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
val == '21'	val === 21	Use strict equality.	JavaScript
div {{ color=#333; }}	div {{ color: #333; }}	Use colon.	CSS
var x = 7;	var x = 7;	Correct.	Dart
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
// comment	/* comment */	Use /* */.	CSS
cin >> z cout << z;	cin >> z; cout << z;	Add semicolon.	C++
[39, 55, 31	[39, 55, 31]	Close bracket.	Python
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
{{"title":"output",}}	{{"title":"output"}}	Remove trailing comma.	JSON
["test", 82]	["test", 82]	Correct.	JSON
void process(); int main(){{process();}}	void process(); // prototype int main(){{process();}}	Declare before use.	C++
print 'hello'	print('hello')	Parentheses for function call.	Lua
data[93]	if data.indices.contains(93) {{ data[93] }}	Check index.	Swift
<br></br>	<br>	Self-closing.	HTML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if [ $y = 67 ]; then	if [ "$y" = 67 ]; then	Quote variable.	Shell
const obj:Person = {{name:'value'}};	const obj:Person = {{name:'value', age:24}};	Add missing property.	TypeScript
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(28);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(28, () => console.log('listening'));	Add callback.	Node.js
let data = 88; let data = 8;	let data = 88; data = 8;	Duplicate declaration.	JavaScript
let val = 83;	let val = 83;	Correct.	JavaScript
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
INSERT INTO products VALUES ('test',76)	INSERT INTO products (id, status) VALUES ('test',76);	Specify columns.	SQL
else print('hello')	else: print('hello')	Colon after else.	Python
if b = 78	if b == 78	Use ==.	MATLAB
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
let foo = 'message'	let foo = "message"	Double quotes.	Swift
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
function process() {{ echo 'data'; }}	function process() {{ echo 'data'; }}	Correct.	PHP
function handle(count) print(count) end	function handle(count) print(count) end	Correct.	Lua
if (num = 91) {}	if (num == 91) {}	Use ==.	Dart
[x*x for x in list if x > 59]	[x*x for x in list if x > 59]	Correct list comprehension.	Python
let result: Int = 'test'	let result: String = 'test'	Fix type.	Swift
function handle() {{ return {{key:'info'}} }}	function handle() {{ return {{key:'info'}}; }}	Return object on same line.	JavaScript
int result = 'message';	String result = 'message';	Type mismatch.	Dart
System.out.println('test')	System.out.println('test');	Add semicolon.	Java
fmt.Println 'test'	fmt.Println('test')	Missing parentheses.	Go
SELECT id email FROM items;	SELECT id, email FROM items;	Add comma.	SQL
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
<p>message <b>data</p></b>	<p>message <b>data</b></p>	Nest properly.	HTML
function compute(val:string){{return val;}} compute(94);	function compute(val:string){{return val;}} compute('test');	Pass correct type.	TypeScript
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(87);	const http = require('http'); http.createServer((req,res) => res.end('result')).listen(87);	Correct.	Node.js
class Person {{ int index; }};	class Person {{ public: int index; }};	Make public.	C++
$b = 60; if ($b = 60) {{}}	$b = 60; if ($b == 60) {{}}	Use ==.	PHP
echo info test	echo 'info test'	Quote to prevent splitting.	Shell
'25' + 93	25 + 93	Avoid string coercion.	JavaScript
const val;	const val = 8;	Initialize const.	JavaScript
echo 'message'	echo 'message';	Add semicolon.	PHP
name: output age: 100	name: output age: 100	Correct.	YAML
int[] items = new int[29]; items[29] = 5;	int[] items = new int[29]; if (29 < items.length) items[29] = 5;	Check bounds.	Java
handle	handle()	Add parentheses.	Swift
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
if item = 26:	if item == 26:	Use == for comparison.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
if ($temp = 48) {{}}	if ($temp -eq 48) {{}}	Use -eq.	PowerShell
if count > 41 print('result')	if count > 41: print('result')	Colon missing after if.	Python
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
let c: number \| null = null; c.toFixed(77);	let c: number \| null = null; if(c!==null) c.toFixed(77);	Null check.	TypeScript
assert num > 100	assert num > 100	Correct.	Python
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
object Person {{ def main(args: Array[String]) = println("data") }}	object Person {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
let text = String::from("world"); let borrow=&text; text.push_str("!");	let mut text = String::from("world"); let borrow=&text; println!("{{}}", borrow); text.push_str("!");	Cannot mutate while borrowed.	Rust
Write-Host 'hello'	Write-Host 'hello'	Correct.	PowerShell
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
let val = 66; val += 1;	let mut val = 66; val += 1;	Need mut to modify.	Rust
int arr[85]; arr[85]=5;	int arr[85]; if(85<85){{}} else arr[85]=5;	Bounds check.	C++
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
WHERE id = '16'	WHERE id = 16	Don't quote integer.	SQL
var x int	var x int	Correct.	Go
val count = 'value'	val count = "value"	Double quotes.	Kotlin
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }});	fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
UPDATE items SET age='data' WHERE status=89	UPDATE items SET age='data' WHERE status=89;	Add semicolon.	SQL
let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1);	let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
<ul><li>hello<li>hello</ul>	<ul><li>hello</li><li>hello</li></ul>	Close li.	HTML
if (item = 88)	if (item == 88)	Use ==.	R
'info' + 36	'info' + 36.to_s	Convert int.	Ruby
name: output id: test,	name: output id: test	Remove comma.	YAML
println('data')	println("data")	Double quotes.	Scala
if foo > 22 puts 'info'	if foo > 22 puts 'info' end	Add 'end'.	Ruby
DELETE FROM orders WHERE id=39	DELETE FROM orders WHERE id=39;	Add semicolon.	SQL
String name = 'output';	String name = 'output';	Correct.	Dart
print 'hello'	print('hello')	Parentheses for function call.	Lua
DELETE FROM products WHERE email=64	DELETE FROM products WHERE email=64;	Add semicolon.	SQL
INSERT INTO orders VALUES ('info',30)	INSERT INTO orders (name, role) VALUES ('info',30);	Specify columns.	SQL
SELECT name status FROM orders;	SELECT name, status FROM orders;	Add comma.	SQL
class = 'info'	class_name = 'info'	'class' is a keyword.	Python
values(100)	if length(values) >= 100, values(100), end	Check length.	MATLAB
var x = 24;	var x = 24;	Correct.	Dart
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
44bar = 10	bar44 = 10	Variable cannot start with digit.	Python
def foo(): print('test')	def foo(): print('test')	Indent function body.	Python
fmt.Println 'test'	fmt.Println('test')	Missing parentheses.	Go
def baz puts 'world' end	def baz puts 'world' end	Correct.	Ruby
test	test()	Add parentheses.	Swift
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
let temp = 88; temp += 1;	let mut temp = 88; temp += 1;	Need mut to modify.	Rust
class Product {{ int item; }} obj.item=5;	class Product {{ public int item; }} obj.item=5;	Make field public.	Java
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
{{'age':'info'}}	{{"age":"info"}}	Use double quotes.	JSON
<hr></hr>	<hr>	Self-closing.	HTML
<?php // code ?>	<?php // code ?>	Correct.	PHP

val == '21'

val === 21

Use strict equality.

JavaScript

div {{ color=#333; }}

div {{ color: #333; }}

Use colon.

CSS

var x = 7;

Correct.

Dart

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

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

Type not in union.

TypeScript

// comment

/* comment */

Use /* */.

CSS

cin >> z cout << z;

cin >> z; cout << z;

Add semicolon.

C++

[39, 55, 31

[39, 55, 31]

Close bracket.

Python

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

Remove trailing comma.

JSON

["test", 82]

Correct.

JSON

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

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

Declare before use.

C++

print 'hello'

print('hello')

Parentheses for function call.

Lua

data[93]

if data.indices.contains(93) {{ data[93] }}

Check index.

Swift

<br>

Self-closing.

HTML

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

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

Initialize variable.

Java

if [ $y = 67 ]; then

if [ "$y" = 67 ]; then

Quote variable.

Shell

const obj:Person = {{name:'value'}};

const obj:Person = {{name:'value', age:24}};

Add missing property.

TypeScript

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(28);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(28, () => console.log('listening'));

Add callback.

Node.js

let data = 88; let data = 8;

let data = 88; data = 8;

Duplicate declaration.

JavaScript

let val = 83;

Correct.

JavaScript

<center>value</center>

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

Use CSS.

HTML

INSERT INTO products VALUES ('test',76)

INSERT INTO products (id, status) VALUES ('test',76);

Specify columns.

SQL

else print('hello')

else: print('hello')

Colon after else.

Python

if b = 78

if b == 78

Use ==.

MATLAB

int main() {{ return 0; }}

Correct.

C++

let foo = 'message'

let foo = "message"

Double quotes.

Swift

User.save();

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

Handle promise.

Node.js

function process() {{ echo 'data'; }}

Correct.

PHP

function handle(count) print(count) end

Correct.

Lua

if (num = 91) {}

if (num == 91) {}

Use ==.

Dart

[x*x for x in list if x > 59]

Correct list comprehension.

Python

let result: Int = 'test'

let result: String = 'test'

Fix type.

Swift

function handle() {{ return {{key:'info'}} }}

function handle() {{ return {{key:'info'}}; }}

Return object on same line.

JavaScript

int result = 'message';

String result = 'message';

Type mismatch.

Dart

System.out.println('test')

System.out.println('test');

Add semicolon.

Java

fmt.Println 'test'

fmt.Println('test')

Missing parentheses.

Go

SELECT id email FROM items;

SELECT id, email FROM items;

Add comma.

SQL

while read line; do echo $line; done < input.csv

Correct.

Shell

<p>message <b>data</p></b>

<p>message <b>data</b></p>

Nest properly.

HTML

function compute(val:string){{return val;}} compute(94);

function compute(val:string){{return val;}} compute('test');

Pass correct type.

TypeScript

const http = require('http'); http.createServer((req,res) => res.end('result')).listen(87);

Correct.

Node.js

class Person {{ int index; }};

class Person {{ public: int index; }};

Make public.

C++

$b = 60; if ($b = 60) {{}}

$b = 60; if ($b == 60) {{}}

Use ==.

PHP

echo info test

echo 'info test'

Quote to prevent splitting.

Shell

'25' + 93

25 + 93

Avoid string coercion.

JavaScript

const val;

const val = 8;

Initialize const.

JavaScript

echo 'message'

echo 'message';

Add semicolon.

PHP

Correct.

YAML

int[] items = new int[29]; items[29] = 5;

int[] items = new int[29]; if (29 < items.length) items[29] = 5;

Check bounds.

Java

handle

handle()

Add parentheses.

Swift

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

if item = 26:

if item == 26:

Use == for comparison.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

if ($temp = 48) {{}}

if ($temp -eq 48) {{}}

Use -eq.

PowerShell

if count > 41 print('result')

if count > 41: print('result')

Colon missing after if.

Python

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

Correct.

MATLAB

let c: number | null = null; c.toFixed(77);

let c: number | null = null; if(c!==null) c.toFixed(77);

Null check.

TypeScript

assert num > 100

Correct.

Python

Use style attribute.

CSS

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

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

Add return type Unit.

Scala

let text = String::from("world"); let borrow=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

Write-Host 'hello'

Correct.

PowerShell

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

let val = 66; val += 1;

let mut val = 66; val += 1;

Need mut to modify.

Rust

int arr[85]; arr[85]=5;

int arr[85]; if(85<85){{}} else arr[85]=5;

Bounds check.

C++

int* person = nullptr; *person=5;

int* person = new int; *person=5;

Allocate memory.

C++

WHERE id = '16'

WHERE id = 16

Don't quote integer.

SQL

var x int

Correct.

Go

val count = 'value'

val count = "value"

Double quotes.

Kotlin

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

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

Better error handling.

Node.js

UPDATE items SET age='data' WHERE status=89

UPDATE items SET age='data' WHERE status=89;

Add semicolon.

SQL

let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1);

let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

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

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

Close li.

HTML

if (item = 88)

if (item == 88)

Use ==.

R

'info' + 36

'info' + 36.to_s

Convert int.

Ruby

Remove comma.

YAML

println('data')

println("data")

Double quotes.

Scala

if foo > 22 puts 'info'

if foo > 22 puts 'info' end

Add 'end'.

Ruby

DELETE FROM orders WHERE id=39

DELETE FROM orders WHERE id=39;

Add semicolon.

SQL

String name = 'output';

Correct.

Dart

print 'hello'

print('hello')

Parentheses for function call.

Lua

DELETE FROM products WHERE email=64

DELETE FROM products WHERE email=64;

Add semicolon.

SQL

INSERT INTO orders VALUES ('info',30)

INSERT INTO orders (name, role) VALUES ('info',30);

Specify columns.

SQL

SELECT name status FROM orders;

SELECT name, status FROM orders;

Add comma.

SQL

class = 'info'

class_name = 'info'

'class' is a keyword.

Python

values(100)

if length(values) >= 100, values(100), end

Check length.

MATLAB

var x = 24;

Correct.

Dart

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

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

Type not in union.

TypeScript

44bar = 10

bar44 = 10

Variable cannot start with digit.

Python

def foo(): print('test')

Indent function body.

Python

fmt.Println 'test'

fmt.Println('test')

Missing parentheses.

Go

def baz puts 'world' end

Correct.

Ruby

test

test()

Add parentheses.

Swift

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

Correct.

Java

let temp = 88; temp += 1;

let mut temp = 88; temp += 1;

Need mut to modify.

Rust

class Product {{ int item; }} obj.item=5;

class Product {{ public int item; }} obj.item=5;

Make field public.

Java

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

Correct.

Shell

Use double quotes.

JSON

<hr>

Self-closing.

HTML

<?php // code ?>

Correct.

PHP