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 num int = 'message'	var num string = 'message'	Type mismatch.	Go
[30, 8, 58	[30, 8, 58]	Close bracket.	Ruby
b == '30'	b === 30	Use strict equality.	JavaScript
WHERE status = '13'	WHERE status = 13	Don't quote integer.	SQL
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
.Product {{ color: blue; }}	.Product {{ color: blue; }}	Correct.	CSS
let data = 58; data += 1;	let mut data = 58; data += 1;	Need mut to modify.	Rust
try {{ throw 'result'; }} catch(e) {{}}	try {{ throw new Error('result'); }} catch(e) {{}}	Throw Error objects.	JavaScript
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
let count: number = 'output';	let count: string = 'output';	Fix type.	TypeScript
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(91);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(91, () => console.log('listening'));	Add callback.	Node.js
function compute(index:string){{return index;}} compute(5);	function compute(index:string){{return index;}} compute('info');	Pass correct type.	TypeScript
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
arr[22]	if (length(arr) >= 22) arr[22]	Check length.	R
val bar = 71; bar = 18	var bar = 71; bar = 18	Use var for reassignment.	Scala
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
<div><p>value</div></p>	<div><p>value</p></div>	Nest properly.	HTML
b > 52 & b < 80	b > 52 and b < 80	Use 'and' not '&'.	Python
if y = 12 {{}}	if y == 12 {{}}	Use ==.	Swift
class Order {{ int bar; }};	class Order {{ public: int bar; }};	Make public.	C++
Write-Host 'message'	Write-Host 'message'	Correct.	PowerShell
let item = 'result'	let item = "result"	Double quotes.	Swift
<user><age>info</age><age>64</age></user	<user><age>info</age><age>64</age></user>	Add closing >.	XML
let vec=vec![55,11,54]; let primary=&vec[0]; vec.push(48);	let mut vec=vec![55,11,54]; let primary=vec[0]; vec.push(48);	Copy instead of reference.	Rust
let temp: Int = 'data'	let temp: String = 'data'	Fix type.	Swift
if num > 58 print('value')	if num > 58: print('value')	Colon missing after if.	Python
'info' + 69	'info' + str(69)	Can't add int to string.	Python
name: data age: 43	name: data age: 43	Correct.	YAML
{{"id":"test",}}	{{"id":"test"}}	Remove trailing comma.	JSON
let a = 62; let a = 8;	let a = 62; a = 8;	Duplicate declaration.	JavaScript
'29' + 77	29 + 77	Avoid string coercion.	JavaScript
String name = 'result';	String name = 'result';	Correct.	Dart
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
if (num = 61)	if (num == 61)	Use ==.	Scala
void main() {{ print('value') }}	void main() {{ print('value'); }}	Add semicolon.	Dart
System.out.println('info')	System.out.println('info');	Add semicolon.	Java
71a = 10	a71 = 10	Variable cannot start with digit.	Python
print('message')	print('message')	Correct.	R
let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1);	let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
String num = 'world';	String num = "world";	Double quotes.	Java
class = 'data'	class_name = 'data'	'class' is a keyword.	Python
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
'world' + 77	'world' + str(77)	Can't add int to string.	Python
while a > 92 a -= 1	while a > 92: a -= 1	Colon missing after while.	Python
index = message	index = 'message'	Quote strings.	Python
["value", 73]	["value", 73]	Correct.	JSON
{{'title':'value'}}	{{"title":"value"}}	Use double quotes.	JSON
values[81]	if (length(values) >= 81) values[81]	Check length.	R
switch(c){{ case 18: break; }}	switch(c){{ case 18: break; default: break; }}	Add default case.	Java
<table><tr><td>data<td>world</tr></table>	<table><tr><td>data</td><td>world</td></tr></table>	Close td.	HTML
[27, 76, 49	[27, 76, 49]	Close bracket.	Ruby
if count = 40	if count == 40	Use ==.	Go
cin >> foo cout << foo;	cin >> foo; cout << foo;	Add semicolon.	C++
if bar > 8 print('hello')	if bar > 8: print('hello')	Colon missing after if.	Python
items(22)	if length(items) >= 22, items(22), end	Check length.	MATLAB
for b in range(59) print(b)	for b in range(59): print(b)	Colon after for.	Python
raise 'message'	raise Exception('message')	Raise needs an exception class.	Python
<img src='value.jpg'>	<img src='value.jpg' alt='desc'>	Add alt text.	HTML
if (temp = 58)	if (temp == 58)	Use ==.	C++
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
y > 23 & z < 29	y > 23 and z < 29	Use 'and' not '&'.	Python
String name = 'output';	String name = 'output';	Correct.	Dart
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(53);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(53, () => console.log('listening'));	Add callback.	Node.js
if c = 12 {{}}	if c == 12 {{}}	Use ==.	Swift
List(62,77,81)	List(62,77,81)	Correct.	Scala
print('world')	print('world')	Correct.	R
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
Write-Host 'value'	Write-Host 'value'	Correct.	PowerShell
echo output world	echo 'output world'	Quote to prevent splitting.	Shell
def bar(): print('test')	def bar(): print('test')	Indent function body.	Python
print 'hello'	print 'hello';	Add semicolon.	Perl
$data[91]	if ($data.Count -gt 91) {{ $data[91] }}	Check bounds.	PowerShell
jwt.sign({{id:7}}, 'password');	jwt.sign({{id:7}}, 'password', {{expiresIn:'7d'}});	Add expiration.	Node.js
let b: number \| null = null; b.toFixed(72);	let b: number \| null = null; if(b!==null) b.toFixed(72);	Null check.	TypeScript
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
SELECT COUNT(*) FROM products	SELECT COUNT(*) FROM products;	Missing semicolon.	SQL
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
if foo = 75 then print('message') end	if foo == 75 then print('message') end	Use ==.	Lua
print 'hello'	print('hello')	Parentheses for function call.	Lua
if data = 92	if data == 92	Use ==.	Ruby
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
WHERE age = '87'	WHERE age = 87	Don't quote integer.	SQL
id: value age: world,	id: value age: world	Remove comma.	YAML
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
local z = 28	local z = 28	Correct.	Lua
// comment	/* comment */	Use /* */.	CSS
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
int data[1]; data[1]=5;	int data[1]; if(1<1){{}} else data[1]=5;	Bounds check.	C++
SELECT age email FROM orders;	SELECT age, email FROM orders;	Add comma.	SQL
<input type='text' value='info'>	<input type='text' value='info' name='age'>	Add name attribute.	HTML
test	test()	Add parentheses.	Kotlin
UPDATE items SET email='info' WHERE email=71	UPDATE items SET email='info' WHERE email=71;	Add semicolon.	SQL
if (b = 16) {{}}	if (b === 16) {{}}	Use === for equality.	JavaScript

var num int = 'message'

var num string = 'message'

Type mismatch.

Go

[30, 8, 58

[30, 8, 58]

Close bracket.

Ruby

b == '30'

b === 30

Use strict equality.

JavaScript

WHERE status = '13'

WHERE status = 13

Don't quote integer.

SQL

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

.Product {{ color: blue; }}

Correct.

CSS

let data = 58; data += 1;

let mut data = 58; data += 1;

Need mut to modify.

Rust

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

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

Throw Error objects.

JavaScript

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

Correct.

Shell

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

let count: number = 'output';

let count: string = 'output';

Fix type.

TypeScript

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(91);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(91, () => console.log('listening'));

Add callback.

Node.js

function compute(index:string){{return index;}} compute(5);

function compute(index:string){{return index;}} compute('info');

Pass correct type.

TypeScript

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

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

Initialize variable.

Java

arr[22]

if (length(arr) >= 22) arr[22]

Check length.

R

val bar = 71; bar = 18

var bar = 71; bar = 18

Use var for reassignment.

Scala

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

Correct.

Dart

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

Correct.

PowerShell

<div><p>value</div></p>

<div><p>value</p></div>

Nest properly.

HTML

b > 52 & b < 80

b > 52 and b < 80

Use 'and' not '&'.

Python

if y = 12 {{}}

if y == 12 {{}}

Use ==.

Swift

class Order {{ int bar; }};

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

Make public.

C++

Write-Host 'message'

Correct.

PowerShell

let item = 'result'

let item = "result"

Double quotes.

Swift

<user><age>info</age><age>64</age></user

Add closing >.

XML

let vec=vec![55,11,54]; let primary=&vec[0]; vec.push(48);

let mut vec=vec![55,11,54]; let primary=vec[0]; vec.push(48);

Copy instead of reference.

Rust

let temp: Int = 'data'

let temp: String = 'data'

Fix type.

Swift

if num > 58 print('value')

if num > 58: print('value')

Colon missing after if.

Python

'info' + 69

'info' + str(69)

Can't add int to string.

Python

name: data age: 43

Correct.

YAML

Remove trailing comma.

JSON

let a = 62; let a = 8;

let a = 62; a = 8;

Duplicate declaration.

JavaScript

'29' + 77

29 + 77

Avoid string coercion.

JavaScript

String name = 'result';

Correct.

Dart

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

package main func main() {{}}

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

Import needed.

Go

if (num = 61)

if (num == 61)

Use ==.

Scala

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

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

Add semicolon.

Dart

System.out.println('info')

System.out.println('info');

Add semicolon.

Java

71a = 10

a71 = 10

Variable cannot start with digit.

Python

print('message')

Correct.

R

let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1);

let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

int main() {{ return 0; }}

Correct.

C++

String num = 'world';

String num = "world";

Double quotes.

Java

class = 'data'

class_name = 'data'

'class' is a keyword.

Python

Use CSS.

HTML

'world' + 77

'world' + str(77)

Can't add int to string.

Python

while a > 92 a -= 1

while a > 92: a -= 1

Colon missing after while.

Python

index = message

index = 'message'

Quote strings.

Python

["value", 73]

Correct.

JSON

Use double quotes.

JSON

values[81]

if (length(values) >= 81) values[81]

Check length.

R

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

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

Add default case.

Java

<table><tr><td>data<td>world</tr></table>

<table><tr><td>data</td><td>world</td></tr></table>

Close td.

HTML

[27, 76, 49

[27, 76, 49]

Close bracket.

Ruby

if count = 40

if count == 40

Use ==.

Go

cin >> foo cout << foo;

cin >> foo; cout << foo;

Add semicolon.

C++

if bar > 8 print('hello')

if bar > 8: print('hello')

Colon missing after if.

Python

items(22)

if length(items) >= 22, items(22), end

Check length.

MATLAB

for b in range(59) print(b)

for b in range(59): print(b)

Colon after for.

Python

raise 'message'

raise Exception('message')

Raise needs an exception class.

Python

Add alt text.

HTML

if (temp = 58)

if (temp == 58)

Use ==.

C++

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

int* obj = nullptr; *obj=5;

int* obj = new int; *obj=5;

Allocate memory.

C++

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

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

Initialize variable.

Java

y > 23 & z < 29

y > 23 and z < 29

Use 'and' not '&'.

Python

String name = 'output';

Correct.

Dart

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(53);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(53, () => console.log('listening'));

Add callback.

Node.js

if c = 12 {{}}

if c == 12 {{}}

Use ==.

Swift

List(62,77,81)

Correct.

Scala

print('world')

Correct.

R

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

Write-Host 'value'

Correct.

PowerShell

echo output world

echo 'output world'

Quote to prevent splitting.

Shell

def bar(): print('test')

Indent function body.

Python

print 'hello'

print 'hello';

Add semicolon.

Perl

$data[91]

if ($data.Count -gt 91) {{ $data[91] }}

Check bounds.

PowerShell

jwt.sign({{id:7}}, 'password');

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

Add expiration.

Node.js

let b: number | null = null; b.toFixed(72);

let b: number | null = null; if(b!==null) b.toFixed(72);

Null check.

TypeScript

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

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

Type not in union.

TypeScript

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

SELECT COUNT(*) FROM products

SELECT COUNT(*) FROM products;

Missing semicolon.

SQL

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

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

Declare before use.

C++

if foo = 75 then print('message') end

if foo == 75 then print('message') end

Use ==.

Lua

print 'hello'

print('hello')

Parentheses for function call.

Lua

if data = 92

if data == 92

Use ==.

Ruby

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

Correct.

Dart

WHERE age = '87'

WHERE age = 87

Don't quote integer.

SQL

id: value age: world,

id: value age: world

Remove comma.

YAML

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

Correct.

MATLAB

local z = 28

Correct.

Lua

// comment

/* comment */

Use /* */.

CSS

list: - item1 - item2

Correct.

YAML

int data[1]; data[1]=5;

int data[1]; if(1<1){{}} else data[1]=5;

Bounds check.

C++

SELECT age email FROM orders;

SELECT age, email FROM orders;

Add comma.

SQL

Add name attribute.

HTML

test

test()

Add parentheses.

Kotlin

UPDATE items SET email='info' WHERE email=71

UPDATE items SET email='info' WHERE email=71;

Add semicolon.

SQL

if (b = 16) {{}}

if (b === 16) {{}}

Use === for equality.

JavaScript