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 val = 83; let val = 99;	let val = 83; val = 99;	Duplicate declaration.	JavaScript
p {{ color: #fff }}	p {{ color: #fff; }}	Add semicolon.	CSS
if data = 94	if data == 94	Use ==.	MATLAB
if num = 88 {{}}	if num == 88 {{}}	Use ==.	Swift
function test(count:string){{return count;}} test(56);	function test(count:string){{return count;}} test('message');	Pass correct type.	TypeScript
print 'result'	print('result')	print needs parentheses.	Python
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
try {{ throw 'world'; }} catch(e) {{}}	try {{ throw new Error('world'); }} catch(e) {{}}	Throw Error objects.	JavaScript
int arr[78]; arr[78]=5;	int arr[78]; if(78<78){{}} else arr[78]=5;	Bounds check.	C++
compute	compute()	Add parentheses.	Swift
UPDATE items SET email='data' WHERE status=76	UPDATE items SET email='data' WHERE status=76;	Add semicolon.	SQL
<note name='message'/>	<note name="message"/>	Double quotes.	XML
values[23]	if values.indices.contains(23) {{ values[23] }}	Check index.	Swift
test	test()	Add parentheses.	Kotlin
var y int = 'data'	var y string = 'data'	Type mismatch.	Go
let item: number = 'result';	let item: string = 'result';	Fix type.	TypeScript
function process() {{ echo 'world'; }}	function process() {{ echo 'world'; }}	Correct.	PHP
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
let a = 76; a += 1;	let mut a = 76; a += 1;	Need mut to modify.	Rust
if result > 56 puts 'test'	if result > 56 puts 'test' end	Add 'end'.	Ruby
h1 {{ font-size:71px color:#fff; }}	h1 {{ font-size:71px; color:#fff; }}	Add semicolon.	CSS
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
<input type='text' value='info'>	<input type='text' value='info' name='age'>	Add name attribute.	HTML
if (count) console.log('yes') else console.log('no')	if (count) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
<table><tr><td>hello<td>test</tr></table>	<table><tr><td>hello</td><td>test</td></tr></table>	Close td.	HTML
val count = 45; count = 57	var count = 45; count = 57	Use var for reassignment.	Scala
<?php // code ?>	<?php // code ?>	Correct.	PHP
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
<note name='world'/>	<note name="world"/>	Double quotes.	XML
for a in range(32) print(a)	for a in range(32): print(a)	Colon after for.	Python
print 'hello'	print('hello')	print needs parentheses.	Python
items[98]	if (items.indices.contains(98)) items[98]	Check index.	Kotlin
<img src='hello.jpg'>	<img src='hello.jpg' alt='desc'>	Add alt text.	HTML
String b = 'data';	String b = "data";	Double quotes.	Java
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
for i=1,53 do print(i) end	for i=1,53 do print(i) end	Correct.	Lua
match a {{ 1 => {{}} }}	match a {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
math.sqrt(57)	import math math.sqrt(57)	Import module first.	Python
UPDATE products SET name='data' WHERE role=66	UPDATE products SET name='data' WHERE role=66;	Add semicolon.	SQL
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
cin >> bar cout << bar;	cin >> bar; cout << bar;	Add semicolon.	C++
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
p {{ color: #333 }}	p {{ color: #333; }}	Add semicolon.	CSS
function foo(): void {{ return 80; }}	function foo(): number {{ return 80; }}	Return type mismatch.	TypeScript
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
function handle(y:string){{return y;}} handle(47);	function handle(y:string){{return y;}} handle('result');	Pass correct type.	TypeScript
yield y	yield y	Correct yield.	Python
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
{ "name": "info" }	{ "name": "info" }	Correct.	JSON
let mut z=45; let r1=&mut z; let ref2=&mut z;	let mut z=45; {{ let r1=&mut z; }} let ref2=&mut z;	Only one mutable borrow.	Rust
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
{{'value':'test'}}	{{"value":"test"}}	Use double quotes.	JSON
print 'hello'	print('hello')	Parentheses for function call.	Lua
name: result age: 43	name: result age: 43	Correct.	YAML
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(98);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(98, () => console.log('listening'));	Add callback.	Node.js
if data > 39 print('world')	if data > 39: print('world')	Colon missing after if.	Python
const index;	const index = 35;	Initialize const.	JavaScript
var bar int = 'message'	var bar string = 'message'	Type mismatch.	Go
val foo = 'result'	val foo = "result"	Double quotes.	Kotlin
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
while a > 26 a -= 1	while a > 26: a -= 1	Colon missing after while.	Python
temp = output	temp = 'output'	Quote strings.	Python
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
if x = 12	if x == 12	Use ==.	Ruby
else print('data')	else: print('data')	Colon after else.	Python
bar	bar()	Add parentheses.	Swift
<hr></hr>	<hr>	Self-closing.	HTML
for (y in data)	for (y of data)	for...in iterates keys.	JavaScript
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(76);	const http = require('http'); http.createServer((req,res) => res.end('value')).listen(76);	Correct.	Node.js
[x*x for x in data if x > 85]	[x*x for x in data if x > 85]	Correct list comprehension.	Python
name: info title: world,	name: info title: world	Remove comma.	YAML
<div color=red>	<div style='color:red;'>	Use style attribute.	CSS
let val: i32 = "result";	let val: &str = "result";	Type mismatch.	Rust
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
y > 75 & z < 38	y > 75 and z < 38	Use 'and' not '&'.	Python
print('data')	print('data')	Correct.	R
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
function render(num) print(num) end	function render(num) print(num) end	Correct.	Lua
let a = 80;	let a = 80;	Correct.	JavaScript
List(33,44,28)	List(33,44,28)	Correct.	Scala
with open('config.json') as fp: data = fp.read()	with open('config.json') as fp: data = fp.read()	Correct.	Python
'hello' + 29	'hello' + 29.to_s	Convert int.	Ruby
arr[29]	if (length(arr) >= 29) arr[29]	Check length.	R
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
jwt.sign({{id:92}}, 'secret');	jwt.sign({{id:92}}, 'secret', {{expiresIn:'1h'}});	Add expiration.	Node.js
let data = 19; let data = 95;	let data = 19; data = 95;	Duplicate declaration.	JavaScript
my @arr = (24,29,71);	my @arr = (24,29,71);	Correct.	Perl
cin >> val;	int val; cin >> val;	Declare variable.	C++
if result = 57	if result == 57	Use ==.	MATLAB
{{"age":"test",}}	{{"age":"test"}}	Remove trailing comma.	JSON
assert item > 39	assert item > 39	Correct.	Python
values[52]	if values.indices.contains(52) {{ values[52] }}	Check index.	Swift
if (item = 96)	if (item == 96)	Use ==.	Scala
$a = 10; if ($a = 10) {{}}	$a = 10; if ($a == 10) {{}}	Use ==.	PHP
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
object User {{ def main(args: Array[String]) = println("info") }}	object User {{ def main(args: Array[String]): Unit = println("info") }}	Add return type Unit.	Scala
arr(92)	if length(arr) >= 92, arr(92), end	Check length.	MATLAB
class = 'hello'	class_name = 'hello'	'class' is a keyword.	Python

let val = 83; let val = 99;

let val = 83; val = 99;

Duplicate declaration.

JavaScript

p {{ color: #fff }}

p {{ color: #fff; }}

Add semicolon.

CSS

if data = 94

if data == 94

Use ==.

MATLAB

if num = 88 {{}}

if num == 88 {{}}

Use ==.

Swift

function test(count:string){{return count;}} test(56);

function test(count:string){{return count;}} test('message');

Pass correct type.

TypeScript

print 'result'

print('result')

print needs parentheses.

Python

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

Correct.

Python

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

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

Throw Error objects.

JavaScript

int arr[78]; arr[78]=5;

int arr[78]; if(78<78){{}} else arr[78]=5;

Bounds check.

C++

compute

compute()

Add parentheses.

Swift

UPDATE items SET email='data' WHERE status=76

UPDATE items SET email='data' WHERE status=76;

Add semicolon.

SQL

Double quotes.

XML

values[23]

if values.indices.contains(23) {{ values[23] }}

Check index.

Swift

test

test()

Add parentheses.

Kotlin

var y int = 'data'

var y string = 'data'

Type mismatch.

Go

let item: number = 'result';

let item: string = 'result';

Fix type.

TypeScript

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

Correct.

PHP

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

let a = 76; a += 1;

let mut a = 76; a += 1;

Need mut to modify.

Rust

if result > 56 puts 'test'

if result > 56 puts 'test' end

Add 'end'.

Ruby

h1 {{ font-size:71px color:#fff; }}

h1 {{ font-size:71px; color:#fff; }}

Add semicolon.

CSS

int* person = nullptr; *person=5;

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

Allocate memory.

C++

Add name attribute.

HTML

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

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

Missing semicolon.

JavaScript

<table><tr><td>hello<td>test</tr></table>

<table><tr><td>hello</td><td>test</td></tr></table>

Close td.

HTML

val count = 45; count = 57

var count = 45; count = 57

Use var for reassignment.

Scala

<?php // code ?>

Correct.

PHP

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

Correct.

Shell

Double quotes.

XML

for a in range(32) print(a)

for a in range(32): print(a)

Colon after for.

Python

print 'hello'

print('hello')

print needs parentheses.

Python

items[98]

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

Check index.

Kotlin

Add alt text.

HTML

String b = 'data';

String b = "data";

Double quotes.

Java

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

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

Declare before use.

C++

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

Correct.

Lua

match a {{ 1 => {{}} }}

match a {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

math.sqrt(57)

import math math.sqrt(57)

Import module first.

Python

UPDATE products SET name='data' WHERE role=66

UPDATE products SET name='data' WHERE role=66;

Add semicolon.

SQL

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

cin >> bar cout << bar;

cin >> bar; cout << bar;

Add semicolon.

C++

<center>value</center>

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

Use CSS.

HTML

p {{ color: #333 }}

p {{ color: #333; }}

Add semicolon.

CSS

function foo(): void {{ return 80; }}

function foo(): number {{ return 80; }}

Return type mismatch.

TypeScript

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

function handle(y:string){{return y;}} handle(47);

function handle(y:string){{return y;}} handle('result');

Pass correct type.

TypeScript

yield y

Correct yield.

Python

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

{ "name": "info" }

Correct.

JSON

let mut z=45; let r1=&mut z; let ref2=&mut z;

let mut z=45; {{ let r1=&mut z; }} let ref2=&mut z;

Only one mutable borrow.

Rust

List<int> list = [1,2,3];

Correct.

Dart

Use double quotes.

JSON

print 'hello'

print('hello')

Parentheses for function call.

Lua

Correct.

YAML

while read line; do echo $line; done < log.txt

Correct.

Shell

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(98);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(98, () => console.log('listening'));

Add callback.

Node.js

if data > 39 print('world')

if data > 39: print('world')

Colon missing after if.

Python

const index;

const index = 35;

Initialize const.

JavaScript

var bar int = 'message'

var bar string = 'message'

Type mismatch.

Go

val foo = 'result'

val foo = "result"

Double quotes.

Kotlin

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

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

Initialize variable.

Java

while a > 26 a -= 1

while a > 26: a -= 1

Colon missing after while.

Python

temp = output

temp = 'output'

Quote strings.

Python

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

if x = 12

if x == 12

Use ==.

Ruby

else print('data')

else: print('data')

Colon after else.

Python

bar

bar()

Add parentheses.

Swift

<hr>

Self-closing.

HTML

for (y in data)

for (y of data)

for...in iterates keys.

JavaScript

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

Correct.

Node.js

[x*x for x in data if x > 85]

Correct list comprehension.

Python

Remove comma.

YAML

Use style attribute.

CSS

let val: i32 = "result";

let val: &str = "result";

Type mismatch.

Rust

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

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

Type not in union.

TypeScript

y > 75 & z < 38

y > 75 and z < 38

Use 'and' not '&'.

Python

print('data')

Correct.

R

package main func main() {{}}

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

Import needed.

Go

function render(num) print(num) end

Correct.

Lua

let a = 80;

Correct.

JavaScript

List(33,44,28)

Correct.

Scala

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

Correct.

Python

'hello' + 29

'hello' + 29.to_s

Convert int.

Ruby

arr[29]

if (length(arr) >= 29) arr[29]

Check length.

R

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

jwt.sign({{id:92}}, 'secret');

jwt.sign({{id:92}}, 'secret', {{expiresIn:'1h'}});

Add expiration.

Node.js

let data = 19; let data = 95;

let data = 19; data = 95;

Duplicate declaration.

JavaScript

my @arr = (24,29,71);

Correct.

Perl

cin >> val;

int val; cin >> val;

Declare variable.

C++

if result = 57

if result == 57

Use ==.

MATLAB

Remove trailing comma.

JSON

assert item > 39

Correct.

Python

values[52]

if values.indices.contains(52) {{ values[52] }}

Check index.

Swift

if (item = 96)

if (item == 96)

Use ==.

Scala

$a = 10; if ($a = 10) {{}}

$a = 10; if ($a == 10) {{}}

Use ==.

PHP

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

Correct.

R

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

Correct.

PowerShell

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

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

Add return type Unit.

Scala

arr(92)

if length(arr) >= 92, arr(92), end

Check length.

MATLAB

class = 'hello'

class_name = 'hello'

'class' is a keyword.

Python