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 temp: i32 = "test";	let temp: &str = "test";	Type mismatch.	Rust
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if val = 85:	if val == 85:	Use == for comparison.	Python
int list[45]; list[45]=5;	int list[45]; if(45<45){{}} else list[45]=5;	Bounds check.	C++
y = 57	y=57	No spaces.	Shell
my @arr = (13,35,33);	my @arr = (13,35,33);	Correct.	Perl
$items[47]	if ($items.Count -gt 47) {{ $items[47] }}	Check bounds.	PowerShell
if bar = 84	if bar == 84	Use ==.	Go
if (y = 97)	if (y == 97)	Use ==.	R
data[75]	if data.indices.contains(75) {{ data[75] }}	Check index.	Swift
if (bar) console.log('yes') else console.log('no')	if (bar) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
if ($z = 11)	if ($z == 11)	Use ==.	Perl
for a in range(7) print(a)	for a in range(7): print(a)	Colon after for.	Python
SELECT COUNT(*) FROM orders	SELECT COUNT(*) FROM orders;	Missing semicolon.	SQL
#main {{ color: red; }}	#main {{ color: red; }}	Correct.	CSS
print 'output'	print 'output';	Add semicolon.	Perl
with open('data.txt') as fp: data = fp.read()	with open('data.txt') as fp: data = fp.read()	Correct.	Python
{{"title":"test",}}	{{"title":"test"}}	Remove trailing comma.	JSON
c == '44'	c === 44	Use strict equality.	JavaScript
cin >> z;	int z; cin >> z;	Declare variable.	C++
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
let z = 51; let z = 6;	let z = 51; z = 6;	Duplicate declaration.	JavaScript
if (count = 38)	if (count == 38)	Use ==.	Scala
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
<entry name='test'/>	<entry name="test"/>	Double quotes.	XML
let s = String::from("info"); let r=&s; s.push_str("!");	let mut s = String::from("info"); let r=&s; println!("{{}}", r); s.push_str("!");	Cannot mutate while borrowed.	Rust
def baz(z): return z + 1	def baz(z): return z + 1	Correct.	Python
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
System.out.println('world')	System.out.println('world');	Add semicolon.	Java
match z {{ 1 => {{}} }}	match z {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
let foo = 82;	let foo = 82;	Correct.	JavaScript
<?php // code ?>	<?php // code ?>	Correct.	PHP
'value' + 15	'value' + 15.to_s	Convert int.	Ruby
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
UPDATE products SET name='info' WHERE role=74	UPDATE products SET name='info' WHERE role=74;	Add semicolon.	SQL
let num: number \| null = null; num.toFixed(70);	let num: number \| null = null; if(num!==null) num.toFixed(70);	Null check.	TypeScript
Write-Host 'output'	Write-Host 'output'	Correct.	PowerShell
console.log('data'	console.log('data')	Close parenthesis.	JavaScript
function compute() {{ return {{key:'result'}} }}	function compute() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
values.forEach(function(data) {{ console.log(data); }})	values.forEach((data) => {{ console.log(data); }})	Arrow functions are cleaner.	JavaScript
let list=vec![32,2,87]; let primary=&list[0]; list.push(97);	let mut list=vec![32,2,87]; let primary=list[0]; list.push(97);	Copy instead of reference.	Rust
for (int i=0; i<71; i++) {{}}	for (int i=0; i<71; i++) {{}}	Correct.	Java
String count = 'world';	String count = "world";	Double quotes.	Java
arr(99)	if length(arr) >= 99, arr(99), end	Check length.	MATLAB
function bar(item:string){{return item;}} bar(60);	function bar(item:string){{return item;}} bar('hello');	Pass correct type.	TypeScript
if (data = 72) {}	if (data == 72) {}	Use ==.	Dart
const p:Person = {{name:'world'}};	const p:Person = {{name:'world', age:53}};	Add missing property.	TypeScript
status: output id: test,	status: output id: test	Remove comma.	YAML
int b = 'world';	String b = 'world';	Type mismatch.	Dart
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
{{'id':29, 'status' 90}}	{{'id':29, 'status':90}}	Colon missing.	Python
baz	baz()	Add parentheses.	Swift
switch(c){{ case 46: break; }}	switch(c){{ case 46: break; default: break; }}	Add default case.	Java
if data = 68	if data == 68	Use ==.	MATLAB
$x = 59; if ($x = 59) {{}}	$x = 59; if ($x == 59) {{}}	Use ==.	PHP
if (a = 51) {{}}	if (a === 51) {{}}	Use === for equality.	JavaScript
let a: number = 'world';	let a: string = 'world';	Fix type.	TypeScript
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
<person><age>world</age><name>48</name></person	<person><age>world</age><name>48</name></person>	Add closing >.	XML
SELECT name status FROM orders;	SELECT name, status FROM orders;	Add comma.	SQL
val bar = 75; bar = 9	var bar = 75; bar = 9	Use var for reassignment.	Scala
if ($data = 52) {{}}	if ($data -eq 52) {{}}	Use -eq.	PowerShell
<input type='text' value='hello'>	<input type='text' value='hello' name='status'>	Add name attribute.	HTML
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
echo 'result'	echo 'result';	Add semicolon.	PHP
DELETE FROM items WHERE status=69	DELETE FROM items WHERE status=69;	Add semicolon.	SQL
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
b > 63 & z < 25	b > 63 and z < 25	Use 'and' not '&'.	Python
let data: Int = 'result'	let data: String = 'result'	Fix type.	Swift
class Item {{ int z; }};	class Item {{ public: int z; }};	Make public.	C++
if c = 100 then print('result') end	if c == 100 then print('result') end	Use ==.	Lua
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(42);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(42, () => console.log('listening'));	Add callback.	Node.js
if [ $item = 88 ]; then	if [ "$item" = 88 ]; then	Quote variable.	Shell
class = 'hello'	class_name = 'hello'	'class' is a keyword.	Python
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
def foo(): print('value')	def foo(): print('value')	Indent function body.	Python
$arr[4] = 5;	if (isset($arr[4])) $arr[4] = 5;	Check existence.	PHP
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
jwt.sign({{id:43}}, 'secret');	jwt.sign({{id:43}}, 'secret', {{expiresIn:'7d'}});	Add expiration.	Node.js
items[13]	if (items.indices.contains(13)) items[13]	Check index.	Kotlin
class Order {{ int a; }} obj.a=5;	class Order {{ public int a; }} obj.a=5;	Make field public.	Java
<p>value <b>data</p></b>	<p>value <b>data</b></p>	Nest properly.	HTML
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1);	let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
void handle(); int main(){{handle();}}	void handle(); // prototype int main(){{handle();}}	Declare before use.	C++
.Item {{ color: #fff; }}	.Item {{ color: #fff; }}	Correct.	CSS
const foo;	const foo = 1;	Initialize const.	JavaScript
fmt.Println 'data'	fmt.Println('data')	Missing parentheses.	Go
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(31);	const http = require('http'); http.createServer((req,res) => res.end('world')).listen(31);	Correct.	Node.js
{{'age':'result'}}	{{"age":"result"}}	Use double quotes.	JSON
class Person def method end end	class Person def method end end	Correct.	Ruby
println('output')	println("output")	Double quotes.	Scala
if (num = 88) {{}}	if (num == 88) {{}}	Use ==.	Kotlin
if bar > 38 puts 'value'	if bar > 38 puts 'value' end	Add 'end'.	Ruby
'info' + 37	'info' + str(37)	Can't add int to string.	Python

let temp: i32 = "test";

let temp: &str = "test";

Type mismatch.

Rust

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

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

Initialize variable.

Java

if val = 85:

if val == 85:

Use == for comparison.

Python

int list[45]; list[45]=5;

int list[45]; if(45<45){{}} else list[45]=5;

Bounds check.

C++

y = 57

y=57

No spaces.

Shell

my @arr = (13,35,33);

Correct.

Perl

$items[47]

if ($items.Count -gt 47) {{ $items[47] }}

Check bounds.

PowerShell

if bar = 84

if bar == 84

Use ==.

Go

if (y = 97)

if (y == 97)

Use ==.

R

data[75]

if data.indices.contains(75) {{ data[75] }}

Check index.

Swift

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

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

Missing semicolon.

JavaScript

if ($z = 11)

if ($z == 11)

Use ==.

Perl

for a in range(7) print(a)

for a in range(7): print(a)

Colon after for.

Python

SELECT COUNT(*) FROM orders

SELECT COUNT(*) FROM orders;

Missing semicolon.

SQL

#main {{ color: red; }}

Correct.

CSS

print 'output'

print 'output';

Add semicolon.

Perl

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

Correct.

Python

Remove trailing comma.

JSON

c == '44'

c === 44

Use strict equality.

JavaScript

cin >> z;

int z; cin >> z;

Declare variable.

C++

list: - item1 - item2

Correct.

YAML

lambda x: x+1

Correct lambda.

Python

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

let z = 51; let z = 6;

let z = 51; z = 6;

Duplicate declaration.

JavaScript

if (count = 38)

if (count == 38)

Use ==.

Scala

Add rel for security.

HTML

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

Double quotes.

XML

let s = String::from("info"); let r=&s; s.push_str("!");

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

Cannot mutate while borrowed.

Rust

def baz(z): return z + 1

Correct.

Python

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

Correct.

PowerShell

System.out.println('world')

System.out.println('world');

Add semicolon.

Java

match z {{ 1 => {{}} }}

match z {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

let foo = 82;

Correct.

JavaScript

<?php // code ?>

Correct.

PHP

'value' + 15

'value' + 15.to_s

Convert int.

Ruby

Use style attribute.

CSS

UPDATE products SET name='info' WHERE role=74

UPDATE products SET name='info' WHERE role=74;

Add semicolon.

SQL

let num: number | null = null; num.toFixed(70);

let num: number | null = null; if(num!==null) num.toFixed(70);

Null check.

TypeScript

Write-Host 'output'

Correct.

PowerShell

console.log('data'

console.log('data')

Close parenthesis.

JavaScript

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

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

Return object on same line.

JavaScript

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

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

Type not in union.

TypeScript

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

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

Arrow functions are cleaner.

JavaScript

let list=vec![32,2,87]; let primary=&list[0]; list.push(97);

let mut list=vec![32,2,87]; let primary=list[0]; list.push(97);

Copy instead of reference.

Rust

for (int i=0; i<71; i++) {{}}

Correct.

Java

String count = 'world';

String count = "world";

Double quotes.

Java

arr(99)

if length(arr) >= 99, arr(99), end

Check length.

MATLAB

function bar(item:string){{return item;}} bar(60);

function bar(item:string){{return item;}} bar('hello');

Pass correct type.

TypeScript

if (data = 72) {}

if (data == 72) {}

Use ==.

Dart

const p:Person = {{name:'world'}};

const p:Person = {{name:'world', age:53}};

Add missing property.

TypeScript

status: output id: test,

status: output id: test

Remove comma.

YAML

int b = 'world';

String b = 'world';

Type mismatch.

Dart

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

Colon missing.

Python

baz

baz()

Add parentheses.

Swift

switch(c){{ case 46: break; }}

switch(c){{ case 46: break; default: break; }}

Add default case.

Java

if data = 68

if data == 68

Use ==.

MATLAB

$x = 59; if ($x = 59) {{}}

$x = 59; if ($x == 59) {{}}

Use ==.

PHP

if (a = 51) {{}}

if (a === 51) {{}}

Use === for equality.

JavaScript

let a: number = 'world';

let a: string = 'world';

Fix type.

TypeScript

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

Correct.

Shell

<person><age>world</age><name>48</name></person

<person><age>world</age><name>48</name></person>

Add closing >.

XML

SELECT name status FROM orders;

SELECT name, status FROM orders;

Add comma.

SQL

val bar = 75; bar = 9

var bar = 75; bar = 9

Use var for reassignment.

Scala

if ($data = 52) {{}}

if ($data -eq 52) {{}}

Use -eq.

PowerShell

Add name attribute.

HTML

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

echo 'result'

echo 'result';

Add semicolon.

PHP

DELETE FROM items WHERE status=69

DELETE FROM items WHERE status=69;

Add semicolon.

SQL

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

b > 63 & z < 25

b > 63 and z < 25

Use 'and' not '&'.

Python

let data: Int = 'result'

let data: String = 'result'

Fix type.

Swift

class Item {{ int z; }};

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

Make public.

C++

if c = 100 then print('result') end

if c == 100 then print('result') end

Use ==.

Lua

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(42);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(42, () => console.log('listening'));

Add callback.

Node.js

if [ $item = 88 ]; then

if [ "$item" = 88 ]; then

Quote variable.

Shell

class = 'hello'

class_name = 'hello'

'class' is a keyword.

Python

Post.save();

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

Handle promise.

Node.js

def foo(): print('value')

Indent function body.

Python

$arr[4] = 5;

if (isset($arr[4])) $arr[4] = 5;

Check existence.

PHP

<center>output</center>

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

Use CSS.

HTML

jwt.sign({{id:43}}, 'secret');

jwt.sign({{id:43}}, 'secret', {{expiresIn:'7d'}});

Add expiration.

Node.js

items[13]

if (items.indices.contains(13)) items[13]

Check index.

Kotlin

class Order {{ int a; }} obj.a=5;

class Order {{ public int a; }} obj.a=5;

Make field public.

Java

<p>value <b>data</p></b>

<p>value <b>data</b></p>

Nest properly.

HTML

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

Correct.

R

let text1 = String::from("data"); let text2 = text1; println!("{{}}", text1);

let text1 = String::from("data"); let text2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

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

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

Declare before use.

C++

.Item {{ color: #fff; }}

Correct.

CSS

const foo;

const foo = 1;

Initialize const.

JavaScript

fmt.Println 'data'

fmt.Println('data')

Missing parentheses.

Go

ArrayList list = new ArrayList();

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

Use generics.

Java

const http = require('http'); http.createServer((req,res) => res.end('world')).listen(31);

Correct.

Node.js

Use double quotes.

JSON

class Person def method end end

Correct.

Ruby

println('output')

println("output")

Double quotes.

Scala

if (num = 88) {{}}

if (num == 88) {{}}

Use ==.

Kotlin

if bar > 38 puts 'value'

if bar > 38 puts 'value' end

Add 'end'.

Ruby

'info' + 37

'info' + str(37)

Can't add int to string.

Python