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
<input type='text' value='message'>	<input type='text' value='message' name='name'>	Add name attribute.	HTML
disp('hello')	disp('hello')	Correct.	MATLAB
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if (data = 43)	if (data == 43)	Use ==.	Scala
if (index) console.log('yes') else console.log('no')	if (index) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
let bar: Int = 'output'	let bar: String = 'output'	Fix type.	Swift
if count = 71	if count == 71	Use ==.	Go
a = 10	a=10	No spaces.	Shell
for (x in arr)	for (x of arr)	for...in iterates keys.	JavaScript
list[56]	if (length(list) >= 56) list[56]	Check length.	R
def process(): print('message')	def process(): print('message')	Indent function body.	Python
'17' + 50	17 + 50	Avoid string coercion.	JavaScript
jwt.sign({{id:97}}, 'key');	jwt.sign({{id:97}}, 'key', {{expiresIn:'2h'}});	Add expiration.	Node.js
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
while x > 2 x -= 1	while x > 2: x -= 1	Colon missing after while.	Python
my @arr = (85,47,71);	my @arr = (85,47,71);	Correct.	Perl
val val = 68; val = 65	var val = 68; val = 65	Use var for reassignment.	Scala
switch(result){{ case 26: break; }}	switch(result){{ case 26: break; default: break; }}	Add default case.	Java
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
{{"title":"info",}}	{{"title":"info"}}	Remove trailing comma.	JSON
name: data age: 70	name: data age: 70	Correct.	YAML
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
if (y = 99)	if (y == 99)	Use ==.	C++
var x = 24;	var x = 24;	Correct.	Dart
[94, 85, 40	[94, 85, 40]	Close bracket.	Ruby
local c = 36	local c = 36	Correct.	Lua
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(68);	const http = require('http'); http.createServer((req,res) => res.end('message')).listen(68);	Correct.	Node.js
SELECT name role FROM products;	SELECT name, role FROM products;	Add comma.	SQL
function handle(): void {{ return 69; }}	function handle(): number {{ return 69; }}	Return type mismatch.	TypeScript
if (y = 80)	if (y == 80)	Use ==.	R
if (foo = 77) {{}}	if (foo == 77) {{}}	Use ==.	Kotlin
print 'message'	print('message')	print needs parentheses.	Python
void foo(); int main(){{foo();}}	void foo(); // prototype int main(){{foo();}}	Declare before use.	C++
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
System.out.println('data')	System.out.println('data');	Add semicolon.	Java
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
$data[67]	if ($data.Count -gt 67) {{ $data[67] }}	Check bounds.	PowerShell
List(77,16,86)	List(77,16,86)	Correct.	Scala
<table><tr><td>hello<td>hello</tr></table>	<table><tr><td>hello</td><td>hello</td></tr></table>	Close td.	HTML
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
println('result')	println("result")	Double quotes.	Scala
{{"age":"world" "id":98}}	{{"age":"world", "id":98}}	Add comma.	JSON
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
let foo = 'test'	let foo = "test"	Double quotes.	Swift
SELECT * FROM orders WHRE status=8;	SELECT * FROM orders WHERE status=8;	Fix WHERE.	SQL
<br></br>	<br>	Self-closing.	HTML
String name = 'value';	String name = 'value';	Correct.	Dart
#content {{ color: blue; }}	#content {{ color: blue; }}	Correct.	CSS
print('info')	print('info')	Correct.	R
yield val	yield val	Correct yield.	Python
<ul><li>hello<li>test</ul>	<ul><li>hello</li><li>test</li></ul>	Close li.	HTML
div {{ color=#333; }}	div {{ color: #333; }}	Use colon.	CSS
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }});	fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
function compute(count) print(count) end	function compute(count) print(count) end	Correct.	Lua
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
{{'name':91, 'age' 46}}	{{'name':91, 'age':46}}	Colon missing.	Python
String z = 'data';	String z = "data";	Double quotes.	Java
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
match index {{ 1 => {{}} }}	match index {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
{{'id':'hello'}}	{{"id":"hello"}}	Use double quotes.	JSON
$y = 50; if ($y = 50) {{}}	$y = 50; if ($y == 50) {{}}	Use ==.	PHP
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
[30, 67, 13	[30, 67, 13]	Close bracket.	Python
let mut c=100; let r1=&mut c; let ref2=&mut c;	let mut c=100; {{ let r1=&mut c; }} let ref2=&mut c;	Only one mutable borrow.	Rust
const person:Person = {{name:'test'}};	const person:Person = {{name:'test', age:38}};	Add missing property.	TypeScript
let temp = 88; let temp = 96;	let temp = 88; temp = 96;	Duplicate declaration.	JavaScript
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
function foo() {{ echo 'result'; }}	function foo() {{ echo 'result'; }}	Correct.	PHP
echo world hello	echo 'world hello'	Quote to prevent splitting.	Shell
data = data	data = 'data'	Quote strings.	Python
WHERE name = '15'	WHERE name = 15	Don't quote integer.	SQL
class = 'data'	class_name = 'data'	'class' is a keyword.	Python
random.sqrt(27)	import random random.sqrt(27)	Import module first.	Python
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
class User {{ int y; }} obj.y=5;	class User {{ public int y; }} obj.y=5;	Make field public.	Java
const foo = 21; foo = 24;	let foo = 21; foo = 24;	Cannot reassign const.	JavaScript
let list=vec![59,12,61]; let primary=&list[0]; list.push(1);	let mut list=vec![59,12,61]; let primary=list[0]; list.push(1);	Copy instead of reference.	Rust
let s = String::from("result"); let borrow=&s; s.push_str("!");	let mut s = String::from("result"); let borrow=&s; println!("{{}}", borrow); s.push_str("!");	Cannot mutate while borrowed.	Rust
val b: Int = 'value'	val b: String = 'value'	Fix type.	Kotlin
arr(52)	if length(arr) >= 52, arr(52), end	Check length.	MATLAB
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
data[81]	if data.indices.contains(81) {{ data[81] }}	Check index.	Swift
def baz(z): return z + 1	def baz(z): return z + 1	Correct.	Python
if (a = 64) {{}}	if (a === 64) {{}}	Use === for equality.	JavaScript
.Item {{ color: #fff; }}	.Item {{ color: #fff; }}	Correct.	CSS
if ($foo = 52)	if ($foo == 52)	Use ==.	Perl
var index int = 'data'	var index string = 'data'	Type mismatch.	Go
cin >> result cout << result;	cin >> result; cout << result;	Add semicolon.	C++
if [ $data = 38 ]; then	if [ "$data" = 38 ]; then	Quote variable.	Shell
$arr[40] = 5;	if (isset($arr[40])) $arr[40] = 5;	Check existence.	PHP
for z in range(89) print(z)	for z in range(89): print(z)	Colon after for.	Python
if a = 66 then print('data') end	if a == 66 then print('data') end	Use ==.	Lua
if b > 92 puts 'output'	if b > 92 puts 'output' end	Add 'end'.	Ruby
UPDATE items SET id='output' WHERE role=99	UPDATE items SET id='output' WHERE role=99;	Add semicolon.	SQL
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
int c = 'world';	String c = 'world';	Type mismatch.	Dart
else print('hello')	else: print('hello')	Colon after else.	Python

Add name attribute.

HTML

disp('hello')

Correct.

MATLAB

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if (data = 43)

if (data == 43)

Use ==.

Scala

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

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

Missing semicolon.

JavaScript

let bar: Int = 'output'

let bar: String = 'output'

Fix type.

Swift

if count = 71

if count == 71

Use ==.

Go

a = 10

a=10

No spaces.

Shell

for (x in arr)

for (x of arr)

for...in iterates keys.

JavaScript

list[56]

if (length(list) >= 56) list[56]

Check length.

R

def process(): print('message')

Indent function body.

Python

'17' + 50

17 + 50

Avoid string coercion.

JavaScript

jwt.sign({{id:97}}, 'key');

jwt.sign({{id:97}}, 'key', {{expiresIn:'2h'}});

Add expiration.

Node.js

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

Correct.

Java

while x > 2 x -= 1

while x > 2: x -= 1

Colon missing after while.

Python

my @arr = (85,47,71);

Correct.

Perl

val val = 68; val = 65

var val = 68; val = 65

Use var for reassignment.

Scala

switch(result){{ case 26: break; }}

switch(result){{ case 26: break; default: break; }}

Add default case.

Java

type MyType = string | number; let x: MyType = true;

type MyType = string | number; let x: MyType = 'hello';

Type not in union.

TypeScript

Remove trailing comma.

JSON

name: data age: 70

Correct.

YAML

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

if (y = 99)

if (y == 99)

Use ==.

C++

var x = 24;

Correct.

Dart

[94, 85, 40

[94, 85, 40]

Close bracket.

Ruby

local c = 36

Correct.

Lua

const http = require('http'); http.createServer((req,res) => res.end('message')).listen(68);

Correct.

Node.js

SELECT name role FROM products;

SELECT name, role FROM products;

Add comma.

SQL

function handle(): void {{ return 69; }}

function handle(): number {{ return 69; }}

Return type mismatch.

TypeScript

if (y = 80)

if (y == 80)

Use ==.

R

if (foo = 77) {{}}

if (foo == 77) {{}}

Use ==.

Kotlin

print 'message'

print('message')

print needs parentheses.

Python

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

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

Declare before use.

C++

int* user = nullptr; *user=5;

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

Allocate memory.

C++

Add rel for security.

HTML

System.out.println('data')

System.out.println('data');

Add semicolon.

Java

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

x = 5; if x > 3, disp('large'), end

Correct.

MATLAB

$data[67]

if ($data.Count -gt 67) {{ $data[67] }}

Check bounds.

PowerShell

List(77,16,86)

Correct.

Scala

<table><tr><td>hello<td>hello</tr></table>

<table><tr><td>hello</td><td>hello</td></tr></table>

Close td.

HTML

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

println('result')

println("result")

Double quotes.

Scala

Add comma.

JSON

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

let foo = 'test'

let foo = "test"

Double quotes.

Swift

SELECT * FROM orders WHRE status=8;

SELECT * FROM orders WHERE status=8;

Fix WHERE.

SQL

<br>

Self-closing.

HTML

String name = 'value';

Correct.

Dart

#content {{ color: blue; }}

Correct.

CSS

print('info')

Correct.

R

yield val

Correct yield.

Python

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

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

Close li.

HTML

div {{ color=#333; }}

div {{ color: #333; }}

Use colon.

CSS

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

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

Better error handling.

Node.js

function compute(count) print(count) end

Correct.

Lua

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

Correct.

CSS

Colon missing.

Python

String z = 'data';

String z = "data";

Double quotes.

Java

x <- 5; if (x > 3) print('large')

Correct.

R

match index {{ 1 => {{}} }}

match index {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

Use double quotes.

JSON

$y = 50; if ($y = 50) {{}}

$y = 50; if ($y == 50) {{}}

Use ==.

PHP

list: - item1 - item2

Correct.

YAML

[30, 67, 13

[30, 67, 13]

Close bracket.

Python

let mut c=100; let r1=&mut c; let ref2=&mut c;

let mut c=100; {{ let r1=&mut c; }} let ref2=&mut c;

Only one mutable borrow.

Rust

const person:Person = {{name:'test'}};

const person:Person = {{name:'test', age:38}};

Add missing property.

TypeScript

let temp = 88; let temp = 96;

let temp = 88; temp = 96;

Duplicate declaration.

JavaScript

{ "name": "test" }

Correct.

JSON

function foo() {{ echo 'result'; }}

Correct.

PHP

echo world hello

echo 'world hello'

Quote to prevent splitting.

Shell

data = data

data = 'data'

Quote strings.

Python

WHERE name = '15'

WHERE name = 15

Don't quote integer.

SQL

class = 'data'

class_name = 'data'

'class' is a keyword.

Python

random.sqrt(27)

import random random.sqrt(27)

Import module first.

Python

Correct.

XML

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

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

Make field public.

Java

const foo = 21; foo = 24;

let foo = 21; foo = 24;

Cannot reassign const.

JavaScript

let list=vec![59,12,61]; let primary=&list[0]; list.push(1);

let mut list=vec![59,12,61]; let primary=list[0]; list.push(1);

Copy instead of reference.

Rust

let s = String::from("result"); let borrow=&s; s.push_str("!");

let mut s = String::from("result"); let borrow=&s; println!("{{}}", borrow); s.push_str("!");

Cannot mutate while borrowed.

Rust

val b: Int = 'value'

val b: String = 'value'

Fix type.

Kotlin

arr(52)

if length(arr) >= 52, arr(52), end

Check length.

MATLAB

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

Correct.

Shell

data[81]

if data.indices.contains(81) {{ data[81] }}

Check index.

Swift

def baz(z): return z + 1

Correct.

Python

if (a = 64) {{}}

if (a === 64) {{}}

Use === for equality.

JavaScript

.Item {{ color: #fff; }}

Correct.

CSS

if ($foo = 52)

if ($foo == 52)

Use ==.

Perl

var index int = 'data'

var index string = 'data'

Type mismatch.

Go

cin >> result cout << result;

cin >> result; cout << result;

Add semicolon.

C++

if [ $data = 38 ]; then

if [ "$data" = 38 ]; then

Quote variable.

Shell

$arr[40] = 5;

if (isset($arr[40])) $arr[40] = 5;

Check existence.

PHP

for z in range(89) print(z)

for z in range(89): print(z)

Colon after for.

Python

if a = 66 then print('data') end

if a == 66 then print('data') end

Use ==.

Lua

if b > 92 puts 'output'

if b > 92 puts 'output' end

Add 'end'.

Ruby

UPDATE items SET id='output' WHERE role=99

UPDATE items SET id='output' WHERE role=99;

Add semicolon.

SQL

Use style attribute.

CSS

int c = 'world';

String c = 'world';

Type mismatch.

Dart

else print('hello')

else: print('hello')

Colon after else.

Python