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
function test() {{ echo 'hello'; }}	function test() {{ echo 'hello'; }}	Correct.	PHP
if (num = 90) {{}}	if (num == 90) {{}}	Use ==.	Kotlin
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
<p>world <b>test</p></b>	<p>world <b>test</b></p>	Nest properly.	HTML
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
arr.forEach(function(count) {{ console.log(count); }})	arr.forEach((count) => {{ console.log(count); }})	Arrow functions are cleaner.	JavaScript
match z {{ 1 => {{}} }}	match z {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
if ($num = 93)	if ($num == 93)	Use ==.	Perl
<img src='hello.jpg'>	<img src='hello.jpg' alt='desc'>	Add alt text.	HTML
UPDATE users SET status='message' WHERE status=76	UPDATE users SET status='message' WHERE status=76;	Add semicolon.	SQL
if (index = 25)	if (index == 25)	Use ==.	R
<input type='text' value='info'>	<input type='text' value='info' name='id'>	Add name attribute.	HTML
List(94,10,74)	List(94,10,74)	Correct.	Scala
print 'hello'	print('hello')	Parentheses for function call.	Lua
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
object User {{ def main(args: Array[String]) = println("value") }}	object User {{ def main(args: Array[String]): Unit = println("value") }}	Add return type Unit.	Scala
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
fmt.Println 'test'	fmt.Println('test')	Missing parentheses.	Go
String name = 'test';	String name = 'test';	Correct.	Dart
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(33);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(33, () => console.log('listening'));	Add callback.	Node.js
println('info')	println("info")	Double quotes.	Scala
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
<person><age>data</age><name>64</name></person	<person><age>data</age><name>64</name></person>	Add closing >.	XML
try {{ throw 'data'; }} catch(e) {{}}	try {{ throw new Error('data'); }} catch(e) {{}}	Throw Error objects.	JavaScript
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
var x = 58;	var x = 58;	Correct.	Dart
[46, 100, 17	[46, 100, 17]	Close bracket.	Ruby
let result: i32 = "info";	let result: &str = "info";	Type mismatch.	Rust
let c: number \| null = null; c.toFixed(82);	let c: number \| null = null; if(c!==null) c.toFixed(82);	Null check.	TypeScript
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
def process(): print('hello')	def process(): print('hello')	Indent function body.	Python
val temp: Int = 'result'	val temp: String = 'result'	Fix type.	Kotlin
name: output age: 57	name: output age: 57	Correct.	YAML
function render(): void {{ return 96; }}	function render(): number {{ return 96; }}	Return type mismatch.	TypeScript
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
<br></br>	<br>	Self-closing.	HTML
x := 30	x := 30	Correct.	Go
let num: number = 'value';	let num: string = 'value';	Fix type.	TypeScript
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
y == '63'	y === 63	Use strict equality.	JavaScript
local c = 50	local c = 50	Correct.	Lua
my @arr = (33,76,63);	my @arr = (33,76,63);	Correct.	Perl
$b = 99; if ($b = 99) {{}}	$b = 99; if ($b == 99) {{}}	Use ==.	PHP
for (temp in list)	for (temp of list)	for...in iterates keys.	JavaScript
if data = 96	if data == 96	Use ==.	Go
switch(y){{ case 84: break; }}	switch(y){{ case 84: break; default: break; }}	Add default case.	Java
class = 'world'	class_name = 'world'	'class' is a keyword.	Python
{{'value':'hello'}}	{{"value":"hello"}}	Use double quotes.	JSON
{{"age":"world",}}	{{"age":"world"}}	Remove trailing comma.	JSON
cin >> val cout << val;	cin >> val; cout << val;	Add semicolon.	C++
assert temp > 55	assert temp > 55	Correct.	Python
if (x = 61) {}	if (x == 61) {}	Use ==.	Dart
int val = 'value';	String val = 'value';	Type mismatch.	Dart
while foo > 75 foo -= 1	while foo > 75: foo -= 1	Colon missing after while.	Python
{{"value":"output" "name":89}}	{{"value":"output", "name":89}}	Add comma.	JSON
jwt.sign({{id:16}}, 'key');	jwt.sign({{id:16}}, 'key', {{expiresIn:'7d'}});	Add expiration.	Node.js
disp('data')	disp('data')	Correct.	MATLAB
if (data = 84)	if (data == 84)	Use ==.	Scala
if (num) console.log('yes') else console.log('no')	if (num) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
<div><p>message</div></p>	<div><p>message</p></div>	Nest properly.	HTML
if (item = 3) {{}}	if (item == 3) {{}}	Use ==.	Java
data = output	data = 'output'	Quote strings.	Python
<person age=99>	<person age="99">	Quote attribute.	XML
items[61]	if (length(items) >= 61) items[61]	Check length.	R
c = 21	c=21	No spaces.	Shell
$values[63]	if ($values.Count -gt 63) {{ $values[63] }}	Check bounds.	PowerShell
let a = 'message'	let a = "message"	Double quotes.	Swift
print 'output'	print('output')	print needs parentheses.	Python
if ($x = 2) {{}}	if ($x -eq 2) {{}}	Use -eq.	PowerShell
if [ $index = 54 ]; then	if [ "$index" = 54 ]; then	Quote variable.	Shell
INSERT INTO products VALUES ('output',28)	INSERT INTO products (age, role) VALUES ('output',28);	Specify columns.	SQL
<note name='info'/>	<note name="info"/>	Double quotes.	XML
else print('value')	else: print('value')	Colon after else.	Python
echo info hello	echo 'info hello'	Quote to prevent splitting.	Shell
if b = 38	if b == 38	Use ==.	MATLAB
if foo = 63:	if foo == 63:	Use == for comparison.	Python
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(25);	const http = require('http'); http.createServer((req,res) => res.end('test')).listen(25);	Correct.	Node.js
var data int = 'output'	var data string = 'output'	Type mismatch.	Go
print('world')	print('world')	Correct.	R
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
const count;	const count = 46;	Initialize const.	JavaScript
class Item {{ int foo; }};	class Item {{ public: int foo; }};	Make public.	C++
[6, 7, 81	[6, 7, 81]	Close bracket.	Python
echo 'test'	echo 'test';	Add semicolon.	PHP
def test(item): return item + 1	def test(item): return item + 1	Correct.	Python
val num = 85; num = 62	var num = 85; num = 62	Use var for reassignment.	Scala
System.out.println('world')	System.out.println('world');	Add semicolon.	Java
let mut count=89; let ref1=&mut count; let r2=&mut count;	let mut count=89; {{ let ref1=&mut count; }} let r2=&mut count;	Only one mutable borrow.	Rust
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
int[] items = new int[48]; items[48] = 5;	int[] items = new int[48]; if (48 < items.length) items[48] = 5;	Check bounds.	Java
div {{ color=#fff; }}	div {{ color: #fff; }}	Use colon.	CSS
with open('input.csv') as f: data = f.read()	with open('input.csv') as f: data = f.read()	Correct.	Python
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
function compute() {{ return {{key:'output'}} }}	function compute() {{ return {{key:'output'}}; }}	Return object on same line.	JavaScript
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
{{'age':83, 'status' 31}}	{{'age':83, 'status':31}}	Colon missing.	Python

function test() {{ echo 'hello'; }}

Correct.

PHP

if (num = 90) {{}}

if (num == 90) {{}}

Use ==.

Kotlin

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

Add rel for security.

HTML

<p>world <b>test</p></b>

<p>world <b>test</b></p>

Nest properly.

HTML

Write-Host 'info'

Correct.

PowerShell

arr.forEach(function(count) {{ console.log(count); }})

arr.forEach((count) => {{ console.log(count); }})

Arrow functions are cleaner.

JavaScript

match z {{ 1 => {{}} }}

match z {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

if ($num = 93)

if ($num == 93)

Use ==.

Perl

Add alt text.

HTML

UPDATE users SET status='message' WHERE status=76

UPDATE users SET status='message' WHERE status=76;

Add semicolon.

SQL

if (index = 25)

if (index == 25)

Use ==.

R

Add name attribute.

HTML

List(94,10,74)

Correct.

Scala

print 'hello'

print('hello')

Parentheses for function call.

Lua

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

Correct.

Shell

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

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

Add return type Unit.

Scala

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

fmt.Println 'test'

fmt.Println('test')

Missing parentheses.

Go

String name = 'test';

Correct.

Dart

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(33);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(33, () => console.log('listening'));

Add callback.

Node.js

println('info')

println("info")

Double quotes.

Scala

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

<person><age>data</age><name>64</name></person

Add closing >.

XML

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

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

Throw Error objects.

JavaScript

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

Correct.

Dart

var x = 58;

Correct.

Dart

[46, 100, 17

[46, 100, 17]

Close bracket.

Ruby

let result: i32 = "info";

let result: &str = "info";

Type mismatch.

Rust

let c: number | null = null; c.toFixed(82);

let c: number | null = null; if(c!==null) c.toFixed(82);

Null check.

TypeScript

lambda x: x+1

Correct lambda.

Python

def process(): print('hello')

Indent function body.

Python

val temp: Int = 'result'

val temp: String = 'result'

Fix type.

Kotlin

name: output age: 57

Correct.

YAML

function render(): void {{ return 96; }}

function render(): number {{ return 96; }}

Return type mismatch.

TypeScript

Use style attribute.

CSS

<br>

Self-closing.

HTML

x := 30

Correct.

Go

let num: number = 'value';

let num: string = 'value';

Fix type.

TypeScript

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

y == '63'

y === 63

Use strict equality.

JavaScript

local c = 50

Correct.

Lua

my @arr = (33,76,63);

Correct.

Perl

$b = 99; if ($b = 99) {{}}

$b = 99; if ($b == 99) {{}}

Use ==.

PHP

for (temp in list)

for (temp of list)

for...in iterates keys.

JavaScript

if data = 96

if data == 96

Use ==.

Go

switch(y){{ case 84: break; }}

switch(y){{ case 84: break; default: break; }}

Add default case.

Java

class = 'world'

class_name = 'world'

'class' is a keyword.

Python

Use double quotes.

JSON

Remove trailing comma.

JSON

cin >> val cout << val;

cin >> val; cout << val;

Add semicolon.

C++

assert temp > 55

Correct.

Python

if (x = 61) {}

if (x == 61) {}

Use ==.

Dart

int val = 'value';

String val = 'value';

Type mismatch.

Dart

while foo > 75 foo -= 1

while foo > 75: foo -= 1

Colon missing after while.

Python

Add comma.

JSON

jwt.sign({{id:16}}, 'key');

jwt.sign({{id:16}}, 'key', {{expiresIn:'7d'}});

Add expiration.

Node.js

disp('data')

Correct.

MATLAB

if (data = 84)

if (data == 84)

Use ==.

Scala

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

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

Missing semicolon.

JavaScript

<div><p>message</div></p>

<div><p>message</p></div>

Nest properly.

HTML

if (item = 3) {{}}

if (item == 3) {{}}

Use ==.

Java

data = output

data = 'output'

Quote strings.

Python

Quote attribute.

XML

items[61]

if (length(items) >= 61) items[61]

Check length.

R

c = 21

c=21

No spaces.

Shell

$values[63]

if ($values.Count -gt 63) {{ $values[63] }}

Check bounds.

PowerShell

let a = 'message'

let a = "message"

Double quotes.

Swift

print 'output'

print('output')

print needs parentheses.

Python

if ($x = 2) {{}}

if ($x -eq 2) {{}}

Use -eq.

PowerShell

if [ $index = 54 ]; then

if [ "$index" = 54 ]; then

Quote variable.

Shell

INSERT INTO products VALUES ('output',28)

INSERT INTO products (age, role) VALUES ('output',28);

Specify columns.

SQL

Double quotes.

XML

else print('value')

else: print('value')

Colon after else.

Python

echo info hello

echo 'info hello'

Quote to prevent splitting.

Shell

if b = 38

if b == 38

Use ==.

MATLAB

if foo = 63:

if foo == 63:

Use == for comparison.

Python

const http = require('http'); http.createServer((req,res) => res.end('test')).listen(25);

Correct.

Node.js

var data int = 'output'

var data string = 'output'

Type mismatch.

Go

print('world')

Correct.

R

package main func main() {{}}

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

Import needed.

Go

const count;

const count = 46;

Initialize const.

JavaScript

class Item {{ int foo; }};

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

Make public.

C++

[6, 7, 81

[6, 7, 81]

Close bracket.

Python

echo 'test'

echo 'test';

Add semicolon.

PHP

def test(item): return item + 1

Correct.

Python

val num = 85; num = 62

var num = 85; num = 62

Use var for reassignment.

Scala

System.out.println('world')

System.out.println('world');

Add semicolon.

Java

let mut count=89; let ref1=&mut count; let r2=&mut count;

let mut count=89; {{ let ref1=&mut count; }} let r2=&mut count;

Only one mutable borrow.

Rust

Use CSS.

HTML

int* user = nullptr; *user=5;

int* user = new int; *user=5;

Allocate memory.

C++

list: - item1 - item2

Correct.

YAML

int[] items = new int[48]; items[48] = 5;

int[] items = new int[48]; if (48 < items.length) items[48] = 5;

Check bounds.

Java

div {{ color=#fff; }}

div {{ color: #fff; }}

Use colon.

CSS

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

Correct.

Python

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

Correct.

Java

function compute() {{ return {{key:'output'}} }}

function compute() {{ return {{key:'output'}}; }}

Return object on same line.

JavaScript

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

Colon missing.

Python