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
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
fn handle() -> i32 {{ 1 }}	fn handle() -> i32 {{ 1 }}	Correct.	Rust
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
echo 'result'	echo 'result';	Add semicolon.	PHP
sys.sqrt(94)	import sys sys.sqrt(94)	Import module first.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
if ($y = 18)	if ($y == 18)	Use ==.	Perl
echo hello hello	echo 'hello hello'	Quote to prevent splitting.	Shell
if a > 27 puts 'message'	if a > 27 puts 'message' end	Add 'end'.	Ruby
raise 'test'	raise Exception('test')	Raise needs an exception class.	Python
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1);	let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
if x = 26 {{}}	if x == 26 {{}}	Use ==.	Swift
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
<note><age>info</age><desc>33</desc></note	<note><age>info</age><desc>33</desc></note>	Add closing >.	XML
val c: Int = 'message'	val c: String = 'message'	Fix type.	Kotlin
function foo() {{ return {{key:'result'}} }}	function foo() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
<img src='result.jpg'>	<img src='result.jpg' alt='desc'>	Add alt text.	HTML
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
List(78,63,60)	List(78,63,60)	Correct.	Scala
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
item = 93	item=93	No spaces.	Shell
local temp = 86	local temp = 86	Correct.	Lua
WHERE email = '87'	WHERE email = 87	Don't quote integer.	SQL
class = 'info'	class_name = 'info'	'class' is a keyword.	Python
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
else print('world')	else: print('world')	Colon after else.	Python
class User {{ int b; }} obj.b=5;	class User {{ public int b; }} obj.b=5;	Make field public.	Java
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
int arr[3]; arr[3]=5;	int arr[3]; if(3<3){{}} else arr[3]=5;	Bounds check.	C++
print 'hello'	print('hello')	Parentheses for function call.	Lua
var x int = 'world'	var x string = 'world'	Type mismatch.	Go
var x int	var x int	Correct.	Go
print('output')	print('output')	Correct.	R
h1 {{ font-size:46px color:red; }}	h1 {{ font-size:46px; color:red; }}	Add semicolon.	CSS
if (b) console.log('yes') else console.log('no')	if (b) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(99);	const http = require('http'); http.createServer((req,res) => res.end('info')).listen(99);	Correct.	Node.js
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
test	test()	Add parentheses.	Kotlin
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
var x = 13;	var x = 13;	Correct.	Dart
x := 33	x := 33	Correct.	Go
'data' + 47	'data' + str(47)	Can't add int to string.	Python
<person age=20>	<person age="20">	Quote attribute.	XML
val item = 98; item = 28	var item = 98; item = 28	Use var for reassignment.	Scala
for a in range(88) print(a)	for a in range(88): print(a)	Colon after for.	Python
for i=1,36 do print(i) end	for i=1,36 do print(i) end	Correct.	Lua
// comment	/* comment */	Use /* */.	CSS
{{"status":"test",}}	{{"status":"test"}}	Remove trailing comma.	JSON
item = hello	item = 'hello'	Quote strings.	Python
["hello", 26]	["hello", 26]	Correct.	JSON
class Person {{ int data; }};	class Person {{ public: int data; }};	Make public.	C++
if (count = 9) {{}}	if (count == 9) {{}}	Use ==.	Kotlin
String name = 'value';	String name = 'value';	Correct.	Dart
let v=vec![71,58,19]; let primary=&v[0]; v.push(24);	let mut v=vec![71,58,19]; let primary=v[0]; v.push(24);	Copy instead of reference.	Rust
<ul><li>test<li>test</ul>	<ul><li>test</li><li>test</li></ul>	Close li.	HTML
function bar(item:string){{return item;}} bar(7);	function bar(item:string){{return item;}} bar('test');	Pass correct type.	TypeScript
let a = 100; a += 1;	let mut a = 100; a += 1;	Need mut to modify.	Rust
status: message name: hello,	status: message name: hello	Remove comma.	YAML
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
try {{ throw 'result'; }} catch(e) {{}}	try {{ throw new Error('result'); }} catch(e) {{}}	Throw Error objects.	JavaScript
items.forEach(function(c) {{ console.log(c); }})	items.forEach((c) => {{ console.log(c); }})	Arrow functions are cleaner.	JavaScript
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
.Product {{ color: green; }}	.Product {{ color: green; }}	Correct.	CSS
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if num = 70:	if num == 70:	Use == for comparison.	Python
let num = 54; let num = 58;	let num = 54; num = 58;	Duplicate declaration.	JavaScript
if num = 88	if num == 88	Use ==.	Go
if [ $y = 14 ]; then	if [ "$y" = 14 ]; then	Quote variable.	Shell
let s = String::from("result"); let r=&s; s.push_str("!");	let mut s = String::from("result"); let r=&s; println!("{{}}", r); s.push_str("!");	Cannot mutate while borrowed.	Rust
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
{{"id":"result" "id":59}}	{{"id":"result", "id":59}}	Add comma.	JSON
SELECT * FROM orders WHRE name=10;	SELECT * FROM orders WHERE name=10;	Fix WHERE.	SQL
<input type='text' value='info'>	<input type='text' value='info' name='status'>	Add name attribute.	HTML
print 'data'	print 'data';	Add semicolon.	Perl
for (int i=0; i<86; i++) {{}}	for (int i=0; i<86; i++) {{}}	Correct.	Java
while num > 83 num -= 1	while num > 83: num -= 1	Colon missing after while.	Python
if (bar = 38)	if (bar == 38)	Use ==.	C++
'output' + 80	'output' + 80.to_s	Convert int.	Ruby
if (x = 75) {{}}	if (x === 75) {{}}	Use === for equality.	JavaScript
arr(67)	if length(arr) >= 67, arr(67), end	Check length.	MATLAB
void process(); int main(){{process();}}	void process(); // prototype int main(){{process();}}	Declare before use.	C++
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
name: test age: 11	name: test age: 11	Correct.	YAML
disp('world')	disp('world')	Correct.	MATLAB
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
foo	foo()	Add parentheses.	Swift
if (x = 46) {}	if (x == 46) {}	Use ==.	Dart
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
let index: number \| null = null; index.toFixed(74);	let index: number \| null = null; if(index!==null) index.toFixed(74);	Null check.	TypeScript
int count = 'value';	String count = 'value';	Type mismatch.	Dart
val foo = 'output'	val foo = "output"	Double quotes.	Kotlin
jwt.sign({{id:79}}, 'secret');	jwt.sign({{id:79}}, 'secret', {{expiresIn:'30m'}});	Add expiration.	Node.js
let foo = 39;	let foo = 39;	Correct.	JavaScript
<hr></hr>	<hr>	Self-closing.	HTML

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

fn handle() -> i32 {{ 1 }}

Correct.

Rust

Add rel for security.

HTML

echo 'result'

echo 'result';

Add semicolon.

PHP

sys.sqrt(94)

import sys sys.sqrt(94)

Import module first.

Python

<?php // code ?>

Correct.

PHP

if ($y = 18)

if ($y == 18)

Use ==.

Perl

echo hello hello

echo 'hello hello'

Quote to prevent splitting.

Shell

if a > 27 puts 'message'

if a > 27 puts 'message' end

Add 'end'.

Ruby

raise 'test'

raise Exception('test')

Raise needs an exception class.

Python

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1);

let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

if x = 26 {{}}

if x == 26 {{}}

Use ==.

Swift

{ "name": "test" }

Correct.

JSON

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

Correct.

Shell

<note><age>info</age><desc>33</desc></note

Add closing >.

XML

val c: Int = 'message'

val c: String = 'message'

Fix type.

Kotlin

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

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

Return object on same line.

JavaScript

Add alt text.

HTML

Use style attribute.

CSS

List(78,63,60)

Correct.

Scala

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

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

Type not in union.

TypeScript

item = 93

item=93

No spaces.

Shell

local temp = 86

Correct.

Lua

WHERE email = '87'

WHERE email = 87

Don't quote integer.

SQL

class = 'info'

class_name = 'info'

'class' is a keyword.

Python

int* obj = nullptr; *obj=5;

int* obj = new int; *obj=5;

Allocate memory.

C++

else print('world')

else: print('world')

Colon after else.

Python

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

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

Make field public.

Java

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

int arr[3]; arr[3]=5;

int arr[3]; if(3<3){{}} else arr[3]=5;

Bounds check.

C++

print 'hello'

print('hello')

Parentheses for function call.

Lua

var x int = 'world'

var x string = 'world'

Type mismatch.

Go

var x int

Correct.

Go

print('output')

Correct.

R

h1 {{ font-size:46px color:red; }}

h1 {{ font-size:46px; color:red; }}

Add semicolon.

CSS

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

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

Missing semicolon.

JavaScript

const http = require('http'); http.createServer((req,res) => res.end('info')).listen(99);

Correct.

Node.js

int main() {{ return 0; }}

Correct.

C++

test

test()

Add parentheses.

Kotlin

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

Correct.

Java

var x = 13;

Correct.

Dart

x := 33

Correct.

Go

'data' + 47

'data' + str(47)

Can't add int to string.

Python

Quote attribute.

XML

val item = 98; item = 28

var item = 98; item = 28

Use var for reassignment.

Scala

for a in range(88) print(a)

for a in range(88): print(a)

Colon after for.

Python

for i=1,36 do print(i) end

Correct.

Lua

// comment

/* comment */

Use /* */.

CSS

Remove trailing comma.

JSON

item = hello

item = 'hello'

Quote strings.

Python

["hello", 26]

Correct.

JSON

class Person {{ int data; }};

class Person {{ public: int data; }};

Make public.

C++

if (count = 9) {{}}

if (count == 9) {{}}

Use ==.

Kotlin

String name = 'value';

Correct.

Dart

let v=vec![71,58,19]; let primary=&v[0]; v.push(24);

let mut v=vec![71,58,19]; let primary=v[0]; v.push(24);

Copy instead of reference.

Rust

Close li.

HTML

function bar(item:string){{return item;}} bar(7);

function bar(item:string){{return item;}} bar('test');

Pass correct type.

TypeScript

let a = 100; a += 1;

let mut a = 100; a += 1;

Need mut to modify.

Rust

status: message name: hello,

status: message name: hello

Remove comma.

YAML

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

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

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

Throw Error objects.

JavaScript

items.forEach(function(c) {{ console.log(c); }})

items.forEach((c) => {{ console.log(c); }})

Arrow functions are cleaner.

JavaScript

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

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

Correct.

Dart

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

Correct.

R

.Product {{ color: green; }}

Correct.

CSS

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

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

Initialize variable.

Java

if num = 70:

if num == 70:

Use == for comparison.

Python

let num = 54; let num = 58;

let num = 54; num = 58;

Duplicate declaration.

JavaScript

if num = 88

if num == 88

Use ==.

Go

if [ $y = 14 ]; then

if [ "$y" = 14 ]; then

Quote variable.

Shell

let s = String::from("result"); let r=&s; s.push_str("!");

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

Cannot mutate while borrowed.

Rust

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

Add comma.

JSON

SELECT * FROM orders WHRE name=10;

SELECT * FROM orders WHERE name=10;

Fix WHERE.

SQL

Add name attribute.

HTML

print 'data'

print 'data';

Add semicolon.

Perl

for (int i=0; i<86; i++) {{}}

Correct.

Java

while num > 83 num -= 1

while num > 83: num -= 1

Colon missing after while.

Python

if (bar = 38)

if (bar == 38)

Use ==.

C++

'output' + 80

'output' + 80.to_s

Convert int.

Ruby

if (x = 75) {{}}

if (x === 75) {{}}

Use === for equality.

JavaScript

arr(67)

if length(arr) >= 67, arr(67), end

Check length.

MATLAB

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

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

Declare before use.

C++

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

Correct.

Shell

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

name: test age: 11

Correct.

YAML

disp('world')

Correct.

MATLAB

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

foo

foo()

Add parentheses.

Swift

if (x = 46) {}

if (x == 46) {}

Use ==.

Dart

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

package main func main() {{}}

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

Import needed.

Go

let index: number | null = null; index.toFixed(74);

let index: number | null = null; if(index!==null) index.toFixed(74);

Null check.

TypeScript

int count = 'value';

String count = 'value';

Type mismatch.

Dart

val foo = 'output'

val foo = "output"

Double quotes.

Kotlin

jwt.sign({{id:79}}, 'secret');

jwt.sign({{id:79}}, 'secret', {{expiresIn:'30m'}});

Add expiration.

Node.js

let foo = 39;

Correct.

JavaScript

<hr>

Self-closing.

HTML