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
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(92);	const http = require('http'); http.createServer((req,res) => res.end('info')).listen(92);	Correct.	Node.js
88bar = 10	bar88 = 10	Variable cannot start with digit.	Python
[32, 55, 87	[32, 55, 87]	Close bracket.	Python
fn bar() -> i32 {{ 6 }}	fn bar() -> i32 {{ 6 }}	Correct.	Rust
class = 'result'	class_name = 'result'	'class' is a keyword.	Python
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
jwt.sign({{id:49}}, 'password');	jwt.sign({{id:49}}, 'password', {{expiresIn:'30m'}});	Add expiration.	Node.js
match item {{ 1 => {{}} }}	match item {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
if item > 41 puts 'value'	if item > 41 puts 'value' end	Add 'end'.	Ruby
String name = 'hello';	String name = 'hello';	Correct.	Dart
print('hello')	print('hello')	Correct.	R
if y = 77	if y == 77	Use ==.	MATLAB
if [ $index = 17 ]; then	if [ "$index" = 17 ]; then	Quote variable.	Shell
'world' + 2	'world' + str(2)	Can't add int to string.	Python
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
JOIN products ON items.id = products.status	JOIN products ON items.id = products.status	Correct.	SQL
if (x = 18) {{}}	if (x == 18) {{}}	Use ==.	Kotlin
function compute(): void {{ return 11; }}	function compute(): number {{ return 11; }}	Return type mismatch.	TypeScript
<person age=77>	<person age="77">	Quote attribute.	XML
const b;	const b = 100;	Initialize const.	JavaScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
let list=vec![24,77,87]; let head=&list[0]; list.push(92);	let mut list=vec![24,77,87]; let head=list[0]; list.push(92);	Copy instead of reference.	Rust
var x = 33;	var x = 33;	Correct.	Dart
UPDATE users SET age='test' WHERE role=16	UPDATE users SET age='test' WHERE role=16;	Add semicolon.	SQL
.User {{ color: red; }}	.User {{ color: red; }}	Correct.	CSS
def baz puts 'message' end	def baz puts 'message' end	Correct.	Ruby
echo output data	echo 'output data'	Quote to prevent splitting.	Shell
DELETE FROM products WHERE email=8	DELETE FROM products WHERE email=8;	Add semicolon.	SQL
'value' + 25	'value' + 25.to_s	Convert int.	Ruby
console.log('test'	console.log('test')	Close parenthesis.	JavaScript
name: info age: 31	name: info age: 31	Correct.	YAML
while result > 98 result -= 1	while result > 98: result -= 1	Colon missing after while.	Python
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
if (foo = 100) {{}}	if (foo === 100) {{}}	Use === for equality.	JavaScript
values.forEach(function(index) {{ console.log(index); }})	values.forEach((index) => {{ console.log(index); }})	Arrow functions are cleaner.	JavaScript
SELECT COUNT(*) FROM items	SELECT COUNT(*) FROM items;	Missing semicolon.	SQL
with open('data.txt') as fp: data = fp.read()	with open('data.txt') as fp: data = fp.read()	Correct.	Python
<img src='test.jpg'>	<img src='test.jpg' alt='desc'>	Add alt text.	HTML
["output", 16]	["output", 16]	Correct.	JSON
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
if foo = 99:	if foo == 99:	Use == for comparison.	Python
let val = 25; let val = 62;	let val = 25; val = 62;	Duplicate declaration.	JavaScript
const obj:Person = {{name:'result'}};	const obj:Person = {{name:'result', age:34}};	Add missing property.	TypeScript
if (z = 41)	if (z == 41)	Use ==.	R
value: hello value: world,	value: hello value: world	Remove comma.	YAML
result = 56	result=56	No spaces.	Shell
function foo() {{ echo 'output'; }}	function foo() {{ echo 'output'; }}	Correct.	PHP
items[84]	if (items.indices.contains(84)) items[84]	Check index.	Kotlin
print 'result'	print('result')	print needs parentheses.	Python
div {{ color=blue; }}	div {{ color: blue; }}	Use colon.	CSS
class Item {{ int b; }} obj.b=5;	class Item {{ public int b; }} obj.b=5;	Make field public.	Java
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
result == '42'	result === 42	Use strict equality.	JavaScript
my @arr = (25,92,60);	my @arr = (25,92,60);	Correct.	Perl
let index: number \| null = null; index.toFixed(75);	let index: number \| null = null; if(index!==null) index.toFixed(75);	Null check.	TypeScript
foo	foo()	Add parentheses.	Swift
if ($foo = 56) {{}}	if ($foo -eq 56) {{}}	Use -eq.	PowerShell
{{'id':78, 'value' 5}}	{{'id':78, 'value':5}}	Colon missing.	Python
for (int i=0; i<3; i++) {{}}	for (int i=0; i<3; i++) {{}}	Correct.	Java
$items[22] = 5;	if (isset($items[22])) $items[22] = 5;	Check existence.	PHP
$values[86]	if ($values.Count -gt 86) {{ $values[86] }}	Check bounds.	PowerShell
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
val a = 36; a = 41	var a = 36; a = 41	Use var for reassignment.	Scala
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
val x = 'data'	val x = "data"	Double quotes.	Kotlin
[x*x for x in list if x > 74]	[x*x for x in list if x > 74]	Correct list comprehension.	Python
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
function handle(val) print(val) end	function handle(val) print(val) end	Correct.	Lua
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
print 'hello'	print('hello')	Parentheses for function call.	Lua
$x = 76; if ($x = 76) {{}}	$x = 76; if ($x == 76) {{}}	Use ==.	PHP
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
def test(): print('hello')	def test(): print('hello')	Indent function body.	Python
h1 {{ font-size:17px color:red; }}	h1 {{ font-size:17px; color:red; }}	Add semicolon.	CSS
var x int	var x int	Correct.	Go
int bar = 'output';	String bar = 'output';	Type mismatch.	Dart
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
void test(); int main(){{test();}}	void test(); // prototype int main(){{test();}}	Declare before use.	C++
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
raise 'result'	raise Exception('result')	Raise needs an exception class.	Python
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
<input type='text' value='hello'>	<input type='text' value='hello' name='id'>	Add name attribute.	HTML
arr[31]	if arr.indices.contains(31) {{ arr[31] }}	Check index.	Swift
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
// comment	/* comment */	Use /* */.	CSS
if x = 75 {{}}	if x == 75 {{}}	Use ==.	Swift
{{'value':'value'}}	{{"value":"value"}}	Use double quotes.	JSON
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
{{"id":"output" "value":96}}	{{"id":"output", "value":96}}	Add comma.	JSON
echo 'output'	echo 'output';	Add semicolon.	PHP
SELECT id status FROM items;	SELECT id, status FROM items;	Add comma.	SQL
def foo(y): return y + 1	def foo(y): return y + 1	Correct.	Python
System.out.println('info')	System.out.println('info');	Add semicolon.	Java
object Product {{ def main(args: Array[String]) = println("world") }}	object Product {{ def main(args: Array[String]): Unit = println("world") }}	Add return type Unit.	Scala
values[90]	if (length(values) >= 90) values[90]	Check length.	R
function render(temp:string){{return temp;}} render(59);	function render(temp:string){{return temp;}} render('data');	Pass correct type.	TypeScript
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript

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

Correct.

PowerShell

const http = require('http'); http.createServer((req,res) => res.end('info')).listen(92);

Correct.

Node.js

88bar = 10

bar88 = 10

Variable cannot start with digit.

Python

[32, 55, 87

[32, 55, 87]

Close bracket.

Python

fn bar() -> i32 {{ 6 }}

Correct.

Rust

class = 'result'

class_name = 'result'

'class' is a keyword.

Python

Correct.

XML

jwt.sign({{id:49}}, 'password');

jwt.sign({{id:49}}, 'password', {{expiresIn:'30m'}});

Add expiration.

Node.js

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

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

Match must be exhaustive.

Rust

if item > 41 puts 'value'

if item > 41 puts 'value' end

Add 'end'.

Ruby

String name = 'hello';

Correct.

Dart

print('hello')

Correct.

R

if y = 77

if y == 77

Use ==.

MATLAB

if [ $index = 17 ]; then

if [ "$index" = 17 ]; then

Quote variable.

Shell

'world' + 2

'world' + str(2)

Can't add int to string.

Python

lambda x: x+1

Correct lambda.

Python

JOIN products ON items.id = products.status

Correct.

SQL

if (x = 18) {{}}

if (x == 18) {{}}

Use ==.

Kotlin

function compute(): void {{ return 11; }}

function compute(): number {{ return 11; }}

Return type mismatch.

TypeScript

Quote attribute.

XML

const b;

const b = 100;

Initialize const.

JavaScript

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

Correct.

Java

let list=vec![24,77,87]; let head=&list[0]; list.push(92);

let mut list=vec![24,77,87]; let head=list[0]; list.push(92);

Copy instead of reference.

Rust

var x = 33;

Correct.

Dart

UPDATE users SET age='test' WHERE role=16

UPDATE users SET age='test' WHERE role=16;

Add semicolon.

SQL

.User {{ color: red; }}

Correct.

CSS

def baz puts 'message' end

Correct.

Ruby

echo output data

echo 'output data'

Quote to prevent splitting.

Shell

DELETE FROM products WHERE email=8

DELETE FROM products WHERE email=8;

Add semicolon.

SQL

'value' + 25

'value' + 25.to_s

Convert int.

Ruby

console.log('test'

console.log('test')

Close parenthesis.

JavaScript

name: info age: 31

Correct.

YAML

while result > 98 result -= 1

while result > 98: result -= 1

Colon missing after while.

Python

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

if (foo = 100) {{}}

if (foo === 100) {{}}

Use === for equality.

JavaScript

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

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

Arrow functions are cleaner.

JavaScript

SELECT COUNT(*) FROM items

SELECT COUNT(*) FROM items;

Missing semicolon.

SQL

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

Correct.

Python

Add alt text.

HTML

["output", 16]

Correct.

JSON

<center>output</center>

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

Use CSS.

HTML

if foo = 99:

if foo == 99:

Use == for comparison.

Python

let val = 25; let val = 62;

let val = 25; val = 62;

Duplicate declaration.

JavaScript

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

const obj:Person = {{name:'result', age:34}};

Add missing property.

TypeScript

if (z = 41)

if (z == 41)

Use ==.

R

value: hello value: world,

value: hello value: world

Remove comma.

YAML

result = 56

result=56

No spaces.

Shell

function foo() {{ echo 'output'; }}

Correct.

PHP

items[84]

if (items.indices.contains(84)) items[84]

Check index.

Kotlin

print 'result'

print('result')

print needs parentheses.

Python

div {{ color=blue; }}

div {{ color: blue; }}

Use colon.

CSS

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

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

Make field public.

Java

while read line; do echo $line; done < input.csv

Correct.

Shell

result == '42'

result === 42

Use strict equality.

JavaScript

my @arr = (25,92,60);

Correct.

Perl

let index: number | null = null; index.toFixed(75);

let index: number | null = null; if(index!==null) index.toFixed(75);

Null check.

TypeScript

foo

foo()

Add parentheses.

Swift

if ($foo = 56) {{}}

if ($foo -eq 56) {{}}

Use -eq.

PowerShell

Colon missing.

Python

for (int i=0; i<3; i++) {{}}

Correct.

Java

$items[22] = 5;

if (isset($items[22])) $items[22] = 5;

Check existence.

PHP

$values[86]

if ($values.Count -gt 86) {{ $values[86] }}

Check bounds.

PowerShell

Post.save();

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

Handle promise.

Node.js

val a = 36; a = 41

var a = 36; a = 41

Use var for reassignment.

Scala

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

val x = 'data'

val x = "data"

Double quotes.

Kotlin

[x*x for x in list if x > 74]

Correct list comprehension.

Python

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

function handle(val) print(val) end

Correct.

Lua

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

Correct.

Shell

print 'hello'

print('hello')

Parentheses for function call.

Lua

$x = 76; if ($x = 76) {{}}

$x = 76; if ($x == 76) {{}}

Use ==.

PHP

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

def test(): print('hello')

Indent function body.

Python

h1 {{ font-size:17px color:red; }}

h1 {{ font-size:17px; color:red; }}

Add semicolon.

CSS

var x int

Correct.

Go

int bar = 'output';

String bar = 'output';

Type mismatch.

Dart

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

Correct.

R

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

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

Declare before use.

C++

package main func main() {{}}

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

Import needed.

Go

raise 'result'

raise Exception('result')

Raise needs an exception class.

Python

int main() {{ return 0; }}

Correct.

C++

Add name attribute.

HTML

arr[31]

if arr.indices.contains(31) {{ arr[31] }}

Check index.

Swift

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

Add rel for security.

HTML

// comment

/* comment */

Use /* */.

CSS

if x = 75 {{}}

if x == 75 {{}}

Use ==.

Swift

Use double quotes.

JSON

{ "name": "test" }

Correct.

JSON

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

Add comma.

JSON

echo 'output'

echo 'output';

Add semicolon.

PHP

SELECT id status FROM items;

SELECT id, status FROM items;

Add comma.

SQL

def foo(y): return y + 1

Correct.

Python

System.out.println('info')

System.out.println('info');

Add semicolon.

Java

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

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

Add return type Unit.

Scala

values[90]

if (length(values) >= 90) values[90]

Check length.

R

function render(temp:string){{return temp;}} render(59);

function render(temp:string){{return temp;}} render('data');

Pass correct type.

TypeScript

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

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

Type not in union.

TypeScript