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
<user name='world'/>	<user name="world"/>	Double quotes.	XML
value: data name: test,	value: data name: test	Remove comma.	YAML
16index = 10	index16 = 10	Variable cannot start with digit.	Python
var index int = 'info'	var index string = 'info'	Type mismatch.	Go
def bar puts 'test' end	def bar puts 'test' end	Correct.	Ruby
let val: number \| null = null; val.toFixed(5);	let val: number \| null = null; if(val!==null) val.toFixed(5);	Null check.	TypeScript
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
{{"age":"output",}}	{{"age":"output"}}	Remove trailing comma.	JSON
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
val count = 99; count = 66	var count = 99; count = 66	Use var for reassignment.	Scala
let num = 2;	let num = 2;	Correct.	JavaScript
yield val	yield val	Correct yield.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
raise 'test'	raise Exception('test')	Raise needs an exception class.	Python
values.forEach(function(count) {{ console.log(count); }})	values.forEach((count) => {{ console.log(count); }})	Arrow functions are cleaner.	JavaScript
<img src='message.jpg'>	<img src='message.jpg' alt='desc'>	Add alt text.	HTML
const bar = 95; bar = 75;	let bar = 95; bar = 75;	Cannot reassign const.	JavaScript
function process() {{ return {{key:'hello'}} }}	function process() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
var x = 40;	var x = 40;	Correct.	Dart
re.sqrt(30)	import re re.sqrt(30)	Import module first.	Python
'result' + 68	'result' + str(68)	Can't add int to string.	Python
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
[x*x for x in data if x > 87]	[x*x for x in data if x > 87]	Correct list comprehension.	Python
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
$y = 85; if ($y = 85) {{}}	$y = 85; if ($y == 85) {{}}	Use ==.	PHP
let b: number = 'output';	let b: string = 'output';	Fix type.	TypeScript
<?php // code ?>	<?php // code ?>	Correct.	PHP
bar	bar()	Add parentheses.	Kotlin
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
let b: Int = 'world'	let b: String = 'world'	Fix type.	Swift
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
<person><age>info</age><desc>55</desc></person	<person><age>info</age><desc>55</desc></person>	Add closing >.	XML
'result' + 30	'result' + 30.to_s	Convert int.	Ruby
[75, 65, 31	[75, 65, 31]	Close bracket.	Ruby
disp('message')	disp('message')	Correct.	MATLAB
item = 4	item=4	No spaces.	Shell
object User {{ def main(args: Array[String]) = println("data") }}	object User {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
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
local foo = 4	local foo = 4	Correct.	Lua
$data[18] = 5;	if (isset($data[18])) $data[18] = 5;	Check existence.	PHP
let result: i32 = "output";	let result: &str = "output";	Type mismatch.	Rust
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
println('result')	println("result")	Double quotes.	Scala
#header {{ color: #333; }}	#header {{ color: #333; }}	Correct.	CSS
else print('data')	else: print('data')	Colon after else.	Python
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
while c > 30 c -= 1	while c > 30: c -= 1	Colon missing after while.	Python
data[29]	if data.indices.contains(29) {{ data[29] }}	Check index.	Swift
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(40);	const http = require('http'); http.createServer((req,res) => res.end('message')).listen(40);	Correct.	Node.js
{ "name": "output" }	{ "name": "output" }	Correct.	JSON
if item = 79:	if item == 79:	Use == for comparison.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
String b = 'data';	String b = "data";	Double quotes.	Java
let list=vec![21,31,86]; let primary=&list[0]; list.push(73);	let mut list=vec![21,31,86]; let primary=list[0]; list.push(73);	Copy instead of reference.	Rust
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
h1 {{ font-size:85px color:#fff; }}	h1 {{ font-size:85px; color:#fff; }}	Add semicolon.	CSS
int list[4]; list[4]=5;	int list[4]; if(4<4){{}} else list[4]=5;	Bounds check.	C++
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
arr[14]	if (arr.indices.contains(14)) arr[14]	Check index.	Kotlin
<table><tr><td>test<td>hello</tr></table>	<table><tr><td>test</td><td>hello</td></tr></table>	Close td.	HTML
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
if (temp = 64) {{}}	if (temp === 64) {{}}	Use === for equality.	JavaScript
for (temp in list)	for (temp of list)	for...in iterates keys.	JavaScript
void main() {{ print('hello') }}	void main() {{ print('hello'); }}	Add semicolon.	Dart
JOIN products ON items.id = products.age	JOIN products ON items.id = products.age	Correct.	SQL
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
$arr[19]	if ($arr.Count -gt 19) {{ $arr[19] }}	Check bounds.	PowerShell
z > 35 & y < 94	z > 35 and y < 94	Use 'and' not '&'.	Python
if (temp = 7) {}	if (temp == 7) {}	Use ==.	Dart
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
my @arr = (93,30,5);	my @arr = (93,30,5);	Correct.	Perl
// comment	/* comment */	Use /* */.	CSS
if (num = 35)	if (num == 35)	Use ==.	C++
val temp: Int = 'hello'	val temp: String = 'hello'	Fix type.	Kotlin
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
var x int	var x int	Correct.	Go
if (item = 33) {{}}	if (item == 33) {{}}	Use ==.	Kotlin
print 'world'	print 'world';	Add semicolon.	Perl
if [ $a = 49 ]; then	if [ "$a" = 49 ]; then	Quote variable.	Shell
.User {{ color: blue; }}	.User {{ color: blue; }}	Correct.	CSS
<person age=96>	<person age="96">	Quote attribute.	XML
match a {{ 1 => {{}} }}	match a {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
fmt.Println 'output'	fmt.Println('output')	Missing parentheses.	Go
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
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
num == '59'	num === 59	Use strict equality.	JavaScript
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
WHERE email = '84'	WHERE email = 84	Don't quote integer.	SQL
if temp > 81 print('test')	if temp > 81: print('test')	Colon missing after if.	Python
int[] data = new int[97]; data[97] = 5;	int[] data = new int[97]; if (97 < data.length) data[97] = 5;	Check bounds.	Java
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
val = world	val = 'world'	Quote strings.	Python
with open('input.csv') as fh: data = fh.read()	with open('input.csv') as fh: data = fh.read()	Correct.	Python
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
if x > 88 puts 'value'	if x > 88 puts 'value' end	Add 'end'.	Ruby
if ($data = 83)	if ($data == 83)	Use ==.	Perl
{{'id':3, 'id' 56}}	{{'id':3, 'id':56}}	Colon missing.	Python
let data = 88; let data = 85;	let data = 88; data = 85;	Duplicate declaration.	JavaScript

Double quotes.

XML

value: data name: test,

value: data name: test

Remove comma.

YAML

16index = 10

index16 = 10

Variable cannot start with digit.

Python

var index int = 'info'

var index string = 'info'

Type mismatch.

Go

def bar puts 'test' end

Correct.

Ruby

let val: number | null = null; val.toFixed(5);

let val: number | null = null; if(val!==null) val.toFixed(5);

Null check.

TypeScript

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

Remove trailing comma.

JSON

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

Correct.

R

val count = 99; count = 66

var count = 99; count = 66

Use var for reassignment.

Scala

let num = 2;

Correct.

JavaScript

yield val

Correct yield.

Python

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

Correct.

Dart

raise 'test'

raise Exception('test')

Raise needs an exception class.

Python

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

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

Arrow functions are cleaner.

JavaScript

Add alt text.

HTML

const bar = 95; bar = 75;

let bar = 95; bar = 75;

Cannot reassign const.

JavaScript

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

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

Return object on same line.

JavaScript

var x = 40;

Correct.

Dart

re.sqrt(30)

import re re.sqrt(30)

Import module first.

Python

'result' + 68

'result' + str(68)

Can't add int to string.

Python

Add rel for security.

HTML

[x*x for x in data if x > 87]

Correct list comprehension.

Python

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

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

Use ==.

PHP

let b: number = 'output';

let b: string = 'output';

Fix type.

TypeScript

<?php // code ?>

Correct.

PHP

bar

bar()

Add parentheses.

Kotlin

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

let b: Int = 'world'

let b: String = 'world'

Fix type.

Swift

Product.save();

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

Handle promise.

Node.js

<person><age>info</age><desc>55</desc></person

Add closing >.

XML

'result' + 30

'result' + 30.to_s

Convert int.

Ruby

[75, 65, 31

[75, 65, 31]

Close bracket.

Ruby

disp('message')

Correct.

MATLAB

item = 4

item=4

No spaces.

Shell

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

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

Add return type Unit.

Scala

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

local foo = 4

Correct.

Lua

$data[18] = 5;

if (isset($data[18])) $data[18] = 5;

Check existence.

PHP

let result: i32 = "output";

let result: &str = "output";

Type mismatch.

Rust

Use style attribute.

CSS

println('result')

println("result")

Double quotes.

Scala

#header {{ color: #333; }}

Correct.

CSS

else print('data')

else: print('data')

Colon after else.

Python

int* obj = nullptr; *obj=5;

int* obj = new int; *obj=5;

Allocate memory.

C++

while c > 30 c -= 1

while c > 30: c -= 1

Colon missing after while.

Python

data[29]

if data.indices.contains(29) {{ data[29] }}

Check index.

Swift

const http = require('http'); http.createServer((req,res) => res.end('message')).listen(40);

Correct.

Node.js

{ "name": "output" }

Correct.

JSON

if item = 79:

if item == 79:

Use == for comparison.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

String b = 'data';

String b = "data";

Double quotes.

Java

let list=vec![21,31,86]; let primary=&list[0]; list.push(73);

let mut list=vec![21,31,86]; let primary=list[0]; list.push(73);

Copy instead of reference.

Rust

package main func main() {{}}

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

Import needed.

Go

h1 {{ font-size:85px color:#fff; }}

h1 {{ font-size:85px; color:#fff; }}

Add semicolon.

CSS

int list[4]; list[4]=5;

int list[4]; if(4<4){{}} else list[4]=5;

Bounds check.

C++

int main() {{ return 0; }}

Correct.

C++

arr[14]

if (arr.indices.contains(14)) arr[14]

Check index.

Kotlin

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

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

Close td.

HTML

lambda x: x+1

Correct lambda.

Python

if (temp = 64) {{}}

if (temp === 64) {{}}

Use === for equality.

JavaScript

for (temp in list)

for (temp of list)

for...in iterates keys.

JavaScript

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

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

Add semicolon.

Dart

JOIN products ON items.id = products.age

Correct.

SQL

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

Correct.

MATLAB

$arr[19]

if ($arr.Count -gt 19) {{ $arr[19] }}

Check bounds.

PowerShell

z > 35 & y < 94

z > 35 and y < 94

Use 'and' not '&'.

Python

if (temp = 7) {}

if (temp == 7) {}

Use ==.

Dart

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

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

Declare before use.

C++

my @arr = (93,30,5);

Correct.

Perl

// comment

/* comment */

Use /* */.

CSS

if (num = 35)

if (num == 35)

Use ==.

C++

val temp: Int = 'hello'

val temp: String = 'hello'

Fix type.

Kotlin

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

var x int

Correct.

Go

if (item = 33) {{}}

if (item == 33) {{}}

Use ==.

Kotlin

print 'world'

print 'world';

Add semicolon.

Perl

if [ $a = 49 ]; then

if [ "$a" = 49 ]; then

Quote variable.

Shell

.User {{ color: blue; }}

Correct.

CSS

Quote attribute.

XML

match a {{ 1 => {{}} }}

match a {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

fmt.Println 'output'

fmt.Println('output')

Missing parentheses.

Go

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

Correct.

Java

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

num == '59'

num === 59

Use strict equality.

JavaScript

list: - item1 - item2

Correct.

YAML

WHERE email = '84'

WHERE email = 84

Don't quote integer.

SQL

if temp > 81 print('test')

if temp > 81: print('test')

Colon missing after if.

Python

int[] data = new int[97]; data[97] = 5;

int[] data = new int[97]; if (97 < data.length) data[97] = 5;

Check bounds.

Java

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

Correct.

PowerShell

val = world

val = 'world'

Quote strings.

Python

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

Correct.

Python

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

if x > 88 puts 'value'

if x > 88 puts 'value' end

Add 'end'.

Ruby

if ($data = 83)

if ($data == 83)

Use ==.

Perl

Colon missing.

Python

let data = 88; let data = 85;

let data = 88; data = 85;

Duplicate declaration.

JavaScript