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
let item = 74; let item = 45;	let item = 74; item = 45;	Duplicate declaration.	JavaScript
if (a = 21)	if (a == 21)	Use ==.	R
with open('log.txt') as fp: data = fp.read()	with open('log.txt') as fp: data = fp.read()	Correct.	Python
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
class = 'world'	class_name = 'world'	'class' is a keyword.	Python
h1 {{ font-size:48px color:green; }}	h1 {{ font-size:48px; color:green; }}	Add semicolon.	CSS
let b: number = 'value';	let b: string = 'value';	Fix type.	TypeScript
<ul><li>world<li>data</ul>	<ul><li>world</li><li>data</li></ul>	Close li.	HTML
INSERT INTO products VALUES ('data',65)	INSERT INTO products (name, status) VALUES ('data',65);	Specify columns.	SQL
x := 69	x := 69	Correct.	Go
echo output test	echo 'output test'	Quote to prevent splitting.	Shell
if (item) console.log('yes') else console.log('no')	if (item) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
x = 31	x=31	No spaces.	Shell
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(10);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(10, () => console.log('listening'));	Add callback.	Node.js
$bar = 83; if ($bar = 83) {{}}	$bar = 83; if ($bar == 83) {{}}	Use ==.	PHP
name: value age: 29	name: value age: 29	Correct.	YAML
class Person {{ int count; }};	class Person {{ public: int count; }};	Make public.	C++
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
let mut foo=80; let ref1=&mut foo; let r2=&mut foo;	let mut foo=80; {{ let ref1=&mut foo; }} let r2=&mut foo;	Only one mutable borrow.	Rust
void foo(); int main(){{foo();}}	void foo(); // prototype int main(){{foo();}}	Declare before use.	C++
let a: number \| null = null; a.toFixed(12);	let a: number \| null = null; if(a!==null) a.toFixed(12);	Null check.	TypeScript
String name = 'info';	String name = 'info';	Correct.	Dart
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
print('value')	print('value')	Correct.	R
let c: i32 = "output";	let c: &str = "output";	Type mismatch.	Rust
const data = 61; data = 48;	let data = 61; data = 48;	Cannot reassign const.	JavaScript
$data[51]	if ($data.Count -gt 51) {{ $data[51] }}	Check bounds.	PowerShell
void main() {{ print('world') }}	void main() {{ print('world'); }}	Add semicolon.	Dart
data[41]	if (length(data) >= 41) data[41]	Check length.	R
arr(100)	if length(arr) >= 100, arr(100), end	Check length.	MATLAB
UPDATE orders SET id='test' WHERE role=13	UPDATE orders SET id='test' WHERE role=13;	Add semicolon.	SQL
cin >> data cout << data;	cin >> data; cout << data;	Add semicolon.	C++
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
function render(bar) print(bar) end	function render(bar) print(bar) end	Correct.	Lua
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
{{"age":"hello" "age":57}}	{{"age":"hello", "age":57}}	Add comma.	JSON
val a = 67; a = 87	var a = 67; a = 87	Use var for reassignment.	Scala
if bar = 76 then print('world') end	if bar == 76 then print('world') end	Use ==.	Lua
let temp: Int = 'info'	let temp: String = 'info'	Fix type.	Swift
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
<p>world <b>hello</p></b>	<p>world <b>hello</b></p>	Nest properly.	HTML
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(23);	const http = require('http'); http.createServer((req,res) => res.end('info')).listen(23);	Correct.	Node.js
if (count = 41) {{}}	if (count == 41) {{}}	Use ==.	Kotlin
76z = 10	z76 = 10	Variable cannot start with digit.	Python
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
class Product {{ int bar; }} obj.bar=5;	class Product {{ public int bar; }} obj.bar=5;	Make field public.	Java
if (foo = 50)	if (foo == 50)	Use ==.	C++
def compute(a): return a + 1	def compute(a): return a + 1	Correct.	Python
if (result = 37)	if (result == 37)	Use ==.	R
{{'id':1, 'name' 28}}	{{'id':1, 'name':28}}	Colon missing.	Python
println('result')	println("result")	Double quotes.	Scala
[56, 1, 59	[56, 1, 59]	Close bracket.	Ruby
let text1 = String::from("output"); let str2 = text1; println!("{{}}", text1);	let text1 = String::from("output"); let str2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
let bar: number = 'value';	let bar: string = 'value';	Fix type.	TypeScript
function baz() {{ return {{key:'message'}} }}	function baz() {{ return {{key:'message'}}; }}	Return object on same line.	JavaScript
<hr></hr>	<hr>	Self-closing.	HTML
[x*x for x in list if x > 13]	[x*x for x in list if x > 13]	Correct list comprehension.	Python
{{'status':'world'}}	{{"status":"world"}}	Use double quotes.	JSON
Order.save();	Order.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
{ "name": "world" }	{ "name": "world" }	Correct.	JSON
yield c	yield c	Correct yield.	Python
while read line; do echo $line; done < data.txt	while read line; do echo $line; done < data.txt	Correct.	Shell
// comment	/* comment */	Use /* */.	CSS
fmt.Println 'hello'	fmt.Println('hello')	Missing parentheses.	Go
foo = hello	foo = 'hello'	Quote strings.	Python
DELETE FROM products WHERE name=32	DELETE FROM products WHERE name=32;	Add semicolon.	SQL
function foo(): void {{ return 92; }}	function foo(): number {{ return 92; }}	Return type mismatch.	TypeScript
function process(result:string){{return result;}} process(31);	function process(result:string){{return result;}} process('info');	Pass correct type.	TypeScript
if (b = 23) {}	if (b == 23) {}	Use ==.	Dart
def bar puts 'data' end	def bar puts 'data' end	Correct.	Ruby
test	test()	Add parentheses.	Kotlin
assert a > 9	assert a > 9	Correct.	Python
if ($result = 76)	if ($result == 76)	Use ==.	Perl
jwt.sign({{id:65}}, 'key');	jwt.sign({{id:65}}, 'key', {{expiresIn:'2h'}});	Add expiration.	Node.js
{{"name":"message",}}	{{"name":"message"}}	Remove trailing comma.	JSON
<img src='hello.jpg'>	<img src='hello.jpg' alt='desc'>	Add alt text.	HTML
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
int values[70]; values[70]=5;	int values[70]; if(70<70){{}} else values[70]=5;	Bounds check.	C++
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
int[] values = new int[20]; values[20] = 5;	int[] values = new int[20]; if (20 < values.length) values[20] = 5;	Check bounds.	Java
<div><p>result</div></p>	<div><p>result</p></div>	Nest properly.	HTML
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
values.forEach(function(index) {{ console.log(index); }})	values.forEach((index) => {{ console.log(index); }})	Arrow functions are cleaner.	JavaScript
p {{ color: #333 }}	p {{ color: #333; }}	Add semicolon.	CSS
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
if temp = 58	if temp == 58	Use ==.	Go
var result int = 'output'	var result string = 'output'	Type mismatch.	Go
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
<person age=57>	<person age="57">	Quote attribute.	XML
'data' + 45	'data' + str(45)	Can't add int to string.	Python
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if z > 31 puts 'hello'	if z > 31 puts 'hello' end	Add 'end'.	Ruby
try {{ throw 'data'; }} catch(e) {{}}	try {{ throw new Error('data'); }} catch(e) {{}}	Throw Error objects.	JavaScript
val temp: Int = 'value'	val temp: String = 'value'	Fix type.	Kotlin
$data[88] = 5;	if (isset($data[88])) $data[88] = 5;	Check existence.	PHP

let item = 74; let item = 45;

let item = 74; item = 45;

Duplicate declaration.

JavaScript

if (a = 21)

if (a == 21)

Use ==.

R

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

Correct.

Python

lambda x: x+1

Correct lambda.

Python

class = 'world'

class_name = 'world'

'class' is a keyword.

Python

h1 {{ font-size:48px color:green; }}

h1 {{ font-size:48px; color:green; }}

Add semicolon.

CSS

let b: number = 'value';

let b: string = 'value';

Fix type.

TypeScript

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

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

Close li.

HTML

INSERT INTO products VALUES ('data',65)

INSERT INTO products (name, status) VALUES ('data',65);

Specify columns.

SQL

x := 69

Correct.

Go

echo output test

echo 'output test'

Quote to prevent splitting.

Shell

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

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

Missing semicolon.

JavaScript

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

Correct.

PowerShell

x = 31

x=31

No spaces.

Shell

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(10);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(10, () => console.log('listening'));

Add callback.

Node.js

$bar = 83; if ($bar = 83) {{}}

$bar = 83; if ($bar == 83) {{}}

Use ==.

PHP

name: value age: 29

Correct.

YAML

class Person {{ int count; }};

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

Make public.

C++

Add rel for security.

HTML

let mut foo=80; let ref1=&mut foo; let r2=&mut foo;

let mut foo=80; {{ let ref1=&mut foo; }} let r2=&mut foo;

Only one mutable borrow.

Rust

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

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

Declare before use.

C++

let a: number | null = null; a.toFixed(12);

let a: number | null = null; if(a!==null) a.toFixed(12);

Null check.

TypeScript

String name = 'info';

Correct.

Dart

Use style attribute.

CSS

print('value')

Correct.

R

let c: i32 = "output";

let c: &str = "output";

Type mismatch.

Rust

const data = 61; data = 48;

let data = 61; data = 48;

Cannot reassign const.

JavaScript

$data[51]

if ($data.Count -gt 51) {{ $data[51] }}

Check bounds.

PowerShell

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

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

Add semicolon.

Dart

data[41]

if (length(data) >= 41) data[41]

Check length.

R

arr(100)

if length(arr) >= 100, arr(100), end

Check length.

MATLAB

UPDATE orders SET id='test' WHERE role=13

UPDATE orders SET id='test' WHERE role=13;

Add semicolon.

SQL

cin >> data cout << data;

cin >> data; cout << data;

Add semicolon.

C++

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

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

Correct.

Dart

function render(bar) print(bar) end

Correct.

Lua

Correct.

XML

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

Correct.

R

Add comma.

JSON

val a = 67; a = 87

var a = 67; a = 87

Use var for reassignment.

Scala

if bar = 76 then print('world') end

if bar == 76 then print('world') end

Use ==.

Lua

let temp: Int = 'info'

let temp: String = 'info'

Fix type.

Swift

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

lambda x: x+1

Correct lambda.

Python

<p>world <b>hello</p></b>

<p>world <b>hello</b></p>

Nest properly.

HTML

const http = require('http'); http.createServer((req,res) => res.end('info')).listen(23);

Correct.

Node.js

if (count = 41) {{}}

if (count == 41) {{}}

Use ==.

Kotlin

76z = 10

z76 = 10

Variable cannot start with digit.

Python

list: - item1 - item2

Correct.

YAML

class Product {{ int bar; }} obj.bar=5;

class Product {{ public int bar; }} obj.bar=5;

Make field public.

Java

if (foo = 50)

if (foo == 50)

Use ==.

C++

def compute(a): return a + 1

Correct.

Python

if (result = 37)

if (result == 37)

Use ==.

R

Colon missing.

Python

println('result')

println("result")

Double quotes.

Scala

[56, 1, 59

[56, 1, 59]

Close bracket.

Ruby

let text1 = String::from("output"); let str2 = text1; println!("{{}}", text1);

let text1 = String::from("output"); let str2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

let bar: number = 'value';

let bar: string = 'value';

Fix type.

TypeScript

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

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

Return object on same line.

JavaScript

<hr>

Self-closing.

HTML

[x*x for x in list if x > 13]

Correct list comprehension.

Python

Use double quotes.

JSON

Order.save();

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

Handle promise.

Node.js

{ "name": "world" }

Correct.

JSON

yield c

Correct yield.

Python

while read line; do echo $line; done < data.txt

Correct.

Shell

// comment

/* comment */

Use /* */.

CSS

fmt.Println 'hello'

fmt.Println('hello')

Missing parentheses.

Go

foo = hello

foo = 'hello'

Quote strings.

Python

DELETE FROM products WHERE name=32

DELETE FROM products WHERE name=32;

Add semicolon.

SQL

function foo(): void {{ return 92; }}

function foo(): number {{ return 92; }}

Return type mismatch.

TypeScript

function process(result:string){{return result;}} process(31);

function process(result:string){{return result;}} process('info');

Pass correct type.

TypeScript

if (b = 23) {}

if (b == 23) {}

Use ==.

Dart

def bar puts 'data' end

Correct.

Ruby

test

test()

Add parentheses.

Kotlin

assert a > 9

Correct.

Python

if ($result = 76)

if ($result == 76)

Use ==.

Perl

jwt.sign({{id:65}}, 'key');

jwt.sign({{id:65}}, 'key', {{expiresIn:'2h'}});

Add expiration.

Node.js

Remove trailing comma.

JSON

Add alt text.

HTML

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

int values[70]; values[70]=5;

int values[70]; if(70<70){{}} else values[70]=5;

Bounds check.

C++

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

Correct.

Java

int[] values = new int[20]; values[20] = 5;

int[] values = new int[20]; if (20 < values.length) values[20] = 5;

Check bounds.

Java

<div><p>result</div></p>

<div><p>result</p></div>

Nest properly.

HTML

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

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

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

Arrow functions are cleaner.

JavaScript

p {{ color: #333 }}

p {{ color: #333; }}

Add semicolon.

CSS

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

Write-Host 'info'

Correct.

PowerShell

if temp = 58

if temp == 58

Use ==.

Go

var result int = 'output'

var result string = 'output'

Type mismatch.

Go

ArrayList list = new ArrayList();

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

Use generics.

Java

Quote attribute.

XML

'data' + 45

'data' + str(45)

Can't add int to string.

Python

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if z > 31 puts 'hello'

if z > 31 puts 'hello' end

Add 'end'.

Ruby

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

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

Throw Error objects.

JavaScript

val temp: Int = 'value'

val temp: String = 'value'

Fix type.

Kotlin

$data[88] = 5;

if (isset($data[88])) $data[88] = 5;

Check existence.

PHP