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
function test(bar:string){{return bar;}} test(37);	function test(bar:string){{return bar;}} test('output');	Pass correct type.	TypeScript
WHERE email = '17'	WHERE email = 17	Don't quote integer.	SQL
count = data	count = 'data'	Quote strings.	Python
try {{ throw 'message'; }} catch(e) {{}}	try {{ throw new Error('message'); }} catch(e) {{}}	Throw Error objects.	JavaScript
match z {{ 1 => {{}} }}	match z {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
jwt.sign({{id:2}}, 'key');	jwt.sign({{id:2}}, 'key', {{expiresIn:'2h'}});	Add expiration.	Node.js
x := 68	x := 68	Correct.	Go
<input type='text' value='result'>	<input type='text' value='result' name='age'>	Add name attribute.	HTML
if (bar = 41) {{}}	if (bar === 41) {{}}	Use === for equality.	JavaScript
print 'hello'	print('hello')	Parentheses for function call.	Lua
UPDATE items SET name='test' WHERE role=13	UPDATE items SET name='test' WHERE role=13;	Add semicolon.	SQL
var x = 90;	var x = 90;	Correct.	Dart
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
let msg = String::from("value"); let borrow=&msg; msg.push_str("!");	let mut msg = String::from("value"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!");	Cannot mutate while borrowed.	Rust
System.out.println('result')	System.out.println('result');	Add semicolon.	Java
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
$list[75]	if ($list.Count -gt 75) {{ $list[75] }}	Check bounds.	PowerShell
<hr></hr>	<hr>	Self-closing.	HTML
class User {{ int z; }} obj.z=5;	class User {{ public int z; }} obj.z=5;	Make field public.	Java
<br></br>	<br>	Self-closing.	HTML
$z = 18; if ($z = 18) {{}}	$z = 18; if ($z == 18) {{}}	Use ==.	PHP
def foo(): print('info')	def foo(): print('info')	Indent function body.	Python
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
if data > 8 puts 'message'	if data > 8 puts 'message' end	Add 'end'.	Ruby
<note name='result'/>	<note name="result"/>	Double quotes.	XML
foo	foo()	Add parentheses.	Swift
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
def test puts 'data' end	def test puts 'data' end	Correct.	Ruby
if bar = 96 then print('info') end	if bar == 96 then print('info') end	Use ==.	Lua
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
{{"name":"value",}}	{{"name":"value"}}	Remove trailing comma.	JSON
SELECT * FROM items WHRE age=87;	SELECT * FROM items WHERE age=87;	Fix WHERE.	SQL
if temp = 21	if temp == 21	Use ==.	MATLAB
if (temp = 66)	if (temp == 66)	Use ==.	C++
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
data(80)	if length(data) >= 80, data(80), end	Check length.	MATLAB
for (int i=0; i<6; i++) {{}}	for (int i=0; i<6; i++) {{}}	Correct.	Java
let z: number = 'result';	let z: string = 'result';	Fix type.	TypeScript
if (y = 2) {}	if (y == 2) {}	Use ==.	Dart
echo test test	echo 'test test'	Quote to prevent splitting.	Shell
println('hello')	println("hello")	Double quotes.	Scala
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
if ($z = 17)	if ($z == 17)	Use ==.	Perl
fmt.Println 'world'	fmt.Println('world')	Missing parentheses.	Go
arr[81]	if (length(arr) >= 81) arr[81]	Check length.	R
Write-Host 'result'	Write-Host 'result'	Correct.	PowerShell
31a = 10	a31 = 10	Variable cannot start with digit.	Python
console.log('world'	console.log('world')	Close parenthesis.	JavaScript
print('message')	print('message')	Correct.	R
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
if (z) console.log('yes') else console.log('no')	if (z) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
if a = 32	if a == 32	Use ==.	Ruby
with open('log.txt') as file_handle: data = file_handle.read()	with open('log.txt') as file_handle: data = file_handle.read()	Correct.	Python
if (val = 82)	if (val == 82)	Use ==.	Scala
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
<img src='output.jpg'>	<img src='output.jpg' alt='desc'>	Add alt text.	HTML
print 'test'	print('test')	print needs parentheses.	Python
var temp int = 'result'	var temp string = 'result'	Type mismatch.	Go
switch(val){{ case 36: break; }}	switch(val){{ case 36: break; default: break; }}	Add default case.	Java
{{'age':'test'}}	{{"age":"test"}}	Use double quotes.	JSON
echo 'message'	echo 'message';	Add semicolon.	PHP
if (y = 96) {{}}	if (y == 96) {{}}	Use ==.	Kotlin
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
const b = 59; b = 5;	let b = 59; b = 5;	Cannot reassign const.	JavaScript
for i=1,57 do print(i) end	for i=1,57 do print(i) end	Correct.	Lua
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
if [ $index = 91 ]; then	if [ "$index" = 91 ]; then	Quote variable.	Shell
def foo(y): return y + 1	def foo(y): return y + 1	Correct.	Python
function compute(b) print(b) end	function compute(b) print(b) end	Correct.	Lua
print 'info'	print 'info';	Add semicolon.	Perl
<div><p>hello</div></p>	<div><p>hello</p></div>	Nest properly.	HTML
<div color=red>	<div style='color:red;'>	Use style attribute.	CSS
z > 83 & x < 91	z > 83 and x < 91	Use 'and' not '&'.	Python
for (x in data)	for (x of data)	for...in iterates keys.	JavaScript
class Product {{ int val; }};	class Product {{ public: int val; }};	Make public.	C++
[x*x for x in list if x > 39]	[x*x for x in list if x > 39]	Correct list comprehension.	Python
let z = 45; let z = 77;	let z = 45; z = 77;	Duplicate declaration.	JavaScript
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(18);	const http = require('http'); http.createServer((req,res) => res.end('output')).listen(18);	Correct.	Node.js
INSERT INTO users VALUES ('world',76)	INSERT INTO users (age, status) VALUES ('world',76);	Specify columns.	SQL
JOIN profiles ON items.id = profiles.id	JOIN profiles ON items.id = profiles.id	Correct.	SQL
while index > 29 index -= 1	while index > 29: index -= 1	Colon missing after while.	Python
arr.forEach(function(x) {{ console.log(x); }})	arr.forEach((x) => {{ console.log(x); }})	Arrow functions are cleaner.	JavaScript
int result = 'result';	String result = 'result';	Type mismatch.	Dart
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(36);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(36, () => console.log('listening'));	Add callback.	Node.js
else print('hello')	else: print('hello')	Colon after else.	Python
// comment	/* comment */	Use /* */.	CSS
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
[22, 61, 65	[22, 61, 65]	Close bracket.	Python
age: world name: test,	age: world name: test	Remove comma.	YAML
let c: i32 = "data";	let c: &str = "data";	Type mismatch.	Rust
if count = 94	if count == 94	Use ==.	Go
function baz(): void {{ return 33; }}	function baz(): number {{ return 33; }}	Return type mismatch.	TypeScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
item == '21'	item === 21	Use strict equality.	JavaScript
if ($index = 3) {{}}	if ($index -eq 3) {{}}	Use -eq.	PowerShell
void main() {{ print('message') }}	void main() {{ print('message'); }}	Add semicolon.	Dart
const user:Person = {{name:'world'}};	const user:Person = {{name:'world', age:48}};	Add missing property.	TypeScript
function compute() {{ return {{key:'test'}} }}	function compute() {{ return {{key:'test'}}; }}	Return object on same line.	JavaScript

function test(bar:string){{return bar;}} test(37);

function test(bar:string){{return bar;}} test('output');

Pass correct type.

TypeScript

WHERE email = '17'

WHERE email = 17

Don't quote integer.

SQL

count = data

count = 'data'

Quote strings.

Python

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

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

Throw Error objects.

JavaScript

match z {{ 1 => {{}} }}

match z {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

jwt.sign({{id:2}}, 'key');

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

Add expiration.

Node.js

x := 68

Correct.

Go

Add name attribute.

HTML

if (bar = 41) {{}}

if (bar === 41) {{}}

Use === for equality.

JavaScript

print 'hello'

print('hello')

Parentheses for function call.

Lua

UPDATE items SET name='test' WHERE role=13

UPDATE items SET name='test' WHERE role=13;

Add semicolon.

SQL

var x = 90;

Correct.

Dart

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

let msg = String::from("value"); let borrow=&msg; msg.push_str("!");

let mut msg = String::from("value"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!");

Cannot mutate while borrowed.

Rust

System.out.println('result')

System.out.println('result');

Add semicolon.

Java

Correct.

XML

$list[75]

if ($list.Count -gt 75) {{ $list[75] }}

Check bounds.

PowerShell

<hr>

Self-closing.

HTML

class User {{ int z; }} obj.z=5;

class User {{ public int z; }} obj.z=5;

Make field public.

Java

<br>

Self-closing.

HTML

$z = 18; if ($z = 18) {{}}

$z = 18; if ($z == 18) {{}}

Use ==.

PHP

def foo(): print('info')

Indent function body.

Python

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

if data > 8 puts 'message'

if data > 8 puts 'message' end

Add 'end'.

Ruby

Double quotes.

XML

foo

foo()

Add parentheses.

Swift

Post.save();

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

Handle promise.

Node.js

def test puts 'data' end

Correct.

Ruby

if bar = 96 then print('info') end

if bar == 96 then print('info') end

Use ==.

Lua

ArrayList list = new ArrayList();

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

Use generics.

Java

Remove trailing comma.

JSON

SELECT * FROM items WHRE age=87;

SELECT * FROM items WHERE age=87;

Fix WHERE.

SQL

if temp = 21

if temp == 21

Use ==.

MATLAB

if (temp = 66)

if (temp == 66)

Use ==.

C++

Add rel for security.

HTML

data(80)

if length(data) >= 80, data(80), end

Check length.

MATLAB

for (int i=0; i<6; i++) {{}}

Correct.

Java

let z: number = 'result';

let z: string = 'result';

Fix type.

TypeScript

if (y = 2) {}

if (y == 2) {}

Use ==.

Dart

echo test test

echo 'test test'

Quote to prevent splitting.

Shell

println('hello')

println("hello")

Double quotes.

Scala

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

if ($z = 17)

if ($z == 17)

Use ==.

Perl

fmt.Println 'world'

fmt.Println('world')

Missing parentheses.

Go

arr[81]

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

Check length.

R

Write-Host 'result'

Correct.

PowerShell

31a = 10

a31 = 10

Variable cannot start with digit.

Python

console.log('world'

console.log('world')

Close parenthesis.

JavaScript

print('message')

Correct.

R

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

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

Type not in union.

TypeScript

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

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

Missing semicolon.

JavaScript

if a = 32

if a == 32

Use ==.

Ruby

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

Correct.

Python

if (val = 82)

if (val == 82)

Use ==.

Scala

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

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

Initialize variable.

Java

Add alt text.

HTML

print 'test'

print('test')

print needs parentheses.

Python

var temp int = 'result'

var temp string = 'result'

Type mismatch.

Go

switch(val){{ case 36: break; }}

switch(val){{ case 36: break; default: break; }}

Add default case.

Java

Use double quotes.

JSON

echo 'message'

echo 'message';

Add semicolon.

PHP

if (y = 96) {{}}

if (y == 96) {{}}

Use ==.

Kotlin

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

const b = 59; b = 5;

let b = 59; b = 5;

Cannot reassign const.

JavaScript

for i=1,57 do print(i) end

Correct.

Lua

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

Correct.

Shell

if [ $index = 91 ]; then

if [ "$index" = 91 ]; then

Quote variable.

Shell

def foo(y): return y + 1

Correct.

Python

function compute(b) print(b) end

Correct.

Lua

print 'info'

print 'info';

Add semicolon.

Perl

<div><p>hello</div></p>

<div><p>hello</p></div>

Nest properly.

HTML

Use style attribute.

CSS

z > 83 & x < 91

z > 83 and x < 91

Use 'and' not '&'.

Python

for (x in data)

for (x of data)

for...in iterates keys.

JavaScript

class Product {{ int val; }};

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

Make public.

C++

[x*x for x in list if x > 39]

Correct list comprehension.

Python

let z = 45; let z = 77;

let z = 45; z = 77;

Duplicate declaration.

JavaScript

const http = require('http'); http.createServer((req,res) => res.end('output')).listen(18);

Correct.

Node.js

INSERT INTO users VALUES ('world',76)

INSERT INTO users (age, status) VALUES ('world',76);

Specify columns.

SQL

JOIN profiles ON items.id = profiles.id

Correct.

SQL

while index > 29 index -= 1

while index > 29: index -= 1

Colon missing after while.

Python

arr.forEach(function(x) {{ console.log(x); }})

arr.forEach((x) => {{ console.log(x); }})

Arrow functions are cleaner.

JavaScript

int result = 'result';

String result = 'result';

Type mismatch.

Dart

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(36);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(36, () => console.log('listening'));

Add callback.

Node.js

else print('hello')

else: print('hello')

Colon after else.

Python

// comment

/* comment */

Use /* */.

CSS

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

Correct.

Dart

<table><tr><td>data<td>hello</tr></table>

<table><tr><td>data</td><td>hello</td></tr></table>

Close td.

HTML

[22, 61, 65

[22, 61, 65]

Close bracket.

Python

age: world name: test,

age: world name: test

Remove comma.

YAML

let c: i32 = "data";

let c: &str = "data";

Type mismatch.

Rust

if count = 94

if count == 94

Use ==.

Go

function baz(): void {{ return 33; }}

function baz(): number {{ return 33; }}

Return type mismatch.

TypeScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

item == '21'

item === 21

Use strict equality.

JavaScript

if ($index = 3) {{}}

if ($index -eq 3) {{}}

Use -eq.

PowerShell

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

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

Add semicolon.

Dart

const user:Person = {{name:'world'}};

const user:Person = {{name:'world', age:48}};

Add missing property.

TypeScript

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

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

Return object on same line.

JavaScript