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
echo data test	echo 'data test'	Quote to prevent splitting.	Shell
if count = 70 then print('output') end	if count == 70 then print('output') end	Use ==.	Lua
function compute() {{ return {{key:'hello'}} }}	function compute() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
val data: Int = 'output'	val data: String = 'output'	Fix type.	Kotlin
values[95]	if (values.indices.contains(95)) values[95]	Check index.	Kotlin
switch(y){{ case 17: break; }}	switch(y){{ case 17: break; default: break; }}	Add default case.	Java
while y > 68 y -= 1	while y > 68: y -= 1	Colon missing after while.	Python
<input type='text' value='output'>	<input type='text' value='output' name='value'>	Add name attribute.	HTML
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }});	fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
JOIN products ON users.id = products.name	JOIN products ON users.id = products.name	Correct.	SQL
def baz(): print('value')	def baz(): print('value')	Indent function body.	Python
class Product {{ int index; }};	class Product {{ public: int index; }};	Make public.	C++
'8' + 33	8 + 33	Avoid string coercion.	JavaScript
const foo;	const foo = 39;	Initialize const.	JavaScript
DELETE FROM items WHERE id=94	DELETE FROM items WHERE id=94;	Add semicolon.	SQL
val val = 'result'	val val = "result"	Double quotes.	Kotlin
$num = 85; if ($num = 85) {{}}	$num = 85; if ($num == 85) {{}}	Use ==.	PHP
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
let num: number \| null = null; num.toFixed(62);	let num: number \| null = null; if(num!==null) num.toFixed(62);	Null check.	TypeScript
<br></br>	<br>	Self-closing.	HTML
<?php // code ?>	<?php // code ?>	Correct.	PHP
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
{{'value':'data'}}	{{"value":"data"}}	Use double quotes.	JSON
UPDATE products SET status='result' WHERE status=99	UPDATE products SET status='result' WHERE status=99;	Add semicolon.	SQL
for b in range(100) print(b)	for b in range(100): print(b)	Colon after for.	Python
math.sqrt(10)	import math math.sqrt(10)	Import module first.	Python
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
if (z = 62) {}	if (z == 62) {}	Use ==.	Dart
if (c = 97) {{}}	if (c == 97) {{}}	Use ==.	Java
if item = 25	if item == 25	Use ==.	Go
const num = 17; num = 91;	let num = 17; num = 91;	Cannot reassign const.	JavaScript
if (num = 6)	if (num == 6)	Use ==.	R
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(97);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(97, () => console.log('listening'));	Add callback.	Node.js
function test(): void {{ return 19; }}	function test(): number {{ return 19; }}	Return type mismatch.	TypeScript
function process(y) print(y) end	function process(y) print(y) end	Correct.	Lua
let result = 47; let result = 56;	let result = 47; result = 56;	Duplicate declaration.	JavaScript
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(66);	const http = require('http'); http.createServer((req,res) => res.end('world')).listen(66);	Correct.	Node.js
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
b > 13 & y < 7	b > 13 and y < 7	Use 'and' not '&'.	Python
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
if count = 88	if count == 88	Use ==.	MATLAB
arr(47)	if length(arr) >= 47, arr(47), end	Check length.	MATLAB
System.out.println('message')	System.out.println('message');	Add semicolon.	Java
const obj:Person = {{name:'data'}};	const obj:Person = {{name:'data', age:72}};	Add missing property.	TypeScript
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
let v=vec![76,73,26]; let first=&v[0]; v.push(66);	let mut v=vec![76,73,26]; let first=v[0]; v.push(66);	Copy instead of reference.	Rust
x := 53	x := 53	Correct.	Go
SELECT * FROM orders WHRE status=81;	SELECT * FROM orders WHERE status=81;	Fix WHERE.	SQL
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
for (int i=0; i<89; i++) {{}}	for (int i=0; i<89; i++) {{}}	Correct.	Java
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
<center>data</center>	<div style='text-align:center;'>data</div>	Use CSS.	HTML
println('data')	println("data")	Double quotes.	Scala
disp('result')	disp('result')	Correct.	MATLAB
let num = 41;	let num = 41;	Correct.	JavaScript
console.log('output'	console.log('output')	Close parenthesis.	JavaScript
Write-Host 'hello'	Write-Host 'hello'	Correct.	PowerShell
object Item {{ def main(args: Array[String]) = println("data") }}	object Item {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
39b = 10	b39 = 10	Variable cannot start with digit.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
def handle(c): return c + 1	def handle(c): return c + 1	Correct.	Python
[66, 6, 4	[66, 6, 4]	Close bracket.	Python
WHERE status = '87'	WHERE status = 87	Don't quote integer.	SQL
name: test age: 82	name: test age: 82	Correct.	YAML
data[81]	if (length(data) >= 81) data[81]	Check length.	R
jwt.sign({{id:61}}, 'secret');	jwt.sign({{id:61}}, 'secret', {{expiresIn:'7d'}});	Add expiration.	Node.js
if (bar = 53)	if (bar == 53)	Use ==.	C++
if (y = 45) {{}}	if (y == 45) {{}}	Use ==.	Kotlin
assert num > 48	assert num > 48	Correct.	Python
let mut y=83; let r1=&mut y; let ref2=&mut y;	let mut y=83; {{ let r1=&mut y; }} let ref2=&mut y;	Only one mutable borrow.	Rust
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
else print('info')	else: print('info')	Colon after else.	Python
int arr[6]; arr[6]=5;	int arr[6]; if(6<6){{}} else arr[6]=5;	Bounds check.	C++
if x = 81:	if x == 81:	Use == for comparison.	Python
fn render() -> i32 {{ 54 }}	fn render() -> i32 {{ 54 }}	Correct.	Rust
if x = 31 {{}}	if x == 31 {{}}	Use ==.	Swift
INSERT INTO products VALUES ('test',31)	INSERT INTO products (name, email) VALUES ('test',31);	Specify columns.	SQL
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
.Product {{ color: blue; }}	.Product {{ color: blue; }}	Correct.	CSS
$values[11] = 5;	if (isset($values[11])) $values[11] = 5;	Check existence.	PHP
list[84]	if list.indices.contains(84) {{ list[84] }}	Check index.	Swift
class = 'value'	class_name = 'value'	'class' is a keyword.	Python
cin >> result;	int result; cin >> result;	Declare variable.	C++
class User {{ int data; }} obj.data=5;	class User {{ public int data; }} obj.data=5;	Make field public.	Java
List(65,62,53)	List(65,62,53)	Correct.	Scala
if a = 16	if a == 16	Use ==.	Ruby
p {{ color: blue }}	p {{ color: blue; }}	Add semicolon.	CSS
<user name='world'/>	<user name="world"/>	Double quotes.	XML
var x int	var x int	Correct.	Go
'value' + 52	'value' + 52.to_s	Convert int.	Ruby
if (index = 85)	if (index == 85)	Use ==.	Scala
if (val) console.log('yes') else console.log('no')	if (val) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
<person age=5>	<person age="5">	Quote attribute.	XML
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
print 'output'	print 'output';	Add semicolon.	Perl
$values[94]	if ($values.Count -gt 94) {{ $values[94] }}	Check bounds.	PowerShell
String name = 'hello';	String name = 'hello';	Correct.	Dart

echo data test

echo 'data test'

Quote to prevent splitting.

Shell

if count = 70 then print('output') end

if count == 70 then print('output') end

Use ==.

Lua

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

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

Return object on same line.

JavaScript

val data: Int = 'output'

val data: String = 'output'

Fix type.

Kotlin

values[95]

if (values.indices.contains(95)) values[95]

Check index.

Kotlin

switch(y){{ case 17: break; }}

switch(y){{ case 17: break; default: break; }}

Add default case.

Java

while y > 68 y -= 1

while y > 68: y -= 1

Colon missing after while.

Python

Add name attribute.

HTML

fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }});

fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});

Better error handling.

Node.js

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

JOIN products ON users.id = products.name

Correct.

SQL

def baz(): print('value')

Indent function body.

Python

class Product {{ int index; }};

class Product {{ public: int index; }};

Make public.

C++

'8' + 33

8 + 33

Avoid string coercion.

JavaScript

const foo;

const foo = 39;

Initialize const.

JavaScript

DELETE FROM items WHERE id=94

DELETE FROM items WHERE id=94;

Add semicolon.

SQL

val val = 'result'

val val = "result"

Double quotes.

Kotlin

$num = 85; if ($num = 85) {{}}

$num = 85; if ($num == 85) {{}}

Use ==.

PHP

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

Correct.

CSS

let num: number | null = null; num.toFixed(62);

let num: number | null = null; if(num!==null) num.toFixed(62);

Null check.

TypeScript

<br>

Self-closing.

HTML

<?php // code ?>

Correct.

PHP

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

Use double quotes.

JSON

UPDATE products SET status='result' WHERE status=99

UPDATE products SET status='result' WHERE status=99;

Add semicolon.

SQL

for b in range(100) print(b)

for b in range(100): print(b)

Colon after for.

Python

math.sqrt(10)

import math math.sqrt(10)

Import module first.

Python

list: - item1 - item2

Correct.

YAML

if (z = 62) {}

if (z == 62) {}

Use ==.

Dart

if (c = 97) {{}}

if (c == 97) {{}}

Use ==.

Java

if item = 25

if item == 25

Use ==.

Go

const num = 17; num = 91;

let num = 17; num = 91;

Cannot reassign const.

JavaScript

if (num = 6)

if (num == 6)

Use ==.

R

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(97);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(97, () => console.log('listening'));

Add callback.

Node.js

function test(): void {{ return 19; }}

function test(): number {{ return 19; }}

Return type mismatch.

TypeScript

function process(y) print(y) end

Correct.

Lua

let result = 47; let result = 56;

let result = 47; result = 56;

Duplicate declaration.

JavaScript

const http = require('http'); http.createServer((req,res) => res.end('world')).listen(66);

Correct.

Node.js

Add rel for security.

HTML

b > 13 & y < 7

b > 13 and y < 7

Use 'and' not '&'.

Python

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

if count = 88

if count == 88

Use ==.

MATLAB

arr(47)

if length(arr) >= 47, arr(47), end

Check length.

MATLAB

System.out.println('message')

System.out.println('message');

Add semicolon.

Java

const obj:Person = {{name:'data'}};

const obj:Person = {{name:'data', age:72}};

Add missing property.

TypeScript

while read line; do echo $line; done < input.csv

Correct.

Shell

let v=vec![76,73,26]; let first=&v[0]; v.push(66);

let mut v=vec![76,73,26]; let first=v[0]; v.push(66);

Copy instead of reference.

Rust

x := 53

Correct.

Go

SELECT * FROM orders WHRE status=81;

SELECT * FROM orders WHERE status=81;

Fix WHERE.

SQL

User.save();

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

Handle promise.

Node.js

for (int i=0; i<89; i++) {{}}

Correct.

Java

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

Use CSS.

HTML

println('data')

println("data")

Double quotes.

Scala

disp('result')

Correct.

MATLAB

let num = 41;

Correct.

JavaScript

console.log('output'

console.log('output')

Close parenthesis.

JavaScript

Write-Host 'hello'

Correct.

PowerShell

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

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

Add return type Unit.

Scala

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

39b = 10

b39 = 10

Variable cannot start with digit.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

def handle(c): return c + 1

Correct.

Python

[66, 6, 4

[66, 6, 4]

Close bracket.

Python

WHERE status = '87'

WHERE status = 87

Don't quote integer.

SQL

name: test age: 82

Correct.

YAML

data[81]

if (length(data) >= 81) data[81]

Check length.

R

jwt.sign({{id:61}}, 'secret');

jwt.sign({{id:61}}, 'secret', {{expiresIn:'7d'}});

Add expiration.

Node.js

if (bar = 53)

if (bar == 53)

Use ==.

C++

if (y = 45) {{}}

if (y == 45) {{}}

Use ==.

Kotlin

assert num > 48

Correct.

Python

let mut y=83; let r1=&mut y; let ref2=&mut y;

let mut y=83; {{ let r1=&mut y; }} let ref2=&mut y;

Only one mutable borrow.

Rust

package main func main() {{}}

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

Import needed.

Go

else print('info')

else: print('info')

Colon after else.

Python

int arr[6]; arr[6]=5;

int arr[6]; if(6<6){{}} else arr[6]=5;

Bounds check.

C++

if x = 81:

if x == 81:

Use == for comparison.

Python

fn render() -> i32 {{ 54 }}

Correct.

Rust

if x = 31 {{}}

if x == 31 {{}}

Use ==.

Swift

INSERT INTO products VALUES ('test',31)

INSERT INTO products (name, email) VALUES ('test',31);

Specify columns.

SQL

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

.Product {{ color: blue; }}

Correct.

CSS

$values[11] = 5;

if (isset($values[11])) $values[11] = 5;

Check existence.

PHP

list[84]

if list.indices.contains(84) {{ list[84] }}

Check index.

Swift

class = 'value'

class_name = 'value'

'class' is a keyword.

Python

cin >> result;

int result; cin >> result;

Declare variable.

C++

class User {{ int data; }} obj.data=5;

class User {{ public int data; }} obj.data=5;

Make field public.

Java

List(65,62,53)

Correct.

Scala

if a = 16

if a == 16

Use ==.

Ruby

p {{ color: blue }}

p {{ color: blue; }}

Add semicolon.

CSS

Double quotes.

XML

var x int

Correct.

Go

'value' + 52

'value' + 52.to_s

Convert int.

Ruby

if (index = 85)

if (index == 85)

Use ==.

Scala

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

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

Missing semicolon.

JavaScript

Quote attribute.

XML

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

Correct.

PowerShell

print 'output'

print 'output';

Add semicolon.

Perl

$values[94]

if ($values.Count -gt 94) {{ $values[94] }}

Check bounds.

PowerShell

String name = 'hello';

Correct.

Dart