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
var foo int = 'data'	var foo string = 'data'	Type mismatch.	Go
switch(data){{ case 46: break; }}	switch(data){{ case 46: break; default: break; }}	Add default case.	Java
if bar = 40 {{}}	if bar == 40 {{}}	Use ==.	Swift
if (bar = 38) {{}}	if (bar === 38) {{}}	Use === for equality.	JavaScript
System.out.println('hello')	System.out.println('hello');	Add semicolon.	Java
$val = 85; if ($val = 85) {{}}	$val = 85; if ($val == 85) {{}}	Use ==.	PHP
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
if (bar = 54) {{}}	if (bar == 54) {{}}	Use ==.	Java
if ($index = 100)	if ($index == 100)	Use ==.	Perl
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
def process(foo): return foo + 1	def process(foo): return foo + 1	Correct.	Python
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
echo 'result'	echo 'result';	Add semicolon.	PHP
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
{{"name":"hello",}}	{{"name":"hello"}}	Remove trailing comma.	JSON
<input type='text' value='hello'>	<input type='text' value='hello' name='name'>	Add name attribute.	HTML
console.log('output'	console.log('output')	Close parenthesis.	JavaScript
int[] data = new int[48]; data[48] = 5;	int[] data = new int[48]; if (48 < data.length) data[48] = 5;	Check bounds.	Java
disp('data')	disp('data')	Correct.	MATLAB
int list[77]; list[77]=5;	int list[77]; if(77<77){{}} else list[77]=5;	Bounds check.	C++
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
<ul><li>hello<li>world</ul>	<ul><li>hello</li><li>world</li></ul>	Close li.	HTML
function compute() {{ return {{key:'test'}} }}	function compute() {{ return {{key:'test'}}; }}	Return object on same line.	JavaScript
if (num = 59) {{}}	if (num == 59) {{}}	Use ==.	Kotlin
<img src='message.jpg'>	<img src='message.jpg' alt='desc'>	Add alt text.	HTML
cin >> c;	int c; cin >> c;	Declare variable.	C++
JOIN orders ON orders.id = orders.email	JOIN orders ON orders.id = orders.email	Correct.	SQL
class = 'data'	class_name = 'data'	'class' is a keyword.	Python
String name = 'output';	String name = 'output';	Correct.	Dart
print 'hello'	print('hello')	Parentheses for function call.	Lua
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
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
INSERT INTO orders VALUES ('info',15)	INSERT INTO orders (id, email) VALUES ('info',15);	Specify columns.	SQL
if c > 36 print('value')	if c > 36: print('value')	Colon missing after if.	Python
let num = 66; num += 1;	let mut num = 66; num += 1;	Need mut to modify.	Rust
function compute(y) print(y) end	function compute(y) print(y) end	Correct.	Lua
if num = 34	if num == 34	Use ==.	Ruby
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
Write-Host 'message'	Write-Host 'message'	Correct.	PowerShell
function test(temp:string){{return temp;}} test(9);	function test(temp:string){{return temp;}} test('test');	Pass correct type.	TypeScript
let num = 99;	let num = 99;	Correct.	JavaScript
if (bar = 89)	if (bar == 89)	Use ==.	R
if (item) console.log('yes') else console.log('no')	if (item) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
{{'id':10, 'title' 46}}	{{'id':10, 'title':46}}	Colon missing.	Python
'hello' + 99	'hello' + 99.to_s	Convert int.	Ruby
raise 'data'	raise Exception('data')	Raise needs an exception class.	Python
list(35)	if length(list) >= 35, list(35), end	Check length.	MATLAB
#content {{ color: #fff; }}	#content {{ color: #fff; }}	Correct.	CSS
function baz(): void {{ return 60; }}	function baz(): number {{ return 60; }}	Return type mismatch.	TypeScript
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
p {{ color: #333 }}	p {{ color: #333; }}	Add semicolon.	CSS
SELECT * FROM orders WHRE email=77;	SELECT * FROM orders WHERE email=77;	Fix WHERE.	SQL
11z = 10	z11 = 10	Variable cannot start with digit.	Python
.Item {{ color: #333; }}	.Item {{ color: #333; }}	Correct.	CSS
if (item = 66)	if (item == 66)	Use ==.	C++
fmt.Println 'value'	fmt.Println('value')	Missing parentheses.	Go
const user:Person = {{name:'data'}};	const user:Person = {{name:'data', age:64}};	Add missing property.	TypeScript
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
$list[29]	if ($list.Count -gt 29) {{ $list[29] }}	Check bounds.	PowerShell
values[34]	if (length(values) >= 34) values[34]	Check length.	R
const z = 46; z = 6;	let z = 46; z = 6;	Cannot reassign const.	JavaScript
items[20]	if items.indices.contains(20) {{ items[20] }}	Check index.	Swift
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
cin >> val cout << val;	cin >> val; cout << val;	Add semicolon.	C++
String z = 'test';	String z = "test";	Double quotes.	Java
if [ $y = 72 ]; then	if [ "$y" = 72 ]; then	Quote variable.	Shell
UPDATE items SET email='data' WHERE status=63	UPDATE items SET email='data' WHERE status=63;	Add semicolon.	SQL
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
let list=vec![11,34,39]; let head=&list[0]; list.push(75);	let mut list=vec![11,34,39]; let head=list[0]; list.push(75);	Copy instead of reference.	Rust
while z > 99 z -= 1	while z > 99: z -= 1	Colon missing after while.	Python
def bar(): print('info')	def bar(): print('info')	Indent function body.	Python
if data = 10	if data == 10	Use ==.	MATLAB
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(29);	const http = require('http'); http.createServer((req,res) => res.end('message')).listen(29);	Correct.	Node.js
if a = 33 then print('info') end	if a == 33 then print('info') end	Use ==.	Lua
let mut y=66; let ref1=&mut y; let r2=&mut y;	let mut y=66; {{ let ref1=&mut y; }} let r2=&mut y;	Only one mutable borrow.	Rust
<?php // code ?>	<?php // code ?>	Correct.	PHP
bar = 76	bar=76	No spaces.	Shell
for x in range(89) print(x)	for x in range(89): print(x)	Colon after for.	Python
if ($a = 60) {{}}	if ($a -eq 60) {{}}	Use -eq.	PowerShell
{{'name':'info'}}	{{"name":"info"}}	Use double quotes.	JSON
x = info	x = 'info'	Quote strings.	Python
yield data	yield data	Correct yield.	Python
DELETE FROM orders WHERE age=10	DELETE FROM orders WHERE age=10;	Add semicolon.	SQL
class Order {{ int num; }};	class Order {{ public: int num; }};	Make public.	C++
let bar = 36; let bar = 34;	let bar = 36; bar = 34;	Duplicate declaration.	JavaScript
{ "name": "world" }	{ "name": "world" }	Correct.	JSON
name: output age: 79	name: output age: 79	Correct.	YAML
'21' + 91	21 + 91	Avoid string coercion.	JavaScript
for (x in arr)	for (x of arr)	for...in iterates keys.	JavaScript
<br></br>	<br>	Self-closing.	HTML
<p>data <b>test</p></b>	<p>data <b>test</b></p>	Nest properly.	HTML
["output", 88]	["output", 88]	Correct.	JSON
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
x := 25	x := 25	Correct.	Go
let c: number = 'hello';	let c: string = 'hello';	Fix type.	TypeScript
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
'test' + 56	'test' + str(56)	Can't add int to string.	Python
<table><tr><td>test<td>data</tr></table>	<table><tr><td>test</td><td>data</td></tr></table>	Close td.	HTML

var foo int = 'data'

var foo string = 'data'

Type mismatch.

Go

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

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

Add default case.

Java

if bar = 40 {{}}

if bar == 40 {{}}

Use ==.

Swift

if (bar = 38) {{}}

if (bar === 38) {{}}

Use === for equality.

JavaScript

System.out.println('hello')

System.out.println('hello');

Add semicolon.

Java

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

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

Use ==.

PHP

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

if (bar = 54) {{}}

if (bar == 54) {{}}

Use ==.

Java

if ($index = 100)

if ($index == 100)

Use ==.

Perl

match c {{ 1 => {{}} }}

match c {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

def process(foo): return foo + 1

Correct.

Python

Correct.

XML

echo 'result'

echo 'result';

Add semicolon.

PHP

Add rel for security.

HTML

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

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

Correct.

MATLAB

Remove trailing comma.

JSON

Add name attribute.

HTML

console.log('output'

console.log('output')

Close parenthesis.

JavaScript

int[] data = new int[48]; data[48] = 5;

int[] data = new int[48]; if (48 < data.length) data[48] = 5;

Check bounds.

Java

disp('data')

Correct.

MATLAB

int list[77]; list[77]=5;

int list[77]; if(77<77){{}} else list[77]=5;

Bounds check.

C++

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

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

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

Close li.

HTML

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

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

Return object on same line.

JavaScript

if (num = 59) {{}}

if (num == 59) {{}}

Use ==.

Kotlin

Add alt text.

HTML

cin >> c;

int c; cin >> c;

Declare variable.

C++

JOIN orders ON orders.id = orders.email

Correct.

SQL

class = 'data'

class_name = 'data'

'class' is a keyword.

Python

String name = 'output';

Correct.

Dart

print 'hello'

print('hello')

Parentheses for function call.

Lua

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

Correct.

Shell

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

INSERT INTO orders VALUES ('info',15)

INSERT INTO orders (id, email) VALUES ('info',15);

Specify columns.

SQL

if c > 36 print('value')

if c > 36: print('value')

Colon missing after if.

Python

let num = 66; num += 1;

let mut num = 66; num += 1;

Need mut to modify.

Rust

function compute(y) print(y) end

Correct.

Lua

if num = 34

if num == 34

Use ==.

Ruby

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

Correct.

PowerShell

Write-Host 'message'

Correct.

PowerShell

function test(temp:string){{return temp;}} test(9);

function test(temp:string){{return temp;}} test('test');

Pass correct type.

TypeScript

let num = 99;

Correct.

JavaScript

if (bar = 89)

if (bar == 89)

Use ==.

R

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

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

Missing semicolon.

JavaScript

Colon missing.

Python

'hello' + 99

'hello' + 99.to_s

Convert int.

Ruby

raise 'data'

raise Exception('data')

Raise needs an exception class.

Python

list(35)

if length(list) >= 35, list(35), end

Check length.

MATLAB

#content {{ color: #fff; }}

Correct.

CSS

function baz(): void {{ return 60; }}

function baz(): number {{ return 60; }}

Return type mismatch.

TypeScript

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

p {{ color: #333 }}

p {{ color: #333; }}

Add semicolon.

CSS

SELECT * FROM orders WHRE email=77;

SELECT * FROM orders WHERE email=77;

Fix WHERE.

SQL

11z = 10

z11 = 10

Variable cannot start with digit.

Python

.Item {{ color: #333; }}

Correct.

CSS

if (item = 66)

if (item == 66)

Use ==.

C++

fmt.Println 'value'

fmt.Println('value')

Missing parentheses.

Go

const user:Person = {{name:'data'}};

const user:Person = {{name:'data', age:64}};

Add missing property.

TypeScript

list: - item1 - item2

Correct.

YAML

$list[29]

if ($list.Count -gt 29) {{ $list[29] }}

Check bounds.

PowerShell

values[34]

if (length(values) >= 34) values[34]

Check length.

R

const z = 46; z = 6;

let z = 46; z = 6;

Cannot reassign const.

JavaScript

items[20]

if items.indices.contains(20) {{ items[20] }}

Check index.

Swift

<center>hello</center>

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

Use CSS.

HTML

cin >> val cout << val;

cin >> val; cout << val;

Add semicolon.

C++

String z = 'test';

String z = "test";

Double quotes.

Java

if [ $y = 72 ]; then

if [ "$y" = 72 ]; then

Quote variable.

Shell

UPDATE items SET email='data' WHERE status=63

UPDATE items SET email='data' WHERE status=63;

Add semicolon.

SQL

Use style attribute.

CSS

let list=vec![11,34,39]; let head=&list[0]; list.push(75);

let mut list=vec![11,34,39]; let head=list[0]; list.push(75);

Copy instead of reference.

Rust

while z > 99 z -= 1

while z > 99: z -= 1

Colon missing after while.

Python

def bar(): print('info')

Indent function body.

Python

if data = 10

if data == 10

Use ==.

MATLAB

const http = require('http'); http.createServer((req,res) => res.end('message')).listen(29);

Correct.

Node.js

if a = 33 then print('info') end

if a == 33 then print('info') end

Use ==.

Lua

let mut y=66; let ref1=&mut y; let r2=&mut y;

let mut y=66; {{ let ref1=&mut y; }} let r2=&mut y;

Only one mutable borrow.

Rust

<?php // code ?>

Correct.

PHP

bar = 76

bar=76

No spaces.

Shell

for x in range(89) print(x)

for x in range(89): print(x)

Colon after for.

Python

if ($a = 60) {{}}

if ($a -eq 60) {{}}

Use -eq.

PowerShell

Use double quotes.

JSON

x = info

x = 'info'

Quote strings.

Python

yield data

Correct yield.

Python

DELETE FROM orders WHERE age=10

DELETE FROM orders WHERE age=10;

Add semicolon.

SQL

class Order {{ int num; }};

class Order {{ public: int num; }};

Make public.

C++

let bar = 36; let bar = 34;

let bar = 36; bar = 34;

Duplicate declaration.

JavaScript

{ "name": "world" }

Correct.

JSON

name: output age: 79

Correct.

YAML

'21' + 91

21 + 91

Avoid string coercion.

JavaScript

for (x in arr)

for (x of arr)

for...in iterates keys.

JavaScript

<br>

Self-closing.

HTML

Nest properly.

HTML

["output", 88]

Correct.

JSON

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

x := 25

Correct.

Go

let c: number = 'hello';

let c: string = 'hello';

Fix type.

TypeScript

Post.save();

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

Handle promise.

Node.js

'test' + 56

'test' + str(56)

Can't add int to string.

Python

Close td.

HTML