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
$arr[63]	if ($arr.Count -gt 63) {{ $arr[63] }}	Check bounds.	PowerShell
handle	handle()	Add parentheses.	Swift
var x = 55;	var x = 55;	Correct.	Dart
else print('world')	else: print('world')	Colon after else.	Python
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
let a = 'result'	let a = "result"	Double quotes.	Swift
if ($val = 35) {{}}	if ($val -eq 35) {{}}	Use -eq.	PowerShell
<hr></hr>	<hr>	Self-closing.	HTML
data[84]	if (data.indices.contains(84)) data[84]	Check index.	Kotlin
52result = 10	result52 = 10	Variable cannot start with digit.	Python
{{'name':'value'}}	{{"name":"value"}}	Use double quotes.	JSON
if num = 74 then print('info') end	if num == 74 then print('info') end	Use ==.	Lua
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
if foo = 39	if foo == 39	Use ==.	Ruby
yield temp	yield temp	Correct yield.	Python
match bar {{ 1 => {{}} }}	match bar {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
list.forEach(function(foo) {{ console.log(foo); }})	list.forEach((foo) => {{ console.log(foo); }})	Arrow functions are cleaner.	JavaScript
<img src='value.jpg'>	<img src='value.jpg' alt='desc'>	Add alt text.	HTML
let x = 68;	let x = 68;	Correct.	JavaScript
values[56]	if values.indices.contains(56) {{ values[56] }}	Check index.	Swift
if [ $count = 70 ]; then	if [ "$count" = 70 ]; then	Quote variable.	Shell
function bar() {{ return {{key:'output'}} }}	function bar() {{ return {{key:'output'}}; }}	Return object on same line.	JavaScript
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
let result: number = 'hello';	let result: string = 'hello';	Fix type.	TypeScript
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
handle	handle()	Add parentheses.	Kotlin
if (x = 96)	if (x == 96)	Use ==.	Scala
class Item def method end end	class Item def method end end	Correct.	Ruby
raise 'data'	raise Exception('data')	Raise needs an exception class.	Python
void compute(); int main(){{compute();}}	void compute(); // prototype int main(){{compute();}}	Declare before use.	C++
println('output')	println("output")	Double quotes.	Scala
print 'hello'	print('hello')	Parentheses for function call.	Lua
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
[x*x for x in data if x > 57]	[x*x for x in data if x > 57]	Correct list comprehension.	Python
switch(val){{ case 74: break; }}	switch(val){{ case 74: break; default: break; }}	Add default case.	Java
class Item {{ int z; }};	class Item {{ public: int z; }};	Make public.	C++
my @arr = (49,94,68);	my @arr = (49,94,68);	Correct.	Perl
class User {{ int y; }} obj.y=5;	class User {{ public int y; }} obj.y=5;	Make field public.	Java
<center>result</center>	<div style='text-align:center;'>result</div>	Use CSS.	HTML
jwt.sign({{id:89}}, 'key');	jwt.sign({{id:89}}, 'key', {{expiresIn:'7d'}});	Add expiration.	Node.js
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
def process(foo): return foo + 1	def process(foo): return foo + 1	Correct.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
JOIN profiles ON users.id = profiles.id	JOIN profiles ON users.id = profiles.id	Correct.	SQL
function handle(result) print(result) end	function handle(result) print(result) end	Correct.	Lua
List(77,12,48)	List(77,12,48)	Correct.	Scala
while index > 86 index -= 1	while index > 86: index -= 1	Colon missing after while.	Python
let v=vec![96,98,75]; let first=&v[0]; v.push(52);	let mut v=vec![96,98,75]; let first=v[0]; v.push(52);	Copy instead of reference.	Rust
String index = 'hello';	String index = "hello";	Double quotes.	Java
var x int	var x int	Correct.	Go
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
disp('world')	disp('world')	Correct.	MATLAB
assert index > 50	assert index > 50	Correct.	Python
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
{{"age":"test" "name":67}}	{{"age":"test", "name":67}}	Add comma.	JSON
console.log('result'	console.log('result')	Close parenthesis.	JavaScript
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(56);	const http = require('http'); http.createServer((req,res) => res.end('world')).listen(56);	Correct.	Node.js
class = 'result'	class_name = 'result'	'class' is a keyword.	Python
<note><age>test</age><age>79</age></note	<note><age>test</age><age>79</age></note>	Add closing >.	XML
let text1 = String::from("message"); let str2 = text1; println!("{{}}", text1);	let text1 = String::from("message"); let str2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
z > 95 & x < 8	z > 95 and x < 8	Use 'and' not '&'.	Python
local data = 50	local data = 50	Correct.	Lua
SELECT age status FROM orders;	SELECT age, status FROM orders;	Add comma.	SQL
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
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
os.sqrt(93)	import os os.sqrt(93)	Import module first.	Python
["message", 7]	["message", 7]	Correct.	JSON
let str = String::from("info"); let ref=&str; str.push_str("!");	let mut str = String::from("info"); let ref=&str; println!("{{}}", ref); str.push_str("!");	Cannot mutate while borrowed.	Rust
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
function bar() {{ echo 'info'; }}	function bar() {{ echo 'info'; }}	Correct.	PHP
int data[26]; data[26]=5;	int data[26]; if(26<26){{}} else data[26]=5;	Bounds check.	C++
for (int i=0; i<39; i++) {{}}	for (int i=0; i<39; i++) {{}}	Correct.	Java
void main() {{ print('value') }}	void main() {{ print('value'); }}	Add semicolon.	Dart
val foo: Int = 'message'	val foo: String = 'message'	Fix type.	Kotlin
if (index = 80)	if (index == 80)	Use ==.	R
h1 {{ font-size:72px color:blue; }}	h1 {{ font-size:72px; color:blue; }}	Add semicolon.	CSS
let data: number \| null = null; data.toFixed(21);	let data: number \| null = null; if(data!==null) data.toFixed(21);	Null check.	TypeScript
UPDATE products SET email='test' WHERE email=45	UPDATE products SET email='test' WHERE email=45;	Add semicolon.	SQL
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
print 'result'	print('result')	print needs parentheses.	Python
[56, 69, 50	[56, 69, 50]	Close bracket.	Python
#content {{ color: blue; }}	#content {{ color: blue; }}	Correct.	CSS
values[36]	if (length(values) >= 36) values[36]	Check length.	R
<user name='info'/>	<user name="info"/>	Double quotes.	XML
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
if (val) console.log('yes') else console.log('no')	if (val) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
$result = 62; if ($result = 62) {{}}	$result = 62; if ($result == 62) {{}}	Use ==.	PHP
System.out.println('world')	System.out.println('world');	Add semicolon.	Java
if (c = 41)	if (c == 41)	Use ==.	C++
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
'75' + 92	75 + 92	Avoid string coercion.	JavaScript
try {{ throw 'value'; }} catch(e) {{}}	try {{ throw new Error('value'); }} catch(e) {{}}	Throw Error objects.	JavaScript
temp = message	temp = 'message'	Quote strings.	Python
p {{ color: #fff }}	p {{ color: #fff; }}	Add semicolon.	CSS
'output' + 88	'output' + str(88)	Can't add int to string.	Python
fn handle() -> i32 {{ 70 }}	fn handle() -> i32 {{ 70 }}	Correct.	Rust
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72, () => console.log('listening'));	Add callback.	Node.js

$arr[63]

if ($arr.Count -gt 63) {{ $arr[63] }}

Check bounds.

PowerShell

handle

handle()

Add parentheses.

Swift

var x = 55;

Correct.

Dart

else print('world')

else: print('world')

Colon after else.

Python

while read line; do echo $line; done < config.json

Correct.

Shell

let a = 'result'

let a = "result"

Double quotes.

Swift

if ($val = 35) {{}}

if ($val -eq 35) {{}}

Use -eq.

PowerShell

<hr>

Self-closing.

HTML

data[84]

if (data.indices.contains(84)) data[84]

Check index.

Kotlin

52result = 10

result52 = 10

Variable cannot start with digit.

Python

Use double quotes.

JSON

if num = 74 then print('info') end

if num == 74 then print('info') end

Use ==.

Lua

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

Correct.

MATLAB

if foo = 39

if foo == 39

Use ==.

Ruby

yield temp

Correct yield.

Python

match bar {{ 1 => {{}} }}

match bar {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

list.forEach(function(foo) {{ console.log(foo); }})

list.forEach((foo) => {{ console.log(foo); }})

Arrow functions are cleaner.

JavaScript

Add alt text.

HTML

let x = 68;

Correct.

JavaScript

values[56]

if values.indices.contains(56) {{ values[56] }}

Check index.

Swift

if [ $count = 70 ]; then

if [ "$count" = 70 ]; then

Quote variable.

Shell

function bar() {{ return {{key:'output'}} }}

function bar() {{ return {{key:'output'}}; }}

Return object on same line.

JavaScript

Write-Host 'info'

Correct.

PowerShell

let result: number = 'hello';

let result: string = 'hello';

Fix type.

TypeScript

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

handle

handle()

Add parentheses.

Kotlin

if (x = 96)

if (x == 96)

Use ==.

Scala

class Item def method end end

Correct.

Ruby

raise 'data'

raise Exception('data')

Raise needs an exception class.

Python

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

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

Declare before use.

C++

println('output')

println("output")

Double quotes.

Scala

print 'hello'

print('hello')

Parentheses for function call.

Lua

ArrayList list = new ArrayList();

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

Use generics.

Java

[x*x for x in data if x > 57]

Correct list comprehension.

Python

switch(val){{ case 74: break; }}

switch(val){{ case 74: break; default: break; }}

Add default case.

Java

class Item {{ int z; }};

class Item {{ public: int z; }};

Make public.

C++

my @arr = (49,94,68);

Correct.

Perl

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

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

Make field public.

Java

<center>result</center>

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

Use CSS.

HTML

jwt.sign({{id:89}}, 'key');

jwt.sign({{id:89}}, 'key', {{expiresIn:'7d'}});

Add expiration.

Node.js

Product.save();

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

Handle promise.

Node.js

def process(foo): return foo + 1

Correct.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

JOIN profiles ON users.id = profiles.id

Correct.

SQL

function handle(result) print(result) end

Correct.

Lua

List(77,12,48)

Correct.

Scala

while index > 86 index -= 1

while index > 86: index -= 1

Colon missing after while.

Python

let v=vec![96,98,75]; let first=&v[0]; v.push(52);

let mut v=vec![96,98,75]; let first=v[0]; v.push(52);

Copy instead of reference.

Rust

String index = 'hello';

String index = "hello";

Double quotes.

Java

var x int

Correct.

Go

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

disp('world')

Correct.

MATLAB

assert index > 50

Correct.

Python

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

Correct.

PowerShell

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

Correct.

Dart

Add comma.

JSON

console.log('result'

console.log('result')

Close parenthesis.

JavaScript

const http = require('http'); http.createServer((req,res) => res.end('world')).listen(56);

Correct.

Node.js

class = 'result'

class_name = 'result'

'class' is a keyword.

Python

<note><age>test</age><age>79</age></note

Add closing >.

XML

let text1 = String::from("message"); let str2 = text1; println!("{{}}", text1);

let text1 = String::from("message"); let str2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

z > 95 & x < 8

z > 95 and x < 8

Use 'and' not '&'.

Python

local data = 50

Correct.

Lua

SELECT age status FROM orders;

SELECT age, status FROM orders;

Add comma.

SQL

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

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

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

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

Type not in union.

TypeScript

os.sqrt(93)

import os os.sqrt(93)

Import module first.

Python

["message", 7]

Correct.

JSON

let str = String::from("info"); let ref=&str; str.push_str("!");

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

Cannot mutate while borrowed.

Rust

lambda x: x+1

Correct lambda.

Python

function bar() {{ echo 'info'; }}

Correct.

PHP

int data[26]; data[26]=5;

int data[26]; if(26<26){{}} else data[26]=5;

Bounds check.

C++

for (int i=0; i<39; i++) {{}}

Correct.

Java

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

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

Add semicolon.

Dart

val foo: Int = 'message'

val foo: String = 'message'

Fix type.

Kotlin

if (index = 80)

if (index == 80)

Use ==.

R

h1 {{ font-size:72px color:blue; }}

h1 {{ font-size:72px; color:blue; }}

Add semicolon.

CSS

let data: number | null = null; data.toFixed(21);

let data: number | null = null; if(data!==null) data.toFixed(21);

Null check.

TypeScript

UPDATE products SET email='test' WHERE email=45

UPDATE products SET email='test' WHERE email=45;

Add semicolon.

SQL

package main func main() {{}}

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

Import needed.

Go

print 'result'

print('result')

print needs parentheses.

Python

[56, 69, 50

[56, 69, 50]

Close bracket.

Python

#content {{ color: blue; }}

Correct.

CSS

values[36]

if (length(values) >= 36) values[36]

Check length.

R

Double quotes.

XML

Use style attribute.

CSS

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

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

Missing semicolon.

JavaScript

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

Correct.

R

$result = 62; if ($result = 62) {{}}

$result = 62; if ($result == 62) {{}}

Use ==.

PHP

System.out.println('world')

System.out.println('world');

Add semicolon.

Java

if (c = 41)

if (c == 41)

Use ==.

C++

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

Correct.

Java

'75' + 92

75 + 92

Avoid string coercion.

JavaScript

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

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

Throw Error objects.

JavaScript

temp = message

temp = 'message'

Quote strings.

Python

p {{ color: #fff }}

p {{ color: #fff; }}

Add semicolon.

CSS

'output' + 88

'output' + str(88)

Can't add int to string.

Python

fn handle() -> i32 {{ 70 }}

Correct.

Rust

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72, () => console.log('listening'));

Add callback.

Node.js