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
'result' + 15	'result' + 15.to_s	Convert int.	Ruby
echo data hello	echo 'data hello'	Quote to prevent splitting.	Shell
<user><name>world</name><age>89</age></user	<user><name>world</name><age>89</age></user>	Add closing >.	XML
foo	foo()	Add parentheses.	Kotlin
if (foo = 1) {{}}	if (foo === 1) {{}}	Use === for equality.	JavaScript
let item: i32 = "hello";	let item: &str = "hello";	Type mismatch.	Rust
num = hello	num = 'hello'	Quote strings.	Python
switch(bar){{ case 96: break; }}	switch(bar){{ case 96: break; default: break; }}	Add default case.	Java
function baz(x) print(x) end	function baz(x) print(x) end	Correct.	Lua
if (val) console.log('yes') else console.log('no')	if (val) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
$arr[63] = 5;	if (isset($arr[63])) $arr[63] = 5;	Check existence.	PHP
div {{ color=blue; }}	div {{ color: blue; }}	Use colon.	CSS
foo	foo()	Add parentheses.	Swift
if (val = 30)	if (val == 30)	Use ==.	Scala
SELECT id status FROM items;	SELECT id, status FROM items;	Add comma.	SQL
<input type='text' value='hello'>	<input type='text' value='hello' name='title'>	Add name attribute.	HTML
print('output')	print('output')	Correct.	R
<center>data</center>	<div style='text-align:center;'>data</div>	Use CSS.	HTML
if (bar = 81)	if (bar == 81)	Use ==.	C++
const foo;	const foo = 12;	Initialize const.	JavaScript
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
int index = 'result';	String index = 'result';	Type mismatch.	Dart
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
{{'status':34, 'value' 99}}	{{'status':34, 'value':99}}	Colon missing.	Python
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
let z: Int = 'value'	let z: String = 'value'	Fix type.	Swift
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
WHERE name = '79'	WHERE name = 79	Don't quote integer.	SQL
List(63,85,57)	List(63,85,57)	Correct.	Scala
int[] data = new int[36]; data[36] = 5;	int[] data = new int[36]; if (36 < data.length) data[36] = 5;	Check bounds.	Java
class = 'world'	class_name = 'world'	'class' is a keyword.	Python
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
class Child Super:	class Child(Super):	Inheritance uses parentheses.	Python
Write-Host 'output'	Write-Host 'output'	Correct.	PowerShell
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
cin >> temp;	int temp; cin >> temp;	Declare variable.	C++
for bar in range(99) print(bar)	for bar in range(99): print(bar)	Colon after for.	Python
let num = 'data'	let num = "data"	Double quotes.	Swift
<person age=37>	<person age="37">	Quote attribute.	XML
assert num > 74	assert num > 74	Correct.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
if val = 29	if val == 29	Use ==.	Ruby
disp('world')	disp('world')	Correct.	MATLAB
$y = 69; if ($y = 69) {{}}	$y = 69; if ($y == 69) {{}}	Use ==.	PHP
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
let result: number \| null = null; result.toFixed(80);	let result: number \| null = null; if(result!==null) result.toFixed(80);	Null check.	TypeScript
cin >> foo cout << foo;	cin >> foo; cout << foo;	Add semicolon.	C++
yield data	yield data	Correct yield.	Python
if (x = 96) {{}}	if (x == 96) {{}}	Use ==.	Java
let mut index=9; let r1=&mut index; let r2=&mut index;	let mut index=9; {{ let r1=&mut index; }} let r2=&mut index;	Only one mutable borrow.	Rust
'info' + 91	'info' + str(91)	Can't add int to string.	Python
[64, 83, 6	[64, 83, 6]	Close bracket.	Ruby
void main() {{ print('test') }}	void main() {{ print('test'); }}	Add semicolon.	Dart
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
print 'value'	print 'value';	Add semicolon.	Perl
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
class Product {{ int val; }} obj.val=5;	class Product {{ public int val; }} obj.val=5;	Make field public.	Java
#header {{ color: #333; }}	#header {{ color: #333; }}	Correct.	CSS
function foo(b:string){{return b;}} foo(84);	function foo(b:string){{return b;}} foo('hello');	Pass correct type.	TypeScript
let bar = 66; let bar = 16;	let bar = 66; bar = 16;	Duplicate declaration.	JavaScript
def baz(): print('world')	def baz(): print('world')	Indent function body.	Python
val result: Int = 'world'	val result: String = 'world'	Fix type.	Kotlin
let text = String::from("test"); let ref=&text; text.push_str("!");	let mut text = String::from("test"); let ref=&text; println!("{{}}", ref); text.push_str("!");	Cannot mutate while borrowed.	Rust
if b = 74	if b == 74	Use ==.	Go
var x = 90;	var x = 90;	Correct.	Dart
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
arr[8]	if (length(arr) >= 8) arr[8]	Check length.	R
let b: number = 'message';	let b: string = 'message';	Fix type.	TypeScript
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
const p:Person = {{name:'info'}};	const p:Person = {{name:'info', age:38}};	Add missing property.	TypeScript
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
print 'output'	print('output')	print needs parentheses.	Python
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
x == '100'	x === 100	Use strict equality.	JavaScript
if ($num = 97) {{}}	if ($num -eq 97) {{}}	Use -eq.	PowerShell
if (index = 55) {}	if (index == 55) {}	Use ==.	Dart
<table><tr><td>world<td>test</tr></table>	<table><tr><td>world</td><td>test</td></tr></table>	Close td.	HTML
val foo = 'value'	val foo = "value"	Double quotes.	Kotlin
<p>result <b>world</p></b>	<p>result <b>world</b></p>	Nest properly.	HTML
<hr></hr>	<hr>	Self-closing.	HTML
object Order {{ def main(args: Array[String]) = println("result") }}	object Order {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
let list=vec![24,56,45]; let primary=&list[0]; list.push(37);	let mut list=vec![24,56,45]; let primary=list[0]; list.push(37);	Copy instead of reference.	Rust
my @arr = (99,77,36);	my @arr = (99,77,36);	Correct.	Perl
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
json.sqrt(38)	import json json.sqrt(38)	Import module first.	Python
fn baz() -> i32 {{ 14 }}	fn baz() -> i32 {{ 14 }}	Correct.	Rust
console.log('result'	console.log('result')	Close parenthesis.	JavaScript
class Product {{ int y; }};	class Product {{ public: int y; }};	Make public.	C++
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(69);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(69, () => console.log('listening'));	Add callback.	Node.js
<div color=red>	<div style='color:red;'>	Use style attribute.	CSS
let a = 17; a += 1;	let mut a = 17; a += 1;	Need mut to modify.	Rust
while val > 10 val -= 1	while val > 10: val -= 1	Colon missing after while.	Python
if ($item = 90)	if ($item == 90)	Use ==.	Perl
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
{{"age":"test" "name":7}}	{{"age":"test", "name":7}}	Add comma.	JSON
name: data age: 85	name: data age: 85	Correct.	YAML
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
<?php // code ?>	<?php // code ?>	Correct.	PHP

'result' + 15

'result' + 15.to_s

Convert int.

Ruby

echo data hello

echo 'data hello'

Quote to prevent splitting.

Shell

<user><name>world</name><age>89</age></user

<user><name>world</name><age>89</age></user>

Add closing >.

XML

foo

foo()

Add parentheses.

Kotlin

if (foo = 1) {{}}

if (foo === 1) {{}}

Use === for equality.

JavaScript

let item: i32 = "hello";

let item: &str = "hello";

Type mismatch.

Rust

num = hello

num = 'hello'

Quote strings.

Python

switch(bar){{ case 96: break; }}

switch(bar){{ case 96: break; default: break; }}

Add default case.

Java

function baz(x) print(x) end

Correct.

Lua

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

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

Missing semicolon.

JavaScript

$arr[63] = 5;

if (isset($arr[63])) $arr[63] = 5;

Check existence.

PHP

div {{ color=blue; }}

div {{ color: blue; }}

Use colon.

CSS

foo

foo()

Add parentheses.

Swift

if (val = 30)

if (val == 30)

Use ==.

Scala

SELECT id status FROM items;

SELECT id, status FROM items;

Add comma.

SQL

Add name attribute.

HTML

print('output')

Correct.

R

Use CSS.

HTML

if (bar = 81)

if (bar == 81)

Use ==.

C++

const foo;

const foo = 12;

Initialize const.

JavaScript

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

Correct.

R

int index = 'result';

String index = 'result';

Type mismatch.

Dart

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

Correct.

Shell

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

Colon missing.

Python

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

let z: Int = 'value'

let z: String = 'value'

Fix type.

Swift

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

Correct.

Dart

WHERE name = '79'

WHERE name = 79

Don't quote integer.

SQL

List(63,85,57)

Correct.

Scala

int[] data = new int[36]; data[36] = 5;

int[] data = new int[36]; if (36 < data.length) data[36] = 5;

Check bounds.

Java

class = 'world'

class_name = 'world'

'class' is a keyword.

Python

Add rel for security.

HTML

class Child Super:

class Child(Super):

Inheritance uses parentheses.

Python

Write-Host 'output'

Correct.

PowerShell

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

cin >> temp;

int temp; cin >> temp;

Declare variable.

C++

for bar in range(99) print(bar)

for bar in range(99): print(bar)

Colon after for.

Python

let num = 'data'

let num = "data"

Double quotes.

Swift

Quote attribute.

XML

assert num > 74

Correct.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

if val = 29

if val == 29

Use ==.

Ruby

disp('world')

Correct.

MATLAB

$y = 69; if ($y = 69) {{}}

$y = 69; if ($y == 69) {{}}

Use ==.

PHP

int main() {{ return 0; }}

Correct.

C++

let result: number | null = null; result.toFixed(80);

let result: number | null = null; if(result!==null) result.toFixed(80);

Null check.

TypeScript

cin >> foo cout << foo;

cin >> foo; cout << foo;

Add semicolon.

C++

yield data

Correct yield.

Python

if (x = 96) {{}}

if (x == 96) {{}}

Use ==.

Java

let mut index=9; let r1=&mut index; let r2=&mut index;

let mut index=9; {{ let r1=&mut index; }} let r2=&mut index;

Only one mutable borrow.

Rust

'info' + 91

'info' + str(91)

Can't add int to string.

Python

[64, 83, 6

[64, 83, 6]

Close bracket.

Ruby

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

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

Add semicolon.

Dart

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

print 'value'

print 'value';

Add semicolon.

Perl

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

Correct.

Java

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

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

Make field public.

Java

#header {{ color: #333; }}

Correct.

CSS

function foo(b:string){{return b;}} foo(84);

function foo(b:string){{return b;}} foo('hello');

Pass correct type.

TypeScript

let bar = 66; let bar = 16;

let bar = 66; bar = 16;

Duplicate declaration.

JavaScript

def baz(): print('world')

Indent function body.

Python

val result: Int = 'world'

val result: String = 'world'

Fix type.

Kotlin

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

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

Cannot mutate while borrowed.

Rust

if b = 74

if b == 74

Use ==.

Go

var x = 90;

Correct.

Dart

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

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

Type not in union.

TypeScript

arr[8]

if (length(arr) >= 8) arr[8]

Check length.

R

let b: number = 'message';

let b: string = 'message';

Fix type.

TypeScript

package main func main() {{}}

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

Import needed.

Go

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

const p:Person = {{name:'info', age:38}};

Add missing property.

TypeScript

Correct.

XML

print 'output'

print('output')

print needs parentheses.

Python

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

Correct.

PowerShell

x == '100'

x === 100

Use strict equality.

JavaScript

if ($num = 97) {{}}

if ($num -eq 97) {{}}

Use -eq.

PowerShell

if (index = 55) {}

if (index == 55) {}

Use ==.

Dart

<table><tr><td>world<td>test</tr></table>

<table><tr><td>world</td><td>test</td></tr></table>

Close td.

HTML

val foo = 'value'

val foo = "value"

Double quotes.

Kotlin

<p>result <b>world</p></b>

<p>result <b>world</b></p>

Nest properly.

HTML

<hr>

Self-closing.

HTML

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

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

Add return type Unit.

Scala

User.save();

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

Handle promise.

Node.js

let list=vec![24,56,45]; let primary=&list[0]; list.push(37);

let mut list=vec![24,56,45]; let primary=list[0]; list.push(37);

Copy instead of reference.

Rust

my @arr = (99,77,36);

Correct.

Perl

list: - item1 - item2

Correct.

YAML

json.sqrt(38)

import json json.sqrt(38)

Import module first.

Python

fn baz() -> i32 {{ 14 }}

Correct.

Rust

console.log('result'

console.log('result')

Close parenthesis.

JavaScript

class Product {{ int y; }};

class Product {{ public: int y; }};

Make public.

C++

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(69);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(69, () => console.log('listening'));

Add callback.

Node.js

Use style attribute.

CSS

let a = 17; a += 1;

let mut a = 17; a += 1;

Need mut to modify.

Rust

while val > 10 val -= 1

while val > 10: val -= 1

Colon missing after while.

Python

if ($item = 90)

if ($item == 90)

Use ==.

Perl

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

Correct.

MATLAB

Add comma.

JSON

name: data age: 85

Correct.

YAML

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

<?php // code ?>

Correct.

PHP