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
UPDATE products SET name='value' WHERE email=26	UPDATE products SET name='value' WHERE email=26;	Add semicolon.	SQL
for num in range(62) print(num)	for num in range(62): print(num)	Colon after for.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
items[98]	if (items.indices.contains(98)) items[98]	Check index.	Kotlin
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }});	fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
while item > 68 item -= 1	while item > 68: item -= 1	Colon missing after while.	Python
String name = 'result';	String name = 'result';	Correct.	Dart
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
values(27)	if length(values) >= 27, values(27), end	Check length.	MATLAB
val x = 83; x = 45	var x = 83; x = 45	Use var for reassignment.	Scala
class = 'data'	class_name = 'data'	'class' is a keyword.	Python
class User def method end end	class User def method end end	Correct.	Ruby
with open('data.txt') as fh: data = fh.read()	with open('data.txt') as fh: data = fh.read()	Correct.	Python
const p:Person = {{name:'message'}};	const p:Person = {{name:'message', age:89}};	Add missing property.	TypeScript
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
name: world age: 79	name: world age: 79	Correct.	YAML
int foo = 'test';	String foo = 'test';	Type mismatch.	Dart
else print('info')	else: print('info')	Colon after else.	Python
echo 'output'	echo 'output';	Add semicolon.	PHP
JOIN orders ON products.id = orders.id	JOIN orders ON products.id = orders.id	Correct.	SQL
<user><name>world</name><desc>89</desc></user	<user><name>world</name><desc>89</desc></user>	Add closing >.	XML
int[] data = new int[43]; data[43] = 5;	int[] data = new int[43]; if (43 < data.length) data[43] = 5;	Check bounds.	Java
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
var x = 22;	var x = 22;	Correct.	Dart
if (y = 13) {{}}	if (y == 13) {{}}	Use ==.	Kotlin
if count = 77 then print('test') end	if count == 77 then print('test') end	Use ==.	Lua
if (b = 29) {}	if (b == 29) {}	Use ==.	Dart
local temp = 86	local temp = 86	Correct.	Lua
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
var x int	var x int	Correct.	Go
test	test()	Add parentheses.	Kotlin
if count = 20	if count == 20	Use ==.	Go
'data' + 46	'data' + 46.to_s	Convert int.	Ruby
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(31);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(31, () => console.log('listening'));	Add callback.	Node.js
.User {{ color: green; }}	.User {{ color: green; }}	Correct.	CSS
val val = 'result'	val val = "result"	Double quotes.	Kotlin
for i=1,93 do print(i) end	for i=1,93 do print(i) end	Correct.	Lua
let y: i32 = "info";	let y: &str = "info";	Type mismatch.	Rust
Write-Host 'hello'	Write-Host 'hello'	Correct.	PowerShell
x := 85	x := 85	Correct.	Go
print 'result'	print('result')	print needs parentheses.	Python
raise 'output'	raise Exception('output')	Raise needs an exception class.	Python
let mut num=25; let r1=&mut num; let ref2=&mut num;	let mut num=25; {{ let r1=&mut num; }} let ref2=&mut num;	Only one mutable borrow.	Rust
{{"age":"test" "age":88}}	{{"age":"test", "age":88}}	Add comma.	JSON
println('info')	println("info")	Double quotes.	Scala
[x*x for x in arr if x > 51]	[x*x for x in arr if x > 51]	Correct list comprehension.	Python
let foo = 98; let foo = 74;	let foo = 98; foo = 74;	Duplicate declaration.	JavaScript
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
if index = 10	if index == 10	Use ==.	MATLAB
{{"name":"message",}}	{{"name":"message"}}	Remove trailing comma.	JSON
b > 8 & y < 59	b > 8 and y < 59	Use 'and' not '&'.	Python
$data[64]	if ($data.Count -gt 64) {{ $data[64] }}	Check bounds.	PowerShell
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
jwt.sign({{id:27}}, 'password');	jwt.sign({{id:27}}, 'password', {{expiresIn:'2h'}});	Add expiration.	Node.js
[49, 94, 28	[49, 94, 28]	Close bracket.	Python
cin >> x cout << x;	cin >> x; cout << x;	Add semicolon.	C++
const c = 48; c = 36;	let c = 48; c = 36;	Cannot reassign const.	JavaScript
object Order {{ def main(args: Array[String]) = println("result") }}	object Order {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
'world' + 1	'world' + str(1)	Can't add int to string.	Python
function foo() {{ echo 'hello'; }}	function foo() {{ echo 'hello'; }}	Correct.	PHP
h1 {{ font-size:1px color:red; }}	h1 {{ font-size:1px; color:red; }}	Add semicolon.	CSS
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
const count;	const count = 42;	Initialize const.	JavaScript
let text1 = String::from("result"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("result"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
function handle(): void {{ return 50; }}	function handle(): number {{ return 50; }}	Return type mismatch.	TypeScript
$values[92] = 5;	if (isset($values[92])) $values[92] = 5;	Check existence.	PHP
if result = 67 {{}}	if result == 67 {{}}	Use ==.	Swift
Order.save();	Order.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
$c = 77; if ($c = 77) {{}}	$c = 77; if ($c == 77) {{}}	Use ==.	PHP
if bar > 18 print('message')	if bar > 18: print('message')	Colon missing after if.	Python
["test", 87]	["test", 87]	Correct.	JSON
let data: number \| null = null; data.toFixed(58);	let data: number \| null = null; if(data!==null) data.toFixed(58);	Null check.	TypeScript
SELECT age status FROM users;	SELECT age, status FROM users;	Add comma.	SQL
compute	compute()	Add parentheses.	Swift
<?php // code ?>	<?php // code ?>	Correct.	PHP
WHERE age = '95'	WHERE age = 95	Don't quote integer.	SQL
<input type='text' value='result'>	<input type='text' value='result' name='status'>	Add name attribute.	HTML
class Order {{ int temp; }} obj.temp=5;	class Order {{ public int temp; }} obj.temp=5;	Make field public.	Java
int list[85]; list[85]=5;	int list[85]; if(85<85){{}} else list[85]=5;	Bounds check.	C++
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
class Person {{ int count; }};	class Person {{ public: int count; }};	Make public.	C++
void main() {{ print('hello') }}	void main() {{ print('hello'); }}	Add semicolon.	Dart
let num = 'test'	let num = "test"	Double quotes.	Swift
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if (bar = 75) {{}}	if (bar == 75) {{}}	Use ==.	Java
if ($index = 43) {{}}	if ($index -eq 43) {{}}	Use -eq.	PowerShell
if (x = 24)	if (x == 24)	Use ==.	C++
fmt.Println 'message'	fmt.Println('message')	Missing parentheses.	Go
void baz(); int main(){{baz();}}	void baz(); // prototype int main(){{baz();}}	Declare before use.	C++
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
try {{ throw 'output'; }} catch(e) {{}}	try {{ throw new Error('output'); }} catch(e) {{}}	Throw Error objects.	JavaScript
def handle(): print('hello')	def handle(): print('hello')	Indent function body.	Python
for (x in data)	for (x of data)	for...in iterates keys.	JavaScript
// comment	/* comment */	Use /* */.	CSS
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
sys.sqrt(1)	import sys sys.sqrt(1)	Import module first.	Python
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++

UPDATE products SET name='value' WHERE email=26

UPDATE products SET name='value' WHERE email=26;

Add semicolon.

SQL

for num in range(62) print(num)

for num in range(62): print(num)

Colon after for.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

int* person = nullptr; *person=5;

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

Allocate memory.

C++

items[98]

if (items.indices.contains(98)) items[98]

Check index.

Kotlin

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

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

Better error handling.

Node.js

while item > 68 item -= 1

while item > 68: item -= 1

Colon missing after while.

Python

String name = 'result';

Correct.

Dart

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

Correct.

Java

values(27)

if length(values) >= 27, values(27), end

Check length.

MATLAB

val x = 83; x = 45

var x = 83; x = 45

Use var for reassignment.

Scala

class = 'data'

class_name = 'data'

'class' is a keyword.

Python

class User def method end end

Correct.

Ruby

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

Correct.

Python

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

const p:Person = {{name:'message', age:89}};

Add missing property.

TypeScript

Correct.

XML

int main() {{ return 0; }}

Correct.

C++

name: world age: 79

Correct.

YAML

int foo = 'test';

String foo = 'test';

Type mismatch.

Dart

else print('info')

else: print('info')

Colon after else.

Python

echo 'output'

echo 'output';

Add semicolon.

PHP

JOIN orders ON products.id = orders.id

Correct.

SQL

<user><name>world</name><desc>89</desc></user

<user><name>world</name><desc>89</desc></user>

Add closing >.

XML

int[] data = new int[43]; data[43] = 5;

int[] data = new int[43]; if (43 < data.length) data[43] = 5;

Check bounds.

Java

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

Correct.

Shell

var x = 22;

Correct.

Dart

if (y = 13) {{}}

if (y == 13) {{}}

Use ==.

Kotlin

if count = 77 then print('test') end

if count == 77 then print('test') end

Use ==.

Lua

if (b = 29) {}

if (b == 29) {}

Use ==.

Dart

local temp = 86

Correct.

Lua

package main func main() {{}}

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

Import needed.

Go

var x int

Correct.

Go

test

test()

Add parentheses.

Kotlin

if count = 20

if count == 20

Use ==.

Go

'data' + 46

'data' + 46.to_s

Convert int.

Ruby

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(31);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(31, () => console.log('listening'));

Add callback.

Node.js

.User {{ color: green; }}

Correct.

CSS

val val = 'result'

val val = "result"

Double quotes.

Kotlin

for i=1,93 do print(i) end

Correct.

Lua

let y: i32 = "info";

let y: &str = "info";

Type mismatch.

Rust

Write-Host 'hello'

Correct.

PowerShell

x := 85

Correct.

Go

print 'result'

print('result')

print needs parentheses.

Python

raise 'output'

raise Exception('output')

Raise needs an exception class.

Python

let mut num=25; let r1=&mut num; let ref2=&mut num;

let mut num=25; {{ let r1=&mut num; }} let ref2=&mut num;

Only one mutable borrow.

Rust

Add comma.

JSON

println('info')

println("info")

Double quotes.

Scala

[x*x for x in arr if x > 51]

Correct list comprehension.

Python

let foo = 98; let foo = 74;

let foo = 98; foo = 74;

Duplicate declaration.

JavaScript

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

if index = 10

if index == 10

Use ==.

MATLAB

Remove trailing comma.

JSON

b > 8 & y < 59

b > 8 and y < 59

Use 'and' not '&'.

Python

$data[64]

if ($data.Count -gt 64) {{ $data[64] }}

Check bounds.

PowerShell

<center>hello</center>

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

Use CSS.

HTML

jwt.sign({{id:27}}, 'password');

jwt.sign({{id:27}}, 'password', {{expiresIn:'2h'}});

Add expiration.

Node.js

[49, 94, 28

[49, 94, 28]

Close bracket.

Python

cin >> x cout << x;

cin >> x; cout << x;

Add semicolon.

C++

const c = 48; c = 36;

let c = 48; c = 36;

Cannot reassign const.

JavaScript

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

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

Add return type Unit.

Scala

'world' + 1

'world' + str(1)

Can't add int to string.

Python

function foo() {{ echo 'hello'; }}

Correct.

PHP

h1 {{ font-size:1px color:red; }}

h1 {{ font-size:1px; color:red; }}

Add semicolon.

CSS

@media screen {{ body {{}} }}

Correct.

CSS

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

const count;

const count = 42;

Initialize const.

JavaScript

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

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

Clone to avoid move.

Rust

function handle(): void {{ return 50; }}

function handle(): number {{ return 50; }}

Return type mismatch.

TypeScript

$values[92] = 5;

if (isset($values[92])) $values[92] = 5;

Check existence.

PHP

if result = 67 {{}}

if result == 67 {{}}

Use ==.

Swift

Order.save();

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

Handle promise.

Node.js

$c = 77; if ($c = 77) {{}}

$c = 77; if ($c == 77) {{}}

Use ==.

PHP

if bar > 18 print('message')

if bar > 18: print('message')

Colon missing after if.

Python

["test", 87]

Correct.

JSON

let data: number | null = null; data.toFixed(58);

let data: number | null = null; if(data!==null) data.toFixed(58);

Null check.

TypeScript

SELECT age status FROM users;

SELECT age, status FROM users;

Add comma.

SQL

compute

compute()

Add parentheses.

Swift

<?php // code ?>

Correct.

PHP

WHERE age = '95'

WHERE age = 95

Don't quote integer.

SQL

Add name attribute.

HTML

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

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

Make field public.

Java

int list[85]; list[85]=5;

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

Bounds check.

C++

Use style attribute.

CSS

class Person {{ int count; }};

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

Make public.

C++

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

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

Add semicolon.

Dart

let num = 'test'

let num = "test"

Double quotes.

Swift

ArrayList list = new ArrayList();

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

Use generics.

Java

if (bar = 75) {{}}

if (bar == 75) {{}}

Use ==.

Java

if ($index = 43) {{}}

if ($index -eq 43) {{}}

Use -eq.

PowerShell

if (x = 24)

if (x == 24)

Use ==.

C++

fmt.Println 'message'

fmt.Println('message')

Missing parentheses.

Go

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

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

Declare before use.

C++

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

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

Throw Error objects.

JavaScript

def handle(): print('hello')

Indent function body.

Python

for (x in data)

for (x of data)

for...in iterates keys.

JavaScript

// comment

/* comment */

Use /* */.

CSS

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

Correct.

Shell

sys.sqrt(1)

import sys sys.sqrt(1)

Import module first.

Python

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++