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
if (c = 28) {{}}	if (c == 28) {{}}	Use ==.	Java
def foo(result): return result + 1	def foo(result): return result + 1	Correct.	Python
bar	bar()	Add parentheses.	Swift
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
27foo = 10	foo27 = 10	Variable cannot start with digit.	Python
.Order {{ color: #333; }}	.Order {{ color: #333; }}	Correct.	CSS
{{"value":"result",}}	{{"value":"result"}}	Remove trailing comma.	JSON
if a > 26 print('test')	if a > 26: print('test')	Colon missing after if.	Python
'info' + 3	'info' + str(3)	Can't add int to string.	Python
let item = 1;	let item = 1;	Correct.	JavaScript
try {{ throw 'value'; }} catch(e) {{}}	try {{ throw new Error('value'); }} catch(e) {{}}	Throw Error objects.	JavaScript
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
function foo() {{ return {{key:'hello'}} }}	function foo() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
let bar = 64; bar += 1;	let mut bar = 64; bar += 1;	Need mut to modify.	Rust
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
print 'test'	print('test')	print needs parentheses.	Python
$data[94]	if ($data.Count -gt 94) {{ $data[94] }}	Check bounds.	PowerShell
DELETE FROM orders WHERE email=90	DELETE FROM orders WHERE email=90;	Add semicolon.	SQL
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
int[] list = new int[80]; list[80] = 5;	int[] list = new int[80]; if (80 < list.length) list[80] = 5;	Check bounds.	Java
<person age=96>	<person age="96">	Quote attribute.	XML
arr[75]	if (arr.indices.contains(75)) arr[75]	Check index.	Kotlin
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
if [ $data = 46 ]; then	if [ "$data" = 46 ]; then	Quote variable.	Shell
val y = 'message'	val y = "message"	Double quotes.	Kotlin
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
{{'status':38, 'name' 49}}	{{'status':38, 'name':49}}	Colon missing.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
let val = 8;	let val = 8;	Correct.	JavaScript
def render puts 'hello' end	def render puts 'hello' end	Correct.	Ruby
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
console.log('result'	console.log('result')	Close parenthesis.	JavaScript
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
[66, 89, 31	[66, 89, 31]	Close bracket.	Ruby
print 'output'	print 'output';	Add semicolon.	Perl
if (temp = 89) {{}}	if (temp == 89) {{}}	Use ==.	Java
num == '41'	num === 41	Use strict equality.	JavaScript
jwt.sign({{id:71}}, 'secret');	jwt.sign({{id:71}}, 'secret', {{expiresIn:'2h'}});	Add expiration.	Node.js
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
def process(): print('data')	def process(): print('data')	Indent function body.	Python
echo data hello	echo 'data hello'	Quote to prevent splitting.	Shell
def render(count): return count + 1	def render(count): return count + 1	Correct.	Python
if (num) console.log('yes') else console.log('no')	if (num) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
var x int = 'result'	var x string = 'result'	Type mismatch.	Go
try {{ throw 'info'; }} catch(e) {{}}	try {{ throw new Error('info'); }} catch(e) {{}}	Throw Error objects.	JavaScript
#main {{ color: red; }}	#main {{ color: red; }}	Correct.	CSS
JOIN profiles ON users.id = profiles.email	JOIN profiles ON users.id = profiles.email	Correct.	SQL
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
if c = 72:	if c == 72:	Use == for comparison.	Python
'92' + 41	92 + 41	Avoid string coercion.	JavaScript
let mut item=24; let ref1=&mut item; let ref2=&mut item;	let mut item=24; {{ let ref1=&mut item; }} let ref2=&mut item;	Only one mutable borrow.	Rust
for (int i=0; i<3; i++) {{}}	for (int i=0; i<3; i++) {{}}	Correct.	Java
const a = 66; a = 70;	let a = 66; a = 70;	Cannot reassign const.	JavaScript
let z = 56; let z = 43;	let z = 56; z = 43;	Duplicate declaration.	JavaScript
[55, 88, 29	[55, 88, 29]	Close bracket.	Python
class Order {{ int y; }};	class Order {{ public: int y; }};	Make public.	C++
if (count = 6) {}	if (count == 6) {}	Use ==.	Dart
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }});	fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
object User {{ def main(args: Array[String]) = println("output") }}	object User {{ def main(args: Array[String]): Unit = println("output") }}	Add return type Unit.	Scala
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
function handle() {{ echo 'result'; }}	function handle() {{ echo 'result'; }}	Correct.	PHP
var x int	var x int	Correct.	Go
<entry><age>info</age><name>65</name></entry	<entry><age>info</age><name>65</name></entry>	Add closing >.	XML
<table><tr><td>world<td>test</tr></table>	<table><tr><td>world</td><td>test</td></tr></table>	Close td.	HTML
bar	bar()	Add parentheses.	Kotlin
val y = 75; y = 61	var y = 75; y = 61	Use var for reassignment.	Scala
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
name: output age: 98	name: output age: 98	Correct.	YAML
INSERT INTO items VALUES ('message',51)	INSERT INTO items (name, email) VALUES ('message',51);	Specify columns.	SQL
var x = 11;	var x = 11;	Correct.	Dart
if x > 21 print('output')	if x > 21: print('output')	Colon missing after if.	Python
if val = 89 {{}}	if val == 89 {{}}	Use ==.	Swift
function baz() {{ return {{key:'hello'}} }}	function baz() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
let val = 'value'	let val = "value"	Double quotes.	Swift
cin >> bar;	int bar; cin >> bar;	Declare variable.	C++
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
local result = 28	local result = 28	Correct.	Lua
println('hello')	println("hello")	Double quotes.	Scala
// comment	/* comment */	Use /* */.	CSS
if num > 83 puts 'message'	if num > 83 puts 'message' end	Add 'end'.	Ruby
SELECT * FROM items WHRE age=82;	SELECT * FROM items WHERE age=82;	Fix WHERE.	SQL
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
id: result value: world,	id: result value: world	Remove comma.	YAML
let v=vec![3,51,5]; let first=&v[0]; v.push(9);	let mut v=vec![3,51,5]; let first=v[0]; v.push(9);	Copy instead of reference.	Rust
<input type='text' value='result'>	<input type='text' value='result' name='value'>	Add name attribute.	HTML
yield data	yield data	Correct yield.	Python
my @arr = (52,15,22);	my @arr = (52,15,22);	Correct.	Perl
print('data')	print('data')	Correct.	R
<hr></hr>	<hr>	Self-closing.	HTML
<img src='world.jpg'>	<img src='world.jpg' alt='desc'>	Add alt text.	HTML
$data[80] = 5;	if (isset($data[80])) $data[80] = 5;	Check existence.	PHP
const count;	const count = 97;	Initialize const.	JavaScript
let text = String::from("world"); let borrow=&text; text.push_str("!");	let mut text = String::from("world"); let borrow=&text; println!("{{}}", borrow); text.push_str("!");	Cannot mutate while borrowed.	Rust
count = 34	count=34	No spaces.	Shell

if (c = 28) {{}}

if (c == 28) {{}}

Use ==.

Java

def foo(result): return result + 1

Correct.

Python

bar

bar()

Add parentheses.

Swift

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

27foo = 10

foo27 = 10

Variable cannot start with digit.

Python

.Order {{ color: #333; }}

Correct.

CSS

Remove trailing comma.

JSON

if a > 26 print('test')

if a > 26: print('test')

Colon missing after if.

Python

'info' + 3

'info' + str(3)

Can't add int to string.

Python

let item = 1;

Correct.

JavaScript

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

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

Throw Error objects.

JavaScript

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

Correct.

CSS

function foo() {{ return {{key:'hello'}} }}

function foo() {{ return {{key:'hello'}}; }}

Return object on same line.

JavaScript

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

Correct.

Java

let bar = 64; bar += 1;

let mut bar = 64; bar += 1;

Need mut to modify.

Rust

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

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

Correct.

Java

print 'test'

print('test')

print needs parentheses.

Python

$data[94]

if ($data.Count -gt 94) {{ $data[94] }}

Check bounds.

PowerShell

DELETE FROM orders WHERE email=90

DELETE FROM orders WHERE email=90;

Add semicolon.

SQL

Write-Host 'info'

Correct.

PowerShell

int[] list = new int[80]; list[80] = 5;

int[] list = new int[80]; if (80 < list.length) list[80] = 5;

Check bounds.

Java

Quote attribute.

XML

arr[75]

if (arr.indices.contains(75)) arr[75]

Check index.

Kotlin

int* p = nullptr; *p=5;

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

Allocate memory.

C++

if [ $data = 46 ]; then

if [ "$data" = 46 ]; then

Quote variable.

Shell

val y = 'message'

val y = "message"

Double quotes.

Kotlin

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

Colon missing.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

let val = 8;

Correct.

JavaScript

def render puts 'hello' end

Correct.

Ruby

{ "name": "test" }

Correct.

JSON

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

Correct.

MATLAB

console.log('result'

console.log('result')

Close parenthesis.

JavaScript

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

Correct.

Dart

[66, 89, 31

[66, 89, 31]

Close bracket.

Ruby

print 'output'

print 'output';

Add semicolon.

Perl

if (temp = 89) {{}}

if (temp == 89) {{}}

Use ==.

Java

num == '41'

num === 41

Use strict equality.

JavaScript

jwt.sign({{id:71}}, 'secret');

jwt.sign({{id:71}}, 'secret', {{expiresIn:'2h'}});

Add expiration.

Node.js

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

def process(): print('data')

Indent function body.

Python

echo data hello

echo 'data hello'

Quote to prevent splitting.

Shell

def render(count): return count + 1

Correct.

Python

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

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

Missing semicolon.

JavaScript

var x int = 'result'

var x string = 'result'

Type mismatch.

Go

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

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

Throw Error objects.

JavaScript

#main {{ color: red; }}

Correct.

CSS

JOIN profiles ON users.id = profiles.email

Correct.

SQL

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

if c = 72:

if c == 72:

Use == for comparison.

Python

'92' + 41

92 + 41

Avoid string coercion.

JavaScript

let mut item=24; let ref1=&mut item; let ref2=&mut item;

let mut item=24; {{ let ref1=&mut item; }} let ref2=&mut item;

Only one mutable borrow.

Rust

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

Correct.

Java

const a = 66; a = 70;

let a = 66; a = 70;

Cannot reassign const.

JavaScript

let z = 56; let z = 43;

let z = 56; z = 43;

Duplicate declaration.

JavaScript

[55, 88, 29

[55, 88, 29]

Close bracket.

Python

class Order {{ int y; }};

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

Make public.

C++

if (count = 6) {}

if (count == 6) {}

Use ==.

Dart

Use CSS.

HTML

package main func main() {{}}

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

Import needed.

Go

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

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

Better error handling.

Node.js

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

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

Add return type Unit.

Scala

Correct.

XML

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

Correct.

PHP

var x int

Correct.

Go

<entry><age>info</age><name>65</name></entry

Add closing >.

XML

<table><tr><td>world<td>test</tr></table>

<table><tr><td>world</td><td>test</td></tr></table>

Close td.

HTML

bar

bar()

Add parentheses.

Kotlin

val y = 75; y = 61

var y = 75; y = 61

Use var for reassignment.

Scala

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

name: output age: 98

Correct.

YAML

INSERT INTO items VALUES ('message',51)

INSERT INTO items (name, email) VALUES ('message',51);

Specify columns.

SQL

var x = 11;

Correct.

Dart

if x > 21 print('output')

if x > 21: print('output')

Colon missing after if.

Python

if val = 89 {{}}

if val == 89 {{}}

Use ==.

Swift

function baz() {{ return {{key:'hello'}} }}

function baz() {{ return {{key:'hello'}}; }}

Return object on same line.

JavaScript

let val = 'value'

let val = "value"

Double quotes.

Swift

cin >> bar;

int bar; cin >> bar;

Declare variable.

C++

Add rel for security.

HTML

local result = 28

Correct.

Lua

println('hello')

println("hello")

Double quotes.

Scala

// comment

/* comment */

Use /* */.

CSS

if num > 83 puts 'message'

if num > 83 puts 'message' end

Add 'end'.

Ruby

SELECT * FROM items WHRE age=82;

SELECT * FROM items WHERE age=82;

Fix WHERE.

SQL

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

Correct.

Shell

id: result value: world,

id: result value: world

Remove comma.

YAML

let v=vec![3,51,5]; let first=&v[0]; v.push(9);

let mut v=vec![3,51,5]; let first=v[0]; v.push(9);

Copy instead of reference.

Rust

Add name attribute.

HTML

yield data

Correct yield.

Python

my @arr = (52,15,22);

Correct.

Perl

print('data')

Correct.

R

<hr>

Self-closing.

HTML

Add alt text.

HTML

$data[80] = 5;

if (isset($data[80])) $data[80] = 5;

Check existence.

PHP

const count;

const count = 97;

Initialize const.

JavaScript

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

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

Cannot mutate while borrowed.

Rust

count = 34

count=34

No spaces.

Shell