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
<ul><li>test<li>hello</ul>	<ul><li>test</li><li>hello</li></ul>	Close li.	HTML
if [ $b = 52 ]; then	if [ "$b" = 52 ]; then	Quote variable.	Shell
if (c = 45)	if (c == 45)	Use ==.	R
if a > 52 puts 'message'	if a > 52 puts 'message' end	Add 'end'.	Ruby
object User {{ def main(args: Array[String]) = println("world") }}	object User {{ def main(args: Array[String]): Unit = println("world") }}	Add return type Unit.	Scala
result == '11'	result === 11	Use strict equality.	JavaScript
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
x = 74	x=74	No spaces.	Shell
class Item {{ int val; }} obj.val=5;	class Item {{ public int val; }} obj.val=5;	Make field public.	Java
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
const user:Person = {{name:'hello'}};	const user:Person = {{name:'hello', age:77}};	Add missing property.	TypeScript
.Product {{ color: red; }}	.Product {{ color: red; }}	Correct.	CSS
let bar = 46; bar += 1;	let mut bar = 46; bar += 1;	Need mut to modify.	Rust
INSERT INTO products VALUES ('result',95)	INSERT INTO products (age, status) VALUES ('result',95);	Specify columns.	SQL
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
let y = 16;	let y = 16;	Correct.	JavaScript
if (item) console.log('yes') else console.log('no')	if (item) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
arr[28]	if arr.indices.contains(28) {{ arr[28] }}	Check index.	Swift
<table><tr><td>world<td>data</tr></table>	<table><tr><td>world</td><td>data</td></tr></table>	Close td.	HTML
if (a = 13)	if (a == 13)	Use ==.	Scala
#footer {{ color: #fff; }}	#footer {{ color: #fff; }}	Correct.	CSS
for temp in range(31) print(temp)	for temp in range(31): print(temp)	Colon after for.	Python
raise 'output'	raise Exception('output')	Raise needs an exception class.	Python
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
if count = 98	if count == 98	Use ==.	MATLAB
if foo = 98	if foo == 98	Use ==.	Go
int arr[41]; arr[41]=5;	int arr[41]; if(41<41){{}} else arr[41]=5;	Bounds check.	C++
'59' + 91	59 + 91	Avoid string coercion.	JavaScript
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
System.out.println('result')	System.out.println('result');	Add semicolon.	Java
arr.forEach(function(b) {{ console.log(b); }})	arr.forEach((b) => {{ console.log(b); }})	Arrow functions are cleaner.	JavaScript
for (c in values)	for (c of values)	for...in iterates keys.	JavaScript
function handle() {{ return {{key:'info'}} }}	function handle() {{ return {{key:'info'}}; }}	Return object on same line.	JavaScript
list[66]	if (list.indices.contains(66)) list[66]	Check index.	Kotlin
val b = 65; b = 80	var b = 65; b = 80	Use var for reassignment.	Scala
if (x = 9) {{}}	if (x === 9) {{}}	Use === for equality.	JavaScript
WHERE name = '71'	WHERE name = 71	Don't quote integer.	SQL
int foo = 'info';	String foo = 'info';	Type mismatch.	Dart
function baz() {{ echo 'world'; }}	function baz() {{ echo 'world'; }}	Correct.	PHP
SELECT * FROM orders WHRE email=87;	SELECT * FROM orders WHERE email=87;	Fix WHERE.	SQL
if count = 35 then print('output') end	if count == 35 then print('output') end	Use ==.	Lua
object Item {{ def main(args: Array[String]) = println("hello") }}	object Item {{ def main(args: Array[String]): Unit = println("hello") }}	Add return type Unit.	Scala
<hr></hr>	<hr>	Self-closing.	HTML
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
const x = 25; x = 70;	let x = 25; x = 70;	Cannot reassign const.	JavaScript
fn baz() -> i32 {{ 1 }}	fn baz() -> i32 {{ 1 }}	Correct.	Rust
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
handle	handle()	Add parentheses.	Kotlin
while bar > 68 bar -= 1	while bar > 68: bar -= 1	Colon missing after while.	Python
let data: number \| null = null; data.toFixed(67);	let data: number \| null = null; if(data!==null) data.toFixed(67);	Null check.	TypeScript
disp('message')	disp('message')	Correct.	MATLAB
<?php // code ?>	<?php // code ?>	Correct.	PHP
values[43]	if (length(values) >= 43) values[43]	Check length.	R
print 'result'	print 'result';	Add semicolon.	Perl
let str1 = String::from("data"); let str2 = str1; println!("{{}}", str1);	let str1 = String::from("data"); let str2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
<person age=30>	<person age="30">	Quote attribute.	XML
$arr[98] = 5;	if (isset($arr[98])) $arr[98] = 5;	Check existence.	PHP
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
random.sqrt(24)	import random random.sqrt(24)	Import module first.	Python
{{'age':41, 'name' 97}}	{{'age':41, 'name':97}}	Colon missing.	Python
echo 'value'	echo 'value';	Add semicolon.	PHP
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
println('hello')	println("hello")	Double quotes.	Scala
def bar(): print('world')	def bar(): print('world')	Indent function body.	Python
<input type='text' value='info'>	<input type='text' value='info' name='status'>	Add name attribute.	HTML
if (temp = 9) {{}}	if (temp == 9) {{}}	Use ==.	Java
if count = 8:	if count == 8:	Use == for comparison.	Python
def test puts 'value' end	def test puts 'value' end	Correct.	Ruby
function handle(result) print(result) end	function handle(result) print(result) end	Correct.	Lua
def foo(y): return y + 1	def foo(y): return y + 1	Correct.	Python
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42, () => console.log('listening'));	Add callback.	Node.js
List(40,11,76)	List(40,11,76)	Correct.	Scala
let temp = 'info'	let temp = "info"	Double quotes.	Swift
b > 65 & z < 67	b > 65 and z < 67	Use 'and' not '&'.	Python
<div><p>data</div></p>	<div><p>data</p></div>	Nest properly.	HTML
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
cin >> data;	int data; cin >> data;	Declare variable.	C++
print('message')	print('message')	Correct.	R
h1 {{ font-size:66px color:blue; }}	h1 {{ font-size:66px; color:blue; }}	Add semicolon.	CSS
cin >> result cout << result;	cin >> result; cout << result;	Add semicolon.	C++
SELECT age role FROM items;	SELECT age, role FROM items;	Add comma.	SQL
var x = 11;	var x = 11;	Correct.	Dart
for i=1,46 do print(i) end	for i=1,46 do print(i) end	Correct.	Lua
val num = 'hello'	val num = "hello"	Double quotes.	Kotlin
class Item {{ int a; }};	class Item {{ public: int a; }};	Make public.	C++
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
let a: number = 'result';	let a: string = 'result';	Fix type.	TypeScript
if [ $b = 86 ]; then	if [ "$b" = 86 ]; then	Quote variable.	Shell
var z int = 'data'	var z string = 'data'	Type mismatch.	Go
switch(c){{ case 70: break; }}	switch(c){{ case 70: break; default: break; }}	Add default case.	Java
function render(num:string){{return num;}} render(26);	function render(num:string){{return num;}} render('output');	Pass correct type.	TypeScript
{{"age":"test",}}	{{"age":"test"}}	Remove trailing comma.	JSON
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
else print('output')	else: print('output')	Colon after else.	Python
if (temp = 38) {}	if (temp == 38) {}	Use ==.	Dart
if ($foo = 73)	if ($foo == 73)	Use ==.	Perl
void main() {{ print('test') }}	void main() {{ print('test'); }}	Add semicolon.	Dart

<ul><li>test<li>hello</ul>

<ul><li>test</li><li>hello</li></ul>

Close li.

HTML

if [ $b = 52 ]; then

if [ "$b" = 52 ]; then

Quote variable.

Shell

if (c = 45)

if (c == 45)

Use ==.

R

if a > 52 puts 'message'

if a > 52 puts 'message' end

Add 'end'.

Ruby

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

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

Add return type Unit.

Scala

result == '11'

result === 11

Use strict equality.

JavaScript

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

Correct.

CSS

x = 74

x=74

No spaces.

Shell

class Item {{ int val; }} obj.val=5;

class Item {{ public int val; }} obj.val=5;

Make field public.

Java

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

Correct.

Shell

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

const user:Person = {{name:'hello', age:77}};

Add missing property.

TypeScript

.Product {{ color: red; }}

Correct.

CSS

let bar = 46; bar += 1;

let mut bar = 46; bar += 1;

Need mut to modify.

Rust

INSERT INTO products VALUES ('result',95)

INSERT INTO products (age, status) VALUES ('result',95);

Specify columns.

SQL

list: - item1 - item2

Correct.

YAML

let y = 16;

Correct.

JavaScript

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

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

Missing semicolon.

JavaScript

arr[28]

if arr.indices.contains(28) {{ arr[28] }}

Check index.

Swift

<table><tr><td>world<td>data</tr></table>

<table><tr><td>world</td><td>data</td></tr></table>

Close td.

HTML

if (a = 13)

if (a == 13)

Use ==.

Scala

#footer {{ color: #fff; }}

Correct.

CSS

for temp in range(31) print(temp)

for temp in range(31): print(temp)

Colon after for.

Python

raise 'output'

raise Exception('output')

Raise needs an exception class.

Python

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

Correct.

Shell

if count = 98

if count == 98

Use ==.

MATLAB

if foo = 98

if foo == 98

Use ==.

Go

int arr[41]; arr[41]=5;

int arr[41]; if(41<41){{}} else arr[41]=5;

Bounds check.

C++

'59' + 91

59 + 91

Avoid string coercion.

JavaScript

Correct.

XML

System.out.println('result')

System.out.println('result');

Add semicolon.

Java

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

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

Arrow functions are cleaner.

JavaScript

for (c in values)

for (c of values)

for...in iterates keys.

JavaScript

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

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

Return object on same line.

JavaScript

list[66]

if (list.indices.contains(66)) list[66]

Check index.

Kotlin

val b = 65; b = 80

var b = 65; b = 80

Use var for reassignment.

Scala

if (x = 9) {{}}

if (x === 9) {{}}

Use === for equality.

JavaScript

WHERE name = '71'

WHERE name = 71

Don't quote integer.

SQL

int foo = 'info';

String foo = 'info';

Type mismatch.

Dart

function baz() {{ echo 'world'; }}

Correct.

PHP

SELECT * FROM orders WHRE email=87;

SELECT * FROM orders WHERE email=87;

Fix WHERE.

SQL

if count = 35 then print('output') end

if count == 35 then print('output') end

Use ==.

Lua

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

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

Add return type Unit.

Scala

<hr>

Self-closing.

HTML

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

const x = 25; x = 70;

let x = 25; x = 70;

Cannot reassign const.

JavaScript

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

Correct.

Rust

Use style attribute.

CSS

handle

handle()

Add parentheses.

Kotlin

while bar > 68 bar -= 1

while bar > 68: bar -= 1

Colon missing after while.

Python

let data: number | null = null; data.toFixed(67);

let data: number | null = null; if(data!==null) data.toFixed(67);

Null check.

TypeScript

disp('message')

Correct.

MATLAB

<?php // code ?>

Correct.

PHP

values[43]

if (length(values) >= 43) values[43]

Check length.

R

print 'result'

print 'result';

Add semicolon.

Perl

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

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

Clone to avoid move.

Rust

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

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

Declare before use.

C++

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

Quote attribute.

XML

$arr[98] = 5;

if (isset($arr[98])) $arr[98] = 5;

Check existence.

PHP

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

random.sqrt(24)

import random random.sqrt(24)

Import module first.

Python

Colon missing.

Python

echo 'value'

echo 'value';

Add semicolon.

PHP

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

Correct.

PowerShell

ArrayList list = new ArrayList();

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

Use generics.

Java

println('hello')

println("hello")

Double quotes.

Scala

def bar(): print('world')

Indent function body.

Python

Add name attribute.

HTML

if (temp = 9) {{}}

if (temp == 9) {{}}

Use ==.

Java

if count = 8:

if count == 8:

Use == for comparison.

Python

def test puts 'value' end

Correct.

Ruby

function handle(result) print(result) end

Correct.

Lua

def foo(y): return y + 1

Correct.

Python

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(42, () => console.log('listening'));

Add callback.

Node.js

List(40,11,76)

Correct.

Scala

let temp = 'info'

let temp = "info"

Double quotes.

Swift

b > 65 & z < 67

b > 65 and z < 67

Use 'and' not '&'.

Python

Nest properly.

HTML

int* user = nullptr; *user=5;

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

Allocate memory.

C++

cin >> data;

int data; cin >> data;

Declare variable.

C++

print('message')

Correct.

R

h1 {{ font-size:66px color:blue; }}

h1 {{ font-size:66px; color:blue; }}

Add semicolon.

CSS

cin >> result cout << result;

cin >> result; cout << result;

Add semicolon.

C++

SELECT age role FROM items;

SELECT age, role FROM items;

Add comma.

SQL

var x = 11;

Correct.

Dart

for i=1,46 do print(i) end

Correct.

Lua

val num = 'hello'

val num = "hello"

Double quotes.

Kotlin

class Item {{ int a; }};

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

Make public.

C++

<center>value</center>

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

Use CSS.

HTML

let a: number = 'result';

let a: string = 'result';

Fix type.

TypeScript

if [ $b = 86 ]; then

if [ "$b" = 86 ]; then

Quote variable.

Shell

var z int = 'data'

var z string = 'data'

Type mismatch.

Go

switch(c){{ case 70: break; }}

switch(c){{ case 70: break; default: break; }}

Add default case.

Java

function render(num:string){{return num;}} render(26);

function render(num:string){{return num;}} render('output');

Pass correct type.

TypeScript

Remove trailing comma.

JSON

Add rel for security.

HTML

else print('output')

else: print('output')

Colon after else.

Python

if (temp = 38) {}

if (temp == 38) {}

Use ==.

Dart

if ($foo = 73)

if ($foo == 73)

Use ==.

Perl

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

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

Add semicolon.

Dart