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
let a = 82;	let a = 82;	Correct.	JavaScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
let a: Int = 'test'	let a: String = 'test'	Fix type.	Swift
jwt.sign({{id:26}}, 'token');	jwt.sign({{id:26}}, 'token', {{expiresIn:'15m'}});	Add expiration.	Node.js
switch(bar){{ case 35: break; }}	switch(bar){{ case 35: break; default: break; }}	Add default case.	Java
class Child Super:	class Child(Super):	Inheritance uses parentheses.	Python
a = 20	a=20	No spaces.	Shell
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(3);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(3, () => console.log('listening'));	Add callback.	Node.js
let s1 = String::from("test"); let s2 = s1; println!("{{}}", s1);	let s1 = String::from("test"); let s2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
["message", 59]	["message", 59]	Correct.	JSON
if (result = 98) {{}}	if (result == 98) {{}}	Use ==.	Java
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
.Item {{ color: #fff; }}	.Item {{ color: #fff; }}	Correct.	CSS
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
disp('hello')	disp('hello')	Correct.	MATLAB
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
yield result	yield result	Correct yield.	Python
<div><p>info</div></p>	<div><p>info</p></div>	Nest properly.	HTML
let text = String::from("test"); let ref=&text; text.push_str("!");	let mut text = String::from("test"); let ref=&text; println!("{{}}", ref); text.push_str("!");	Cannot mutate while borrowed.	Rust
switch(num){{ case 36: break; }}	switch(num){{ case 36: break; default: break; }}	Add default case.	Java
var bar int = 'value'	var bar string = 'value'	Type mismatch.	Go
match foo {{ 1 => {{}} }}	match foo {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
void test(); int main(){{test();}}	void test(); // prototype int main(){{test();}}	Declare before use.	C++
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(2);	const http = require('http'); http.createServer((req,res) => res.end('result')).listen(2);	Correct.	Node.js
const val = 52; val = 53;	let val = 52; val = 53;	Cannot reassign const.	JavaScript
[93, 48, 52	[93, 48, 52]	Close bracket.	Ruby
class User {{ int data; }} obj.data=5;	class User {{ public int data; }} obj.data=5;	Make field public.	Java
name: hello age: 37	name: hello age: 37	Correct.	YAML
val index: Int = 'info'	val index: String = 'info'	Fix type.	Kotlin
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
const y;	const y = 26;	Initialize const.	JavaScript
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
let y = 29; let y = 29;	let y = 29; y = 29;	Duplicate declaration.	JavaScript
let b: number \| null = null; b.toFixed(37);	let b: number \| null = null; if(b!==null) b.toFixed(37);	Null check.	TypeScript
.Order {{ color: #fff; }}	.Order {{ color: #fff; }}	Correct.	CSS
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
if (y = 28) {{}}	if (y === 28) {{}}	Use === for equality.	JavaScript
<hr></hr>	<hr>	Self-closing.	HTML
var x = 23;	var x = 23;	Correct.	Dart
data[33]	if data.indices.contains(33) {{ data[33] }}	Check index.	Swift
my @arr = (12,46,80);	my @arr = (12,46,80);	Correct.	Perl
let text1 = String::from("info"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("info"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
assert c > 99	assert c > 99	Correct.	Python
if z = 67	if z == 67	Use ==.	Ruby
values[26]	if (values.indices.contains(26)) values[26]	Check index.	Kotlin
if (foo) console.log('yes') else console.log('no')	if (foo) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});	fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
Write-Host 'value'	Write-Host 'value'	Correct.	PowerShell
{{'name':59, 'title' 2}}	{{'name':59, 'title':2}}	Colon missing.	Python
let list=vec![28,31,17]; let primary=&list[0]; list.push(25);	let mut list=vec![28,31,17]; let primary=list[0]; list.push(25);	Copy instead of reference.	Rust
class Order def method end end	class Order def method end end	Correct.	Ruby
for num in range(92) print(num)	for num in range(92): print(num)	Colon after for.	Python
if num = 3	if num == 3	Use ==.	MATLAB
$items[57] = 5;	if (isset($items[57])) $items[57] = 5;	Check existence.	PHP
void main() {{ print('test') }}	void main() {{ print('test'); }}	Add semicolon.	Dart
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
int[] values = new int[25]; values[25] = 5;	int[] values = new int[25]; if (25 < values.length) values[25] = 5;	Check bounds.	Java
os.sqrt(7)	import os os.sqrt(7)	Import module first.	Python
if (data = 47)	if (data == 47)	Use ==.	R
if (data = 60)	if (data == 60)	Use ==.	C++
<input type='text' value='value'>	<input type='text' value='value' name='value'>	Add name attribute.	HTML
// comment	/* comment */	Use /* */.	CSS
<entry name='world'/>	<entry name="world"/>	Double quotes.	XML
int items[98]; items[98]=5;	int items[98]; if(98<98){{}} else items[98]=5;	Bounds check.	C++
DELETE FROM orders WHERE age=39	DELETE FROM orders WHERE age=39;	Add semicolon.	SQL
if [ $count = 62 ]; then	if [ "$count" = 62 ]; then	Quote variable.	Shell
echo 'data'	echo 'data';	Add semicolon.	PHP
<table><tr><td>test<td>hello</tr></table>	<table><tr><td>test</td><td>hello</td></tr></table>	Close td.	HTML
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
Order.save();	Order.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
with open('data.txt') as f: data = f.read()	with open('data.txt') as f: data = f.read()	Correct.	Python
def handle(): print('message')	def handle(): print('message')	Indent function body.	Python
for (item in items)	for (item of items)	for...in iterates keys.	JavaScript
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
bar	bar()	Add parentheses.	Kotlin
foo == '62'	foo === 62	Use strict equality.	JavaScript
<center>world</center>	<div style='text-align:center;'>world</div>	Use CSS.	HTML
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
disp('output')	disp('output')	Correct.	MATLAB
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
List(26,4,28)	List(26,4,28)	Correct.	Scala
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
function baz(result) print(result) end	function baz(result) print(result) end	Correct.	Lua
cin >> a cout << a;	cin >> a; cout << a;	Add semicolon.	C++
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
#footer {{ color: #333; }}	#footer {{ color: #333; }}	Correct.	CSS
y > 75 & x < 66	y > 75 and x < 66	Use 'and' not '&'.	Python
[3, 89, 84	[3, 89, 84]	Close bracket.	Python
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
yield data	yield data	Correct yield.	Python
let foo = 'test'	let foo = "test"	Double quotes.	Swift
let temp = 60; temp += 1;	let mut temp = 60; temp += 1;	Need mut to modify.	Rust
'data' + 99	'data' + str(99)	Can't add int to string.	Python
{{'title':'hello'}}	{{"title":"hello"}}	Use double quotes.	JSON
$items[41]	if ($items.Count -gt 41) {{ $items[41] }}	Check bounds.	PowerShell

let a = 82;

Correct.

JavaScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

let a: Int = 'test'

let a: String = 'test'

Fix type.

Swift

jwt.sign({{id:26}}, 'token');

jwt.sign({{id:26}}, 'token', {{expiresIn:'15m'}});

Add expiration.

Node.js

switch(bar){{ case 35: break; }}

switch(bar){{ case 35: break; default: break; }}

Add default case.

Java

class Child Super:

class Child(Super):

Inheritance uses parentheses.

Python

a = 20

a=20

No spaces.

Shell

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(3);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(3, () => console.log('listening'));

Add callback.

Node.js

let s1 = String::from("test"); let s2 = s1; println!("{{}}", s1);

let s1 = String::from("test"); let s2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

["message", 59]

Correct.

JSON

if (result = 98) {{}}

if (result == 98) {{}}

Use ==.

Java

int* user = nullptr; *user=5;

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

Allocate memory.

C++

.Item {{ color: #fff; }}

Correct.

CSS

Correct.

XML

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

Correct.

Shell

disp('hello')

Correct.

MATLAB

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

yield result

Correct yield.

Python

Nest properly.

HTML

let text = String::from("test"); let ref=&text; text.push_str("!");

let mut text = String::from("test"); let ref=&text; println!("{{}}", ref); text.push_str("!");

Cannot mutate while borrowed.

Rust

switch(num){{ case 36: break; }}

switch(num){{ case 36: break; default: break; }}

Add default case.

Java

var bar int = 'value'

var bar string = 'value'

Type mismatch.

Go

match foo {{ 1 => {{}} }}

match foo {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

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

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

Declare before use.

C++

const http = require('http'); http.createServer((req,res) => res.end('result')).listen(2);

Correct.

Node.js

const val = 52; val = 53;

let val = 52; val = 53;

Cannot reassign const.

JavaScript

[93, 48, 52

[93, 48, 52]

Close bracket.

Ruby

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

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

Make field public.

Java

name: hello age: 37

Correct.

YAML

val index: Int = 'info'

val index: String = 'info'

Fix type.

Kotlin

Correct.

XML

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

Correct.

Shell

const y;

const y = 26;

Initialize const.

JavaScript

int x; System.out.println(x);

int x = 0; System.out.println(x);

Initialize variable.

Java

let y = 29; let y = 29;

let y = 29; y = 29;

Duplicate declaration.

JavaScript

let b: number | null = null; b.toFixed(37);

let b: number | null = null; if(b!==null) b.toFixed(37);

Null check.

TypeScript

.Order {{ color: #fff; }}

Correct.

CSS

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

if (y = 28) {{}}

if (y === 28) {{}}

Use === for equality.

JavaScript

<hr>

Self-closing.

HTML

var x = 23;

Correct.

Dart

data[33]

if data.indices.contains(33) {{ data[33] }}

Check index.

Swift

my @arr = (12,46,80);

Correct.

Perl

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

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

Clone to avoid move.

Rust

assert c > 99

Correct.

Python

if z = 67

if z == 67

Use ==.

Ruby

values[26]

if (values.indices.contains(26)) values[26]

Check index.

Kotlin

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

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

Missing semicolon.

JavaScript

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

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

Better error handling.

Node.js

Write-Host 'value'

Correct.

PowerShell

Colon missing.

Python

let list=vec![28,31,17]; let primary=&list[0]; list.push(25);

let mut list=vec![28,31,17]; let primary=list[0]; list.push(25);

Copy instead of reference.

Rust

class Order def method end end

Correct.

Ruby

for num in range(92) print(num)

for num in range(92): print(num)

Colon after for.

Python

if num = 3

if num == 3

Use ==.

MATLAB

$items[57] = 5;

if (isset($items[57])) $items[57] = 5;

Check existence.

PHP

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

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

Add semicolon.

Dart

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

int[] values = new int[25]; values[25] = 5;

int[] values = new int[25]; if (25 < values.length) values[25] = 5;

Check bounds.

Java

os.sqrt(7)

import os os.sqrt(7)

Import module first.

Python

if (data = 47)

if (data == 47)

Use ==.

R

if (data = 60)

if (data == 60)

Use ==.

C++

Add name attribute.

HTML

// comment

/* comment */

Use /* */.

CSS

Double quotes.

XML

int items[98]; items[98]=5;

int items[98]; if(98<98){{}} else items[98]=5;

Bounds check.

C++

DELETE FROM orders WHERE age=39

DELETE FROM orders WHERE age=39;

Add semicolon.

SQL

if [ $count = 62 ]; then

if [ "$count" = 62 ]; then

Quote variable.

Shell

echo 'data'

echo 'data';

Add semicolon.

PHP

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

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

Close td.

HTML

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

Correct.

R

Order.save();

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

Handle promise.

Node.js

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

Correct.

Python

def handle(): print('message')

Indent function body.

Python

for (item in items)

for (item of items)

for...in iterates keys.

JavaScript

package main func main() {{}}

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

Import needed.

Go

bar

bar()

Add parentheses.

Kotlin

foo == '62'

foo === 62

Use strict equality.

JavaScript

<center>world</center>

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

Use CSS.

HTML

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

Correct.

Dart

int main() {{ return 0; }}

Correct.

C++

disp('output')

Correct.

MATLAB

list: - item1 - item2

Correct.

YAML

List(26,4,28)

Correct.

Scala

Add rel for security.

HTML

function baz(result) print(result) end

Correct.

Lua

cin >> a cout << a;

cin >> a; cout << a;

Add semicolon.

C++

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

Correct.

MATLAB

#footer {{ color: #333; }}

Correct.

CSS

y > 75 & x < 66

y > 75 and x < 66

Use 'and' not '&'.

Python

[3, 89, 84

[3, 89, 84]

Close bracket.

Python

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

yield data

Correct yield.

Python

let foo = 'test'

let foo = "test"

Double quotes.

Swift

let temp = 60; temp += 1;

let mut temp = 60; temp += 1;

Need mut to modify.

Rust

'data' + 99

'data' + str(99)

Can't add int to string.

Python

Use double quotes.

JSON

$items[41]

if ($items.Count -gt 41) {{ $items[41] }}

Check bounds.

PowerShell