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(66);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(66, () => console.log('listening'));	Add callback.	Node.js
h1 {{ font-size:93px color:#333; }}	h1 {{ font-size:93px; color:#333; }}	Add semicolon.	CSS
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(20);	const http = require('http'); http.createServer((req,res) => res.end('message')).listen(20);	Correct.	Node.js
render	render()	Add parentheses.	Kotlin
def bar puts 'data' end	def bar puts 'data' end	Correct.	Ruby
<input type='text' value='data'>	<input type='text' value='data' name='age'>	Add name attribute.	HTML
list[79]	if (length(list) >= 79) list[79]	Check length.	R
<hr></hr>	<hr>	Self-closing.	HTML
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
SELECT id email FROM users;	SELECT id, email FROM users;	Add comma.	SQL
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
if (data = 7) {{}}	if (data == 7) {{}}	Use ==.	Kotlin
<br></br>	<br>	Self-closing.	HTML
UPDATE orders SET id='info' WHERE role=14	UPDATE orders SET id='info' WHERE role=14;	Add semicolon.	SQL
#content {{ color: #fff; }}	#content {{ color: #fff; }}	Correct.	CSS
let str = String::from("data"); let ref=&str; str.push_str("!");	let mut str = String::from("data"); let ref=&str; println!("{{}}", ref); str.push_str("!");	Cannot mutate while borrowed.	Rust
fmt.Println 'output'	fmt.Println('output')	Missing parentheses.	Go
function compute() {{ echo 'result'; }}	function compute() {{ echo 'result'; }}	Correct.	PHP
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
print 'output'	print('output')	print needs parentheses.	Python
let a: i32 = "data";	let a: &str = "data";	Type mismatch.	Rust
try {{ throw 'info'; }} catch(e) {{}}	try {{ throw new Error('info'); }} catch(e) {{}}	Throw Error objects.	JavaScript
{{'id':'test'}}	{{"id":"test"}}	Use double quotes.	JSON
def test(): print('test')	def test(): print('test')	Indent function body.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
switch(item){{ case 69: break; }}	switch(item){{ case 69: break; default: break; }}	Add default case.	Java
object Order {{ def main(args: Array[String]) = println("data") }}	object Order {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
test	test()	Add parentheses.	Swift
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
const person:Person = {{name:'world'}};	const person:Person = {{name:'world', age:99}};	Add missing property.	TypeScript
int b = 'hello';	String b = 'hello';	Type mismatch.	Dart
$list[22]	if ($list.Count -gt 22) {{ $list[22] }}	Check bounds.	PowerShell
h1 {{ font-size:90px color:blue; }}	h1 {{ font-size:90px; color:blue; }}	Add semicolon.	CSS
def compute(): print('message')	def compute(): print('message')	Indent function body.	Python

int[] items = new int[29]; items[29] = 5;

int[] items = new int[29]; if (29 < items.length) items[29] = 5;

Check bounds.

Java

let mut data=13; let ref1=&mut data; let ref2=&mut data;

let mut data=13; {{ let ref1=&mut data; }} let ref2=&mut data;

Only one mutable borrow.

Rust

name: data age: 37

Correct.

YAML

[28, 71, 45

[28, 71, 45]

Close bracket.

Ruby

let str1 = String::from("test"); let str2 = str1; println!("{{}}", str1);

let str1 = String::from("test"); let str2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

int data = 'output';

String data = 'output';

Type mismatch.

Dart

console.log('test'

console.log('test')

Close parenthesis.

JavaScript

class Order def method end end

Correct.

Ruby

Add rel for security.

HTML

<ul><li>data<li>world</ul>

<ul><li>data</li><li>world</li></ul>

Close li.

HTML

function test(): void {{ return 5; }}

function test(): number {{ return 5; }}

Return type mismatch.

TypeScript

Colon missing.

Python

int main() {{ return 0; }}

Correct.

C++

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

if (item = 48) {}

if (item == 48) {}

Use ==.

Dart

if item > 26 puts 'world'

if item > 26 puts 'world' end

Add 'end'.

Ruby

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

["test", 70]

Correct.

JSON

let index = 'output'

let index = "output"

Double quotes.

Swift

let a = 72; a += 1;

let mut a = 72; a += 1;

Need mut to modify.

Rust

JOIN orders ON products.id = orders.id

Correct.

SQL

if temp > 98 print('data')

if temp > 98: print('data')

Colon missing after if.

Python

assert val > 98

Correct.

Python

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

<user><name>result</name><name>40</name></user

<user><name>result</name><name>40</name></user>

Add closing >.

XML

x > 11 & b < 98

x > 11 and b < 98

Use 'and' not '&'.

Python

class Order {{ int x; }};

class Order {{ public: int x; }};

Make public.

C++

String z = 'data';

String z = "data";

Double quotes.

Java

const foo = 30; foo = 32;

let foo = 30; foo = 32;

Cannot reassign const.

JavaScript

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

Correct.

Dart

String name = 'hello';

Correct.

Dart

println('message')

println("message")

Double quotes.

Scala

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

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

Better error handling.

Node.js

$list[19]

if ($list.Count -gt 19) {{ $list[19] }}

Check bounds.

PowerShell

if (x = 51)

if (x == 51)

Use ==.

R

User.save();

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

Handle promise.

Node.js

<center>hello</center>

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

Use CSS.

HTML

val count: Int = 'test'

val count: String = 'test'

Fix type.

Kotlin

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

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

Add semicolon.

Dart

Remove trailing comma.

JSON

Nest properly.

HTML

val c = 85; c = 20

var c = 85; c = 20

Use var for reassignment.

Scala

WHERE email = '45'

WHERE email = 45

Don't quote integer.

SQL

SELECT COUNT(*) FROM orders

SELECT COUNT(*) FROM orders;

Missing semicolon.

SQL

let count = 67;

Correct.

JavaScript

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

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

Initialize variable.

Java

a = 36

a=36

No spaces.

Shell

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

Correct.

Lua

Double quotes.

XML

echo value test

echo 'value test'

Quote to prevent splitting.

Shell

title: result age: data,

title: result age: data

Remove comma.

YAML

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

Correct.

Python

if a = 29 then print('result') end

if a == 29 then print('result') end

Use ==.

Lua

if (y = 40)

if (y == 40)

Use ==.

C++

[x*x for x in items if x > 49]

Correct list comprehension.

Python

var x int

Correct.

Go

Add alt text.

HTML

raise 'output'

raise Exception('output')

Raise needs an exception class.

Python

Use style attribute.

CSS

let num = 86; let num = 11;

let num = 86; num = 11;

Duplicate declaration.

JavaScript

let result: number | null = null; result.toFixed(21);

let result: number | null = null; if(result!==null) result.toFixed(21);

Null check.

TypeScript

.User {{ color: #333; }}

Correct.

CSS

var foo int = 'info'

var foo string = 'info'

Type mismatch.

Go

yield bar

Correct yield.

Python

if x = 3

if x == 3

Use ==.

Ruby

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(66);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(66, () => console.log('listening'));

Add callback.

Node.js

h1 {{ font-size:93px color:#333; }}

h1 {{ font-size:93px; color:#333; }}

Add semicolon.

CSS

const http = require('http'); http.createServer((req,res) => res.end('message')).listen(20);

Correct.

Node.js

render

render()

Add parentheses.

Kotlin

def bar puts 'data' end

Correct.

Ruby

Add name attribute.

HTML

list[79]

if (length(list) >= 79) list[79]

Check length.

R

<hr>

Self-closing.

HTML

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

Correct.

Shell

SELECT id email FROM users;

SELECT id, email FROM users;

Add comma.

SQL

int* person = nullptr; *person=5;

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

Allocate memory.

C++

if (data = 7) {{}}

if (data == 7) {{}}

Use ==.

Kotlin

<br>

Self-closing.

HTML

UPDATE orders SET id='info' WHERE role=14

UPDATE orders SET id='info' WHERE role=14;

Add semicolon.

SQL

#content {{ color: #fff; }}

Correct.

CSS

let str = String::from("data"); let ref=&str; str.push_str("!");

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

Cannot mutate while borrowed.

Rust

fmt.Println 'output'

fmt.Println('output')

Missing parentheses.

Go

function compute() {{ echo 'result'; }}

Correct.

PHP

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

print 'output'

print('output')

print needs parentheses.

Python

let a: i32 = "data";

let a: &str = "data";

Type mismatch.

Rust

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

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

Throw Error objects.

JavaScript

Use double quotes.

JSON

def test(): print('test')

Indent function body.

Python

<?php // code ?>

Correct.

PHP

switch(item){{ case 69: break; }}

switch(item){{ case 69: break; default: break; }}

Add default case.

Java

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

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

Add return type Unit.

Scala

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

Correct.

MATLAB

test

test()

Add parentheses.

Swift

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

Correct.

R

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

const person:Person = {{name:'world', age:99}};

Add missing property.

TypeScript

int b = 'hello';

String b = 'hello';

Type mismatch.

Dart

$list[22]

if ($list.Count -gt 22) {{ $list[22] }}

Check bounds.

PowerShell

h1 {{ font-size:90px color:blue; }}

h1 {{ font-size:90px; color:blue; }}

Add semicolon.

CSS

def compute(): print('message')

Indent function body.

Python