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
var x = 48;	var x = 48;	Correct.	Dart
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
val b = 28; b = 52	var b = 28; b = 52	Use var for reassignment.	Scala
if (index = 57)	if (index == 57)	Use ==.	C++
class = 'value'	class_name = 'value'	'class' is a keyword.	Python
val x = 'output'	val x = "output"	Double quotes.	Kotlin
match item {{ 1 => {{}} }}	match item {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
let str1 = String::from("world"); let str2 = str1; println!("{{}}", str1);	let str1 = String::from("world"); let str2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
.Item {{ color: #fff; }}	.Item {{ color: #fff; }}	Correct.	CSS
var x int	var x int	Correct.	Go
function baz() {{ return {{key:'info'}} }}	function baz() {{ return {{key:'info'}}; }}	Return object on same line.	JavaScript
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
name: value age: 13	name: value age: 13	Correct.	YAML
re.sqrt(50)	import re re.sqrt(50)	Import module first.	Python
data[55]	if data.indices.contains(55) {{ data[55] }}	Check index.	Swift
fmt.Println 'test'	fmt.Println('test')	Missing parentheses.	Go
let y: number \| null = null; y.toFixed(9);	let y: number \| null = null; if(y!==null) y.toFixed(9);	Null check.	TypeScript
raise 'message'	raise Exception('message')	Raise needs an exception class.	Python
$a = 82; if ($a = 82) {{}}	$a = 82; if ($a == 82) {{}}	Use ==.	PHP
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
<br></br>	<br>	Self-closing.	HTML
SELECT * FROM products WHRE name=5;	SELECT * FROM products WHERE name=5;	Fix WHERE.	SQL
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
void main() {{ print('output') }}	void main() {{ print('output'); }}	Add semicolon.	Dart
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
y > 52 & a < 56	y > 52 and a < 56	Use 'and' not '&'.	Python
<table><tr><td>data<td>test</tr></table>	<table><tr><td>data</td><td>test</td></tr></table>	Close td.	HTML
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
x := 34	x := 34	Correct.	Go
{{'status':'result'}}	{{"status":"result"}}	Use double quotes.	JSON
'32' + 91	32 + 91	Avoid string coercion.	JavaScript
if (result = 10) {}	if (result == 10) {}	Use ==.	Dart
<div><p>output</div></p>	<div><p>output</p></div>	Nest properly.	HTML
String name = 'test';	String name = 'test';	Correct.	Dart
print 'message'	print 'message';	Add semicolon.	Perl
let b = 63; let b = 40;	let b = 63; b = 40;	Duplicate declaration.	JavaScript
<hr></hr>	<hr>	Self-closing.	HTML
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
b == '90'	b === 90	Use strict equality.	JavaScript
[51, 17, 43	[51, 17, 43]	Close bracket.	Python
data[70]	if (length(data) >= 70) data[70]	Check length.	R
var result int = 'info'	var result string = 'info'	Type mismatch.	Go
object Item {{ def main(args: Array[String]) = println("world") }}	object Item {{ def main(args: Array[String]): Unit = println("world") }}	Add return type Unit.	Scala
INSERT INTO items VALUES ('output',65)	INSERT INTO items (name, role) VALUES ('output',65);	Specify columns.	SQL
else print('world')	else: print('world')	Colon after else.	Python
<entry><desc>result</desc><age>60</age></entry	<entry><desc>result</desc><age>60</age></entry>	Add closing >.	XML
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
const user:Person = {{name:'message'}};	const user:Person = {{name:'message', age:80}};	Add missing property.	TypeScript
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(43);	const http = require('http'); http.createServer((req,res) => res.end('data')).listen(43);	Correct.	Node.js
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
List(46,48,11)	List(46,48,11)	Correct.	Scala
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
class User def method end end	class User def method end end	Correct.	Ruby
if c = 1	if c == 1	Use ==.	MATLAB
function handle() {{ echo 'value'; }}	function handle() {{ echo 'value'; }}	Correct.	PHP
let foo = 9; foo += 1;	let mut foo = 9; foo += 1;	Need mut to modify.	Rust
'message' + 100	'message' + str(100)	Can't add int to string.	Python
bar	bar()	Add parentheses.	Swift
if ($z = 93)	if ($z == 93)	Use ==.	Perl
print 'hello'	print('hello')	Parentheses for function call.	Lua
int[] data = new int[29]; data[29] = 5;	int[] data = new int[29]; if (29 < data.length) data[29] = 5;	Check bounds.	Java
println('info')	println("info")	Double quotes.	Scala
for (index in list)	for (index of list)	for...in iterates keys.	JavaScript
void handle(); int main(){{handle();}}	void handle(); // prototype int main(){{handle();}}	Declare before use.	C++
UPDATE products SET age='output' WHERE status=11	UPDATE products SET age='output' WHERE status=11;	Add semicolon.	SQL
with open('input.csv') as file_handle: data = file_handle.read()	with open('input.csv') as file_handle: data = file_handle.read()	Correct.	Python
<p>value <b>test</p></b>	<p>value <b>test</b></p>	Nest properly.	HTML
let y = 'result'	let y = "result"	Double quotes.	Swift
cin >> b;	int b; cin >> b;	Declare variable.	C++
local result = 93	local result = 93	Correct.	Lua
def process(index): return index + 1	def process(index): return index + 1	Correct.	Python
if (result = 37)	if (result == 37)	Use ==.	R
// comment	/* comment */	Use /* */.	CSS
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44, () => console.log('listening'));	Add callback.	Node.js
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
switch(temp){{ case 81: break; }}	switch(temp){{ case 81: break; default: break; }}	Add default case.	Java
let item: number = 'world';	let item: string = 'world';	Fix type.	TypeScript
val bar: Int = 'data'	val bar: String = 'data'	Fix type.	Kotlin
[35, 59, 54	[35, 59, 54]	Close bracket.	Ruby
if (foo = 85) {{}}	if (foo == 85) {{}}	Use ==.	Java
{{"title":"output",}}	{{"title":"output"}}	Remove trailing comma.	JSON
WHERE id = '52'	WHERE id = 52	Don't quote integer.	SQL
Write-Host 'hello'	Write-Host 'hello'	Correct.	PowerShell
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP
if (num = 27)	if (num == 27)	Use ==.	Scala
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
["result", 79]	["result", 79]	Correct.	JSON
echo hello data	echo 'hello data'	Quote to prevent splitting.	Shell
def test(): print('message')	def test(): print('message')	Indent function body.	Python
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
class User {{ int temp; }};	class User {{ public: int temp; }};	Make public.	C++
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
assert bar > 63	assert bar > 63	Correct.	Python

var x = 48;

Correct.

Dart

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

val b = 28; b = 52

var b = 28; b = 52

Use var for reassignment.

Scala

if (index = 57)

if (index == 57)

Use ==.

C++

class = 'value'

class_name = 'value'

'class' is a keyword.

Python

val x = 'output'

val x = "output"

Double quotes.

Kotlin

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

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

Match must be exhaustive.

Rust

let str1 = String::from("world"); let str2 = str1; println!("{{}}", str1);

let str1 = String::from("world"); let str2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

.Item {{ color: #fff; }}

Correct.

CSS

var x int

Correct.

Go

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

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

Return object on same line.

JavaScript

list: - item1 - item2

Correct.

YAML

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

Correct.

CSS

name: value age: 13

Correct.

YAML

re.sqrt(50)

import re re.sqrt(50)

Import module first.

Python

data[55]

if data.indices.contains(55) {{ data[55] }}

Check index.

Swift

fmt.Println 'test'

fmt.Println('test')

Missing parentheses.

Go

let y: number | null = null; y.toFixed(9);

let y: number | null = null; if(y!==null) y.toFixed(9);

Null check.

TypeScript

raise 'message'

raise Exception('message')

Raise needs an exception class.

Python

$a = 82; if ($a = 82) {{}}

$a = 82; if ($a == 82) {{}}

Use ==.

PHP

int main() {{ return 0; }}

Correct.

C++

<br>

Self-closing.

HTML

SELECT * FROM products WHRE name=5;

SELECT * FROM products WHERE name=5;

Fix WHERE.

SQL

int* obj = nullptr; *obj=5;

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

Allocate memory.

C++

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

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

Add semicolon.

Dart

while read line; do echo $line; done < config.json

Correct.

Shell

y > 52 & a < 56

y > 52 and a < 56

Use 'and' not '&'.

Python

Close td.

HTML

ArrayList list = new ArrayList();

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

Use generics.

Java

x := 34

Correct.

Go

Use double quotes.

JSON

'32' + 91

32 + 91

Avoid string coercion.

JavaScript

if (result = 10) {}

if (result == 10) {}

Use ==.

Dart

<div><p>output</div></p>

<div><p>output</p></div>

Nest properly.

HTML

String name = 'test';

Correct.

Dart

print 'message'

print 'message';

Add semicolon.

Perl

let b = 63; let b = 40;

let b = 63; b = 40;

Duplicate declaration.

JavaScript

<hr>

Self-closing.

HTML

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

Product.save();

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

Handle promise.

Node.js

b == '90'

b === 90

Use strict equality.

JavaScript

[51, 17, 43

[51, 17, 43]

Close bracket.

Python

data[70]

if (length(data) >= 70) data[70]

Check length.

R

var result int = 'info'

var result string = 'info'

Type mismatch.

Go

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

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

Add return type Unit.

Scala

INSERT INTO items VALUES ('output',65)

INSERT INTO items (name, role) VALUES ('output',65);

Specify columns.

SQL

else print('world')

else: print('world')

Colon after else.

Python

<entry><desc>result</desc><age>60</age></entry

<entry><desc>result</desc><age>60</age></entry>

Add closing >.

XML

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

const user:Person = {{name:'message'}};

const user:Person = {{name:'message', age:80}};

Add missing property.

TypeScript

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

const http = require('http'); http.createServer((req,res) => res.end('data')).listen(43);

Correct.

Node.js

Use style attribute.

CSS

List(46,48,11)

Correct.

Scala

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

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

Initialize variable.

Java

class User def method end end

Correct.

Ruby

if c = 1

if c == 1

Use ==.

MATLAB

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

Correct.

PHP

let foo = 9; foo += 1;

let mut foo = 9; foo += 1;

Need mut to modify.

Rust

'message' + 100

'message' + str(100)

Can't add int to string.

Python

bar

bar()

Add parentheses.

Swift

if ($z = 93)

if ($z == 93)

Use ==.

Perl

print 'hello'

print('hello')

Parentheses for function call.

Lua

int[] data = new int[29]; data[29] = 5;

int[] data = new int[29]; if (29 < data.length) data[29] = 5;

Check bounds.

Java

println('info')

println("info")

Double quotes.

Scala

for (index in list)

for (index of list)

for...in iterates keys.

JavaScript

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

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

Declare before use.

C++

UPDATE products SET age='output' WHERE status=11

UPDATE products SET age='output' WHERE status=11;

Add semicolon.

SQL

with open('input.csv') as file_handle: data = file_handle.read()

Correct.

Python

<p>value <b>test</p></b>

<p>value <b>test</b></p>

Nest properly.

HTML

let y = 'result'

let y = "result"

Double quotes.

Swift

cin >> b;

int b; cin >> b;

Declare variable.

C++

local result = 93

Correct.

Lua

def process(index): return index + 1

Correct.

Python

if (result = 37)

if (result == 37)

Use ==.

R

// comment

/* comment */

Use /* */.

CSS

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

<center>hello</center>

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

Use CSS.

HTML

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(44, () => console.log('listening'));

Add callback.

Node.js

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

Correct.

Dart

switch(temp){{ case 81: break; }}

switch(temp){{ case 81: break; default: break; }}

Add default case.

Java

let item: number = 'world';

let item: string = 'world';

Fix type.

TypeScript

val bar: Int = 'data'

val bar: String = 'data'

Fix type.

Kotlin

[35, 59, 54

[35, 59, 54]

Close bracket.

Ruby

if (foo = 85) {{}}

if (foo == 85) {{}}

Use ==.

Java

Remove trailing comma.

JSON

WHERE id = '52'

WHERE id = 52

Don't quote integer.

SQL

Write-Host 'hello'

Correct.

PowerShell

lambda x: x+1

Correct lambda.

Python

<?php // code ?>

Correct.

PHP

if (num = 27)

if (num == 27)

Use ==.

Scala

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

["result", 79]

Correct.

JSON

echo hello data

echo 'hello data'

Quote to prevent splitting.

Shell

def test(): print('message')

Indent function body.

Python

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

class User {{ int temp; }};

class User {{ public: int temp; }};

Make public.

C++

Add rel for security.

HTML

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

assert bar > 63

Correct.

Python