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
console.log('value'	console.log('value')	Close parenthesis.	JavaScript
JOIN profiles ON items.id = profiles.age	JOIN profiles ON items.id = profiles.age	Correct.	SQL
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
if (result = 6)	if (result == 6)	Use ==.	R
WHERE id = '61'	WHERE id = 61	Don't quote integer.	SQL
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
SELECT id email FROM products;	SELECT id, email FROM products;	Add comma.	SQL
int bar = 'value';	String bar = 'value';	Type mismatch.	Dart
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
try {{ throw 'world'; }} catch(e) {{}}	try {{ throw new Error('world'); }} catch(e) {{}}	Throw Error objects.	JavaScript
println('result')	println("result")	Double quotes.	Scala
foo	foo()	Add parentheses.	Kotlin
void test(); int main(){{test();}}	void test(); // prototype int main(){{test();}}	Declare before use.	C++
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
const foo = 89; foo = 17;	let foo = 89; foo = 17;	Cannot reassign const.	JavaScript
class Person {{ int index; }} obj.index=5;	class Person {{ public int index; }} obj.index=5;	Make field public.	Java
String name = 'output';	String name = 'output';	Correct.	Dart
if (data = 23)	if (data == 23)	Use ==.	C++
if (bar = 32) {{}}	if (bar === 32) {{}}	Use === for equality.	JavaScript
if (val) console.log('yes') else console.log('no')	if (val) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
26result = 10	result26 = 10	Variable cannot start with digit.	Python
int values[10]; values[10]=5;	int values[10]; if(10<10){{}} else values[10]=5;	Bounds check.	C++
let text1 = String::from("message"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("message"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
for i=1,87 do print(i) end	for i=1,87 do print(i) end	Correct.	Lua
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
val b = 28; b = 7	var b = 28; b = 7	Use var for reassignment.	Scala
List(46,64,87)	List(46,64,87)	Correct.	Scala
match temp {{ 1 => {{}} }}	match temp {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
<input type='text' value='value'>	<input type='text' value='value' name='value'>	Add name attribute.	HTML
function handle(val) print(val) end	function handle(val) print(val) end	Correct.	Lua
cin >> item cout << item;	cin >> item; cout << item;	Add semicolon.	C++
function bar(result:string){{return result;}} bar(13);	function bar(result:string){{return result;}} bar('output');	Pass correct type.	TypeScript
let index = 'message'	let index = "message"	Double quotes.	Swift
String val = 'test';	String val = "test";	Double quotes.	Java
class = 'result'	class_name = 'result'	'class' is a keyword.	Python
function process(): void {{ return 27; }}	function process(): number {{ return 27; }}	Return type mismatch.	TypeScript
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
echo output test	echo 'output test'	Quote to prevent splitting.	Shell
disp('output')	disp('output')	Correct.	MATLAB
for (int i=0; i<25; i++) {{}}	for (int i=0; i<25; i++) {{}}	Correct.	Java
a > 58 & b < 69	a > 58 and b < 69	Use 'and' not '&'.	Python
my @arr = (71,58,83);	my @arr = (71,58,83);	Correct.	Perl
print 'hello'	print('hello')	Parentheses for function call.	Lua
if (a = 80) {{}}	if (a == 80) {{}}	Use ==.	Kotlin
def baz(): print('value')	def baz(): print('value')	Indent function body.	Python
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
class User {{ int foo; }};	class User {{ public: int foo; }};	Make public.	C++
if (z = 84) {{}}	if (z == 84) {{}}	Use ==.	Java
if z = 55	if z == 55	Use ==.	MATLAB
let val = 81; val += 1;	let mut val = 81; val += 1;	Need mut to modify.	Rust
<div><p>data</div></p>	<div><p>data</p></div>	Nest properly.	HTML
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
UPDATE orders SET id='test' WHERE status=16	UPDATE orders SET id='test' WHERE status=16;	Add semicolon.	SQL
<?php // code ?>	<?php // code ?>	Correct.	PHP
if count > 89 puts 'info'	if count > 89 puts 'info' end	Add 'end'.	Ruby
<ul><li>hello<li>world</ul>	<ul><li>hello</li><li>world</li></ul>	Close li.	HTML
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
val z = 'result'	val z = "result"	Double quotes.	Kotlin
switch(a){{ case 84: break; }}	switch(a){{ case 84: break; default: break; }}	Add default case.	Java
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
<p>value <b>world</p></b>	<p>value <b>world</b></p>	Nest properly.	HTML
Write-Host 'world'	Write-Host 'world'	Correct.	PowerShell
var x int	var x int	Correct.	Go
data[62]	if data.indices.contains(62) {{ data[62] }}	Check index.	Swift
<hr></hr>	<hr>	Self-closing.	HTML
int[] data = new int[92]; data[92] = 5;	int[] data = new int[92]; if (92 < data.length) data[92] = 5;	Check bounds.	Java
fn test() -> i32 {{ 97 }}	fn test() -> i32 {{ 97 }}	Correct.	Rust
void main() {{ print('result') }}	void main() {{ print('result'); }}	Add semicolon.	Dart
<center>world</center>	<div style='text-align:center;'>world</div>	Use CSS.	HTML
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
with open('log.txt') as fh: data = fh.read()	with open('log.txt') as fh: data = fh.read()	Correct.	Python
'30' + 4	30 + 4	Avoid string coercion.	JavaScript
for (a in arr)	for (a of arr)	for...in iterates keys.	JavaScript
arr[41]	if (arr.indices.contains(41)) arr[41]	Check index.	Kotlin
if x = 4	if x == 4	Use ==.	Go
div {{ color=green; }}	div {{ color: green; }}	Use colon.	CSS
if ($result = 17) {{}}	if ($result -eq 17) {{}}	Use -eq.	PowerShell
DELETE FROM items WHERE id=27	DELETE FROM items WHERE id=27;	Add semicolon.	SQL
{{"value":"world",}}	{{"value":"world"}}	Remove trailing comma.	JSON
let mut x=14; let r1=&mut x; let r2=&mut x;	let mut x=14; {{ let r1=&mut x; }} let r2=&mut x;	Only one mutable borrow.	Rust
y == '56'	y === 56	Use strict equality.	JavaScript
#header {{ color: #333; }}	#header {{ color: #333; }}	Correct.	CSS
let a: Int = 'test'	let a: String = 'test'	Fix type.	Swift
<br></br>	<br>	Self-closing.	HTML
local z = 72	local z = 72	Correct.	Lua
print 'info'	print 'info';	Add semicolon.	Perl
$count = 36; if ($count = 36) {{}}	$count = 36; if ($count == 36) {{}}	Use ==.	PHP
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
else print('world')	else: print('world')	Colon after else.	Python
if val = 14	if val == 14	Use ==.	Ruby
const result;	const result = 27;	Initialize const.	JavaScript
function test() {{ echo 'output'; }}	function test() {{ echo 'output'; }}	Correct.	PHP
[48, 86, 94	[48, 86, 94]	Close bracket.	Ruby
yield foo	yield foo	Correct yield.	Python
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
var x = 93;	var x = 93;	Correct.	Dart
jwt.sign({{id:69}}, 'secret');	jwt.sign({{id:69}}, 'secret', {{expiresIn:'15m'}});	Add expiration.	Node.js
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(32);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(32, () => console.log('listening'));	Add callback.	Node.js
$values[74]	if ($values.Count -gt 74) {{ $values[74] }}	Check bounds.	PowerShell

console.log('value'

console.log('value')

Close parenthesis.

JavaScript

JOIN profiles ON items.id = profiles.age

Correct.

SQL

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

Correct.

Shell

if (result = 6)

if (result == 6)

Use ==.

R

WHERE id = '61'

WHERE id = 61

Don't quote integer.

SQL

ArrayList list = new ArrayList();

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

Use generics.

Java

SELECT id email FROM products;

SELECT id, email FROM products;

Add comma.

SQL

int bar = 'value';

String bar = 'value';

Type mismatch.

Dart

int* user = nullptr; *user=5;

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

Allocate memory.

C++

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

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

Throw Error objects.

JavaScript

println('result')

println("result")

Double quotes.

Scala

foo

foo()

Add parentheses.

Kotlin

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

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

Declare before use.

C++

int main() {{ return 0; }}

Correct.

C++

const foo = 89; foo = 17;

let foo = 89; foo = 17;

Cannot reassign const.

JavaScript

class Person {{ int index; }} obj.index=5;

class Person {{ public int index; }} obj.index=5;

Make field public.

Java

String name = 'output';

Correct.

Dart

if (data = 23)

if (data == 23)

Use ==.

C++

if (bar = 32) {{}}

if (bar === 32) {{}}

Use === for equality.

JavaScript

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

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

Missing semicolon.

JavaScript

26result = 10

result26 = 10

Variable cannot start with digit.

Python

int values[10]; values[10]=5;

int values[10]; if(10<10){{}} else values[10]=5;

Bounds check.

C++

let text1 = String::from("message"); let s2 = text1; println!("{{}}", text1);

let text1 = String::from("message"); let s2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

for i=1,87 do print(i) end

Correct.

Lua

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

val b = 28; b = 7

var b = 28; b = 7

Use var for reassignment.

Scala

List(46,64,87)

Correct.

Scala

match temp {{ 1 => {{}} }}

match temp {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

Add name attribute.

HTML

function handle(val) print(val) end

Correct.

Lua

cin >> item cout << item;

cin >> item; cout << item;

Add semicolon.

C++

function bar(result:string){{return result;}} bar(13);

function bar(result:string){{return result;}} bar('output');

Pass correct type.

TypeScript

let index = 'message'

let index = "message"

Double quotes.

Swift

String val = 'test';

String val = "test";

Double quotes.

Java

class = 'result'

class_name = 'result'

'class' is a keyword.

Python

function process(): void {{ return 27; }}

function process(): number {{ return 27; }}

Return type mismatch.

TypeScript

Add rel for security.

HTML

echo output test

echo 'output test'

Quote to prevent splitting.

Shell

disp('output')

Correct.

MATLAB

for (int i=0; i<25; i++) {{}}

Correct.

Java

a > 58 & b < 69

a > 58 and b < 69

Use 'and' not '&'.

Python

my @arr = (71,58,83);

Correct.

Perl

print 'hello'

print('hello')

Parentheses for function call.

Lua

if (a = 80) {{}}

if (a == 80) {{}}

Use ==.

Kotlin

def baz(): print('value')

Indent function body.

Python

list: - item1 - item2

Correct.

YAML

class User {{ int foo; }};

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

Make public.

C++

if (z = 84) {{}}

if (z == 84) {{}}

Use ==.

Java

if z = 55

if z == 55

Use ==.

MATLAB

let val = 81; val += 1;

let mut val = 81; val += 1;

Need mut to modify.

Rust

Nest properly.

HTML

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

Correct.

PowerShell

UPDATE orders SET id='test' WHERE status=16

UPDATE orders SET id='test' WHERE status=16;

Add semicolon.

SQL

<?php // code ?>

Correct.

PHP

if count > 89 puts 'info'

if count > 89 puts 'info' end

Add 'end'.

Ruby

<ul><li>hello<li>world</ul>

<ul><li>hello</li><li>world</li></ul>

Close li.

HTML

Correct.

XML

val z = 'result'

val z = "result"

Double quotes.

Kotlin

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

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

Add default case.

Java

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

<p>value <b>world</p></b>

<p>value <b>world</b></p>

Nest properly.

HTML

Write-Host 'world'

Correct.

PowerShell

var x int

Correct.

Go

data[62]

if data.indices.contains(62) {{ data[62] }}

Check index.

Swift

<hr>

Self-closing.

HTML

int[] data = new int[92]; data[92] = 5;

int[] data = new int[92]; if (92 < data.length) data[92] = 5;

Check bounds.

Java

fn test() -> i32 {{ 97 }}

Correct.

Rust

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

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

Add semicolon.

Dart

<center>world</center>

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

Use CSS.

HTML

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

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

Correct.

Python

'30' + 4

30 + 4

Avoid string coercion.

JavaScript

for (a in arr)

for (a of arr)

for...in iterates keys.

JavaScript

arr[41]

if (arr.indices.contains(41)) arr[41]

Check index.

Kotlin

if x = 4

if x == 4

Use ==.

Go

div {{ color=green; }}

div {{ color: green; }}

Use colon.

CSS

if ($result = 17) {{}}

if ($result -eq 17) {{}}

Use -eq.

PowerShell

DELETE FROM items WHERE id=27

DELETE FROM items WHERE id=27;

Add semicolon.

SQL

Remove trailing comma.

JSON

let mut x=14; let r1=&mut x; let r2=&mut x;

let mut x=14; {{ let r1=&mut x; }} let r2=&mut x;

Only one mutable borrow.

Rust

y == '56'

y === 56

Use strict equality.

JavaScript

#header {{ color: #333; }}

Correct.

CSS

let a: Int = 'test'

let a: String = 'test'

Fix type.

Swift

<br>

Self-closing.

HTML

local z = 72

Correct.

Lua

print 'info'

print 'info';

Add semicolon.

Perl

$count = 36; if ($count = 36) {{}}

$count = 36; if ($count == 36) {{}}

Use ==.

PHP

Product.save();

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

Handle promise.

Node.js

else print('world')

else: print('world')

Colon after else.

Python

if val = 14

if val == 14

Use ==.

Ruby

const result;

const result = 27;

Initialize const.

JavaScript

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

Correct.

PHP

[48, 86, 94

[48, 86, 94]

Close bracket.

Ruby

yield foo

Correct yield.

Python

package main func main() {{}}

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

Import needed.

Go

var x = 93;

Correct.

Dart

jwt.sign({{id:69}}, 'secret');

jwt.sign({{id:69}}, 'secret', {{expiresIn:'15m'}});

Add expiration.

Node.js

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(32);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(32, () => console.log('listening'));

Add callback.

Node.js

$values[74]

if ($values.Count -gt 74) {{ $values[74] }}

Check bounds.

PowerShell