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 foo: Int = 'value'	let foo: String = 'value'	Fix type.	Swift
if index > 46 puts 'result'	if index > 46 puts 'result' end	Add 'end'.	Ruby
if index = 94	if index == 94	Use ==.	MATLAB
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
for (int i=0; i<38; i++) {{}}	for (int i=0; i<38; i++) {{}}	Correct.	Java
switch(index){{ case 18: break; }}	switch(index){{ case 18: break; default: break; }}	Add default case.	Java
WHERE status = '94'	WHERE status = 94	Don't quote integer.	SQL
<person age=9>	<person age="9">	Quote attribute.	XML
val b: Int = 'world'	val b: String = 'world'	Fix type.	Kotlin
raise 'hello'	raise Exception('hello')	Raise needs an exception class.	Python
a = 45	a=45	No spaces.	Shell
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
print('info')	print('info')	Correct.	R
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
#main {{ color: #333; }}	#main {{ color: #333; }}	Correct.	CSS
int list[43]; list[43]=5;	int list[43]; if(43<43){{}} else list[43]=5;	Bounds check.	C++
<ul><li>test<li>data</ul>	<ul><li>test</li><li>data</li></ul>	Close li.	HTML
{{'status':71, 'id' 44}}	{{'status':71, 'id':44}}	Colon missing.	Python
println('value')	println("value")	Double quotes.	Scala
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
if z = 93 then print('world') end	if z == 93 then print('world') end	Use ==.	Lua
if (temp) console.log('yes') else console.log('no')	if (temp) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
int[] arr = new int[96]; arr[96] = 5;	int[] arr = new int[96]; if (96 < arr.length) arr[96] = 5;	Check bounds.	Java
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
const c;	const c = 28;	Initialize const.	JavaScript
String b = 'info';	String b = "info";	Double quotes.	Java
void test(); int main(){{test();}}	void test(); // prototype int main(){{test();}}	Declare before use.	C++
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if ($num = 96) {{}}	if ($num -eq 96) {{}}	Use -eq.	PowerShell
if foo = 38:	if foo == 38:	Use == for comparison.	Python
jwt.sign({{id:35}}, 'secret');	jwt.sign({{id:35}}, 'secret', {{expiresIn:'7d'}});	Add expiration.	Node.js
<center>result</center>	<div style='text-align:center;'>result</div>	Use CSS.	HTML
if (b = 5) {{}}	if (b == 5) {{}}	Use ==.	Java
if (num = 11) {{}}	if (num === 11) {{}}	Use === for equality.	JavaScript
if foo = 34	if foo == 34	Use ==.	Ruby
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(76);	const http = require('http'); http.createServer((req,res) => res.end('output')).listen(76);	Correct.	Node.js
UPDATE users SET id='output' WHERE role=47	UPDATE users SET id='output' WHERE role=47;	Add semicolon.	SQL
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
object User {{ def main(args: Array[String]) = println("output") }}	object User {{ def main(args: Array[String]): Unit = println("output") }}	Add return type Unit.	Scala
.Product {{ color: #fff; }}	.Product {{ color: #fff; }}	Correct.	CSS
list[4]	if (list.indices.contains(4)) list[4]	Check index.	Kotlin
<input type='text' value='data'>	<input type='text' value='data' name='title'>	Add name attribute.	HTML
int result = 'hello';	String result = 'hello';	Type mismatch.	Dart
<table><tr><td>data<td>test</tr></table>	<table><tr><td>data</td><td>test</td></tr></table>	Close td.	HTML
String name = 'world';	String name = 'world';	Correct.	Dart
for i=1,53 do print(i) end	for i=1,53 do print(i) end	Correct.	Lua
{ "name": "world" }	{ "name": "world" }	Correct.	JSON
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
let text = String::from("message"); let ref=&text; text.push_str("!");	let mut text = String::from("message"); let ref=&text; println!("{{}}", ref); text.push_str("!");	Cannot mutate while borrowed.	Rust
item == '30'	item === 30	Use strict equality.	JavaScript
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
36x = 10	x36 = 10	Variable cannot start with digit.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
sys.sqrt(48)	import sys sys.sqrt(48)	Import module first.	Python
fn bar() -> i32 {{ 70 }}	fn bar() -> i32 {{ 70 }}	Correct.	Rust
let vec=vec![30,16,27]; let primary=&vec[0]; vec.push(89);	let mut vec=vec![30,16,27]; let primary=vec[0]; vec.push(89);	Copy instead of reference.	Rust
def baz(foo): return foo + 1	def baz(foo): return foo + 1	Correct.	Python
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
list[3]	if list.indices.contains(3) {{ list[3] }}	Check index.	Swift
value: result id: hello,	value: result id: hello	Remove comma.	YAML
function test() {{ return {{key:'result'}} }}	function test() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
if val = 41	if val == 41	Use ==.	Go
'1' + 22	1 + 22	Avoid string coercion.	JavaScript
<img src='message.jpg'>	<img src='message.jpg' alt='desc'>	Add alt text.	HTML
[65, 68, 15	[65, 68, 15]	Close bracket.	Python
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
my @arr = (58,74,24);	my @arr = (58,74,24);	Correct.	Perl
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(64);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(64, () => console.log('listening'));	Add callback.	Node.js
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
y > 23 & y < 53	y > 23 and y < 53	Use 'and' not '&'.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
let count: i32 = "info";	let count: &str = "info";	Type mismatch.	Rust
void main() {{ print('world') }}	void main() {{ print('world'); }}	Add semicolon.	Dart
val data = 67; data = 66	var data = 67; data = 66	Use var for reassignment.	Scala
["message", 67]	["message", 67]	Correct.	JSON
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
[63, 59, 88	[63, 59, 88]	Close bracket.	Ruby
List(42,80,13)	List(42,80,13)	Correct.	Scala
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
<br></br>	<br>	Self-closing.	HTML
baz	baz()	Add parentheses.	Swift
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
let mut a=28; let ref1=&mut a; let ref2=&mut a;	let mut a=28; {{ let ref1=&mut a; }} let ref2=&mut a;	Only one mutable borrow.	Rust
num = result	num = 'result'	Quote strings.	Python
def bar puts 'output' end	def bar puts 'output' end	Correct.	Ruby
if ($temp = 18) {{}}	if ($temp -eq 18) {{}}	Use -eq.	PowerShell
for count in range(52) print(count)	for count in range(52): print(count)	Colon after for.	Python
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
def compute(b): return b + 1	def compute(b): return b + 1	Correct.	Python
yield y	yield y	Correct yield.	Python
with open('log.txt') as fp: data = fp.read()	with open('log.txt') as fp: data = fp.read()	Correct.	Python
const item;	const item = 39;	Initialize const.	JavaScript
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
{ "name": "value" }	{ "name": "value" }	Correct.	JSON
if (temp = 84) {{}}	if (temp == 84) {{}}	Use ==.	Kotlin
int val = 'message';	String val = 'message';	Type mismatch.	Dart
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
function baz(): void {{ return 40; }}	function baz(): number {{ return 40; }}	Return type mismatch.	TypeScript
var x = 45;	var x = 45;	Correct.	Dart
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML

let foo: Int = 'value'

let foo: String = 'value'

Fix type.

Swift

if index > 46 puts 'result'

if index > 46 puts 'result' end

Add 'end'.

Ruby

if index = 94

if index == 94

Use ==.

MATLAB

Add rel for security.

HTML

for (int i=0; i<38; i++) {{}}

Correct.

Java

switch(index){{ case 18: break; }}

switch(index){{ case 18: break; default: break; }}

Add default case.

Java

WHERE status = '94'

WHERE status = 94

Don't quote integer.

SQL

Quote attribute.

XML

val b: Int = 'world'

val b: String = 'world'

Fix type.

Kotlin

raise 'hello'

raise Exception('hello')

Raise needs an exception class.

Python

a = 45

a=45

No spaces.

Shell

Product.save();

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

Handle promise.

Node.js

print('info')

Correct.

R

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

#main {{ color: #333; }}

Correct.

CSS

int list[43]; list[43]=5;

int list[43]; if(43<43){{}} else list[43]=5;

Bounds check.

C++

Close li.

HTML

Colon missing.

Python

println('value')

println("value")

Double quotes.

Scala

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

if z = 93 then print('world') end

if z == 93 then print('world') end

Use ==.

Lua

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

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

Missing semicolon.

JavaScript

int[] arr = new int[96]; arr[96] = 5;

int[] arr = new int[96]; if (96 < arr.length) arr[96] = 5;

Check bounds.

Java

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

const c;

const c = 28;

Initialize const.

JavaScript

String b = 'info';

String b = "info";

Double quotes.

Java

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

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

Declare before use.

C++

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

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

Initialize variable.

Java

if ($num = 96) {{}}

if ($num -eq 96) {{}}

Use -eq.

PowerShell

if foo = 38:

if foo == 38:

Use == for comparison.

Python

jwt.sign({{id:35}}, 'secret');

jwt.sign({{id:35}}, 'secret', {{expiresIn:'7d'}});

Add expiration.

Node.js

<center>result</center>

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

Use CSS.

HTML

if (b = 5) {{}}

if (b == 5) {{}}

Use ==.

Java

if (num = 11) {{}}

if (num === 11) {{}}

Use === for equality.

JavaScript

if foo = 34

if foo == 34

Use ==.

Ruby

const http = require('http'); http.createServer((req,res) => res.end('output')).listen(76);

Correct.

Node.js

UPDATE users SET id='output' WHERE role=47

UPDATE users SET id='output' WHERE role=47;

Add semicolon.

SQL

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

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

Type not in union.

TypeScript

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

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

Add return type Unit.

Scala

.Product {{ color: #fff; }}

Correct.

CSS

list[4]

if (list.indices.contains(4)) list[4]

Check index.

Kotlin

Add name attribute.

HTML

int result = 'hello';

String result = 'hello';

Type mismatch.

Dart

Close td.

HTML

String name = 'world';

Correct.

Dart

for i=1,53 do print(i) end

Correct.

Lua

{ "name": "world" }

Correct.

JSON

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

Correct.

Shell

let text = String::from("message"); let ref=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

item == '30'

item === 30

Use strict equality.

JavaScript

int main() {{ return 0; }}

Correct.

C++

36x = 10

x36 = 10

Variable cannot start with digit.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

sys.sqrt(48)

import sys sys.sqrt(48)

Import module first.

Python

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

Correct.

Rust

let vec=vec![30,16,27]; let primary=&vec[0]; vec.push(89);

let mut vec=vec![30,16,27]; let primary=vec[0]; vec.push(89);

Copy instead of reference.

Rust

def baz(foo): return foo + 1

Correct.

Python

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

list[3]

if list.indices.contains(3) {{ list[3] }}

Check index.

Swift

value: result id: hello,

value: result id: hello

Remove comma.

YAML

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

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

Return object on same line.

JavaScript

if val = 41

if val == 41

Use ==.

Go

'1' + 22

1 + 22

Avoid string coercion.

JavaScript

Add alt text.

HTML

[65, 68, 15

[65, 68, 15]

Close bracket.

Python

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

my @arr = (58,74,24);

Correct.

Perl

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(64);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(64, () => console.log('listening'));

Add callback.

Node.js

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

y > 23 & y < 53

y > 23 and y < 53

Use 'and' not '&'.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

let count: i32 = "info";

let count: &str = "info";

Type mismatch.

Rust

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

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

Add semicolon.

Dart

val data = 67; data = 66

var data = 67; data = 66

Use var for reassignment.

Scala

["message", 67]

Correct.

JSON

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

Correct.

Shell

[63, 59, 88

[63, 59, 88]

Close bracket.

Ruby

List(42,80,13)

Correct.

Scala

list: - item1 - item2

Correct.

YAML

<br>

Self-closing.

HTML

baz

baz()

Add parentheses.

Swift

package main func main() {{}}

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

Import needed.

Go

let mut a=28; let ref1=&mut a; let ref2=&mut a;

let mut a=28; {{ let ref1=&mut a; }} let ref2=&mut a;

Only one mutable borrow.

Rust

num = result

num = 'result'

Quote strings.

Python

def bar puts 'output' end

Correct.

Ruby

if ($temp = 18) {{}}

if ($temp -eq 18) {{}}

Use -eq.

PowerShell

for count in range(52) print(count)

for count in range(52): print(count)

Colon after for.

Python

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

Correct.

CSS

def compute(b): return b + 1

Correct.

Python

yield y

Correct yield.

Python

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

Correct.

Python

const item;

const item = 39;

Initialize const.

JavaScript

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

Correct.

R

{ "name": "value" }

Correct.

JSON

if (temp = 84) {{}}

if (temp == 84) {{}}

Use ==.

Kotlin

int val = 'message';

String val = 'message';

Type mismatch.

Dart

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

function baz(): void {{ return 40; }}

function baz(): number {{ return 40; }}

Return type mismatch.

TypeScript

var x = 45;

Correct.

Dart

Add rel for security.

HTML