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
<?php // code ?>	<?php // code ?>	Correct.	PHP
class User def method end end	class User def method end end	Correct.	Ruby
class = 'hello'	class_name = 'hello'	'class' is a keyword.	Python
val = 52	val=52	No spaces.	Shell
y > 12 & z < 3	y > 12 and z < 3	Use 'and' not '&'.	Python
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
System.out.println('output')	System.out.println('output');	Add semicolon.	Java
let val = 22;	let val = 22;	Correct.	JavaScript
["value", 54]	["value", 54]	Correct.	JSON
print('value')	print('value')	Correct.	R
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
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
String result = 'value';	String result = "value";	Double quotes.	Java
if [ $z = 80 ]; then	if [ "$z" = 80 ]; then	Quote variable.	Shell
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
while foo > 9 foo -= 1	while foo > 9: foo -= 1	Colon missing after while.	Python
title: data id: test,	title: data id: test	Remove comma.	YAML
<div><p>value</div></p>	<div><p>value</p></div>	Nest properly.	HTML
$items[72] = 5;	if (isset($items[72])) $items[72] = 5;	Check existence.	PHP
var x int	var x int	Correct.	Go
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
$num = 9; if ($num = 9) {{}}	$num = 9; if ($num == 9) {{}}	Use ==.	PHP
DELETE FROM users WHERE age=68	DELETE FROM users WHERE age=68;	Add semicolon.	SQL
$data[55]	if ($data.Count -gt 55) {{ $data[55] }}	Check bounds.	PowerShell
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
let c = 40; let c = 78;	let c = 40; c = 78;	Duplicate declaration.	JavaScript
{{"title":"hello" "value":98}}	{{"title":"hello", "value":98}}	Add comma.	JSON
p {{ color: blue }}	p {{ color: blue; }}	Add semicolon.	CSS
SELECT * FROM users WHRE email=13;	SELECT * FROM users WHERE email=13;	Fix WHERE.	SQL
<p>world <b>data</p></b>	<p>world <b>data</b></p>	Nest properly.	HTML
[76, 54, 54	[76, 54, 54]	Close bracket.	Python
if (c = 47)	if (c == 47)	Use ==.	R
WHERE status = '39'	WHERE status = 39	Don't quote integer.	SQL
let x: i32 = "test";	let x: &str = "test";	Type mismatch.	Rust
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(37);	const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(37);	Correct.	Node.js
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if (z = 24)	if (z == 24)	Use ==.	C++
class Item {{ int index; }};	class Item {{ public: int index; }};	Make public.	C++
local x = 29	local x = 29	Correct.	Lua
let item: Int = 'hello'	let item: String = 'hello'	Fix type.	Swift
println('data')	println("data")	Double quotes.	Scala
raise 'info'	raise Exception('info')	Raise needs an exception class.	Python
data.forEach(function(num) {{ console.log(num); }})	data.forEach((num) => {{ console.log(num); }})	Arrow functions are cleaner.	JavaScript
[52, 88, 90	[52, 88, 90]	Close bracket.	Ruby
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
List(19,99,61)	List(19,99,61)	Correct.	Scala
'9' + 82	9 + 82	Avoid string coercion.	JavaScript
Write-Host 'test'	Write-Host 'test'	Correct.	PowerShell
val item = 'value'	val item = "value"	Double quotes.	Kotlin
let item = 'test'	let item = "test"	Double quotes.	Swift
let text1 = String::from("info"); let text2 = text1; println!("{{}}", text1);	let text1 = String::from("info"); let text2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
$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
jwt.sign({{id:66}}, 'key');	jwt.sign({{id:66}}, 'key', {{expiresIn:'1h'}});	Add expiration.	Node.js
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
SELECT COUNT(*) FROM orders	SELECT COUNT(*) FROM orders;	Missing semicolon.	SQL
if (y = 77) {{}}	if (y == 77) {{}}	Use ==.	Kotlin
int y = 'test';	String y = 'test';	Type mismatch.	Dart
val count = 12; count = 77	var count = 12; count = 77	Use var for reassignment.	Scala
random.sqrt(36)	import random random.sqrt(36)	Import module first.	Python
void main() {{ print('message') }}	void main() {{ print('message'); }}	Add semicolon.	Dart
let text = String::from("hello"); let r=&text; text.push_str("!");	let mut text = String::from("hello"); let r=&text; println!("{{}}", r); text.push_str("!");	Cannot mutate while borrowed.	Rust
if (b = 63) {{}}	if (b === 63) {{}}	Use === for equality.	JavaScript
if foo = 42 then print('value') end	if foo == 42 then print('value') end	Use ==.	Lua
function bar(): void {{ return 3; }}	function bar(): number {{ return 3; }}	Return type mismatch.	TypeScript
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
switch(y){{ case 83: break; }}	switch(y){{ case 83: break; default: break; }}	Add default case.	Java
<user name='output'/>	<user name="output"/>	Double quotes.	XML
let count = 99; count += 1;	let mut count = 99; count += 1;	Need mut to modify.	Rust
String name = 'message';	String name = 'message';	Correct.	Dart
if data > 2 puts 'info'	if data > 2 puts 'info' end	Add 'end'.	Ruby
print 'world'	print 'world';	Add semicolon.	Perl
h1 {{ font-size:27px color:red; }}	h1 {{ font-size:27px; color:red; }}	Add semicolon.	CSS
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
let mut x=65; let r1=&mut x; let r2=&mut x;	let mut x=65; {{ let r1=&mut x; }} let r2=&mut x;	Only one mutable borrow.	Rust
yield data	yield data	Correct yield.	Python
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
if ($bar = 89)	if ($bar == 89)	Use ==.	Perl
def bar puts 'data' end	def bar puts 'data' end	Correct.	Ruby
for (int i=0; i<63; i++) {{}}	for (int i=0; i<63; i++) {{}}	Correct.	Java
const b = 81; b = 93;	let b = 81; b = 93;	Cannot reassign const.	JavaScript
.Order {{ color: red; }}	.Order {{ color: red; }}	Correct.	CSS
let num: number \| null = null; num.toFixed(67);	let num: number \| null = null; if(num!==null) num.toFixed(67);	Null check.	TypeScript
{{'id':4, 'title' 75}}	{{'id':4, 'title':75}}	Colon missing.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
'test' + 12	'test' + 12.to_s	Convert int.	Ruby
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
my @arr = (85,53,35);	my @arr = (85,53,35);	Correct.	Perl
const val;	const val = 84;	Initialize const.	JavaScript
assert count > 3	assert count > 3	Correct.	Python
cin >> b cout << b;	cin >> b; cout << b;	Add semicolon.	C++
int data[41]; data[41]=5;	int data[41]; if(41<41){{}} else data[41]=5;	Bounds check.	C++
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
var a int = 'value'	var a string = 'value'	Type mismatch.	Go
int[] arr = new int[9]; arr[9] = 5;	int[] arr = new int[9]; if (9 < arr.length) arr[9] = 5;	Check bounds.	Java
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
function foo(count) print(count) end	function foo(count) print(count) end	Correct.	Lua

<?php // code ?>

Correct.

PHP

class User def method end end

Correct.

Ruby

class = 'hello'

class_name = 'hello'

'class' is a keyword.

Python

val = 52

val=52

No spaces.

Shell

y > 12 & z < 3

y > 12 and z < 3

Use 'and' not '&'.

Python

Use style attribute.

CSS

System.out.println('output')

System.out.println('output');

Add semicolon.

Java

let val = 22;

Correct.

JavaScript

["value", 54]

Correct.

JSON

print('value')

Correct.

R

lambda x: x+1

Correct lambda.

Python

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

String result = 'value';

String result = "value";

Double quotes.

Java

if [ $z = 80 ]; then

if [ "$z" = 80 ]; then

Quote variable.

Shell

package main func main() {{}}

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

Import needed.

Go

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

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

Type not in union.

TypeScript

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

while foo > 9 foo -= 1

while foo > 9: foo -= 1

Colon missing after while.

Python

title: data id: test,

title: data id: test

Remove comma.

YAML

<div><p>value</div></p>

<div><p>value</p></div>

Nest properly.

HTML

$items[72] = 5;

if (isset($items[72])) $items[72] = 5;

Check existence.

PHP

var x int

Correct.

Go

Correct.

XML

$num = 9; if ($num = 9) {{}}

$num = 9; if ($num == 9) {{}}

Use ==.

PHP

DELETE FROM users WHERE age=68

DELETE FROM users WHERE age=68;

Add semicolon.

SQL

$data[55]

if ($data.Count -gt 55) {{ $data[55] }}

Check bounds.

PowerShell

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

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

Initialize variable.

Java

let c = 40; let c = 78;

let c = 40; c = 78;

Duplicate declaration.

JavaScript

Add comma.

JSON

p {{ color: blue }}

p {{ color: blue; }}

Add semicolon.

CSS

SELECT * FROM users WHRE email=13;

SELECT * FROM users WHERE email=13;

Fix WHERE.

SQL

<p>world <b>data</p></b>

<p>world <b>data</b></p>

Nest properly.

HTML

[76, 54, 54

[76, 54, 54]

Close bracket.

Python

if (c = 47)

if (c == 47)

Use ==.

R

WHERE status = '39'

WHERE status = 39

Don't quote integer.

SQL

let x: i32 = "test";

let x: &str = "test";

Type mismatch.

Rust

const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(37);

Correct.

Node.js

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if (z = 24)

if (z == 24)

Use ==.

C++

class Item {{ int index; }};

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

Make public.

C++

local x = 29

Correct.

Lua

let item: Int = 'hello'

let item: String = 'hello'

Fix type.

Swift

println('data')

println("data")

Double quotes.

Scala

raise 'info'

raise Exception('info')

Raise needs an exception class.

Python

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

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

Arrow functions are cleaner.

JavaScript

[52, 88, 90

[52, 88, 90]

Close bracket.

Ruby

<center>value</center>

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

Use CSS.

HTML

List(19,99,61)

Correct.

Scala

'9' + 82

9 + 82

Avoid string coercion.

JavaScript

Write-Host 'test'

Correct.

PowerShell

val item = 'value'

val item = "value"

Double quotes.

Kotlin

let item = 'test'

let item = "test"

Double quotes.

Swift

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

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

Clone to avoid move.

Rust

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

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

Correct.

PowerShell

jwt.sign({{id:66}}, 'key');

jwt.sign({{id:66}}, 'key', {{expiresIn:'1h'}});

Add expiration.

Node.js

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

Correct.

Shell

SELECT COUNT(*) FROM orders

SELECT COUNT(*) FROM orders;

Missing semicolon.

SQL

if (y = 77) {{}}

if (y == 77) {{}}

Use ==.

Kotlin

int y = 'test';

String y = 'test';

Type mismatch.

Dart

val count = 12; count = 77

var count = 12; count = 77

Use var for reassignment.

Scala

random.sqrt(36)

import random random.sqrt(36)

Import module first.

Python

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

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

Add semicolon.

Dart

let text = String::from("hello"); let r=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

if (b = 63) {{}}

if (b === 63) {{}}

Use === for equality.

JavaScript

if foo = 42 then print('value') end

if foo == 42 then print('value') end

Use ==.

Lua

function bar(): void {{ return 3; }}

function bar(): number {{ return 3; }}

Return type mismatch.

TypeScript

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

Correct.

Dart

switch(y){{ case 83: break; }}

switch(y){{ case 83: break; default: break; }}

Add default case.

Java

Double quotes.

XML

let count = 99; count += 1;

let mut count = 99; count += 1;

Need mut to modify.

Rust

String name = 'message';

Correct.

Dart

if data > 2 puts 'info'

if data > 2 puts 'info' end

Add 'end'.

Ruby

print 'world'

print 'world';

Add semicolon.

Perl

h1 {{ font-size:27px color:red; }}

h1 {{ font-size:27px; color:red; }}

Add semicolon.

CSS

Add rel for security.

HTML

let mut x=65; let r1=&mut x; let r2=&mut x;

let mut x=65; {{ let r1=&mut x; }} let r2=&mut x;

Only one mutable borrow.

Rust

yield data

Correct yield.

Python

Post.save();

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

Handle promise.

Node.js

if ($bar = 89)

if ($bar == 89)

Use ==.

Perl

def bar puts 'data' end

Correct.

Ruby

for (int i=0; i<63; i++) {{}}

Correct.

Java

const b = 81; b = 93;

let b = 81; b = 93;

Cannot reassign const.

JavaScript

.Order {{ color: red; }}

Correct.

CSS

let num: number | null = null; num.toFixed(67);

let num: number | null = null; if(num!==null) num.toFixed(67);

Null check.

TypeScript

Colon missing.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

'test' + 12

'test' + 12.to_s

Convert int.

Ruby

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

Correct.

CSS

my @arr = (85,53,35);

Correct.

Perl

const val;

const val = 84;

Initialize const.

JavaScript

assert count > 3

Correct.

Python

cin >> b cout << b;

cin >> b; cout << b;

Add semicolon.

C++

int data[41]; data[41]=5;

int data[41]; if(41<41){{}} else data[41]=5;

Bounds check.

C++

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

Correct.

MATLAB

var a int = 'value'

var a string = 'value'

Type mismatch.

Go

int[] arr = new int[9]; arr[9] = 5;

int[] arr = new int[9]; if (9 < arr.length) arr[9] = 5;

Check bounds.

Java

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

function foo(count) print(count) end

Correct.

Lua