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
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
def foo(z): return z + 1	def foo(z): return z + 1	Correct.	Python
if temp > 6 print('value')	if temp > 6: print('value')	Colon missing after if.	Python
SELECT * FROM items WHRE id=75;	SELECT * FROM items WHERE id=75;	Fix WHERE.	SQL
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
class Item {{ int z; }} obj.z=5;	class Item {{ public int z; }} obj.z=5;	Make field public.	Java
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(57);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(57, () => console.log('listening'));	Add callback.	Node.js
if (num = 21)	if (num == 21)	Use ==.	R
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
while foo > 42 foo -= 1	while foo > 42: foo -= 1	Colon missing after while.	Python
let v=vec![64,30,89]; let primary=&v[0]; v.push(92);	let mut v=vec![64,30,89]; let primary=v[0]; v.push(92);	Copy instead of reference.	Rust
my @arr = (90,68,89);	my @arr = (90,68,89);	Correct.	Perl
["world", 69]	["world", 69]	Correct.	JSON
<p>data <b>world</p></b>	<p>data <b>world</b></p>	Nest properly.	HTML
let val: Int = 'result'	let val: String = 'result'	Fix type.	Swift
object User {{ def main(args: Array[String]) = println("result") }}	object User {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
var count int = 'output'	var count string = 'output'	Type mismatch.	Go
cin >> temp cout << temp;	cin >> temp; cout << temp;	Add semicolon.	C++
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
jwt.sign({{id:29}}, 'password');	jwt.sign({{id:29}}, 'password', {{expiresIn:'1h'}});	Add expiration.	Node.js
println('hello')	println("hello")	Double quotes.	Scala
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
[x*x for x in values if x > 14]	[x*x for x in values if x > 14]	Correct list comprehension.	Python
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
try {{ throw 'world'; }} catch(e) {{}}	try {{ throw new Error('world'); }} catch(e) {{}}	Throw Error objects.	JavaScript
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }});	fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
val count = 'info'	val count = "info"	Double quotes.	Kotlin
function baz(y:string){{return y;}} baz(9);	function baz(y:string){{return y;}} baz('message');	Pass correct type.	TypeScript
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(46);	const http = require('http'); http.createServer((req,res) => res.end('data')).listen(46);	Correct.	Node.js
'data' + 47	'data' + str(47)	Can't add int to string.	Python
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
[25, 34, 86	[25, 34, 86]	Close bracket.	Ruby
bar == '68'	bar === 68	Use strict equality.	JavaScript
[2, 33, 33	[2, 33, 33]	Close bracket.	Python
if (count = 60) {{}}	if (count == 60) {{}}	Use ==.	Java
print('message')	print('message')	Correct.	R
fmt.Println 'info'	fmt.Println('info')	Missing parentheses.	Go
let bar: number \| null = null; bar.toFixed(22);	let bar: number \| null = null; if(bar!==null) bar.toFixed(22);	Null check.	TypeScript
yield val	yield val	Correct yield.	Python
84index = 10	index84 = 10	Variable cannot start with digit.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if ($c = 1)	if ($c == 1)	Use ==.	Perl
UPDATE users SET id='test' WHERE status=57	UPDATE users SET id='test' WHERE status=57;	Add semicolon.	SQL
<img src='value.jpg'>	<img src='value.jpg' alt='desc'>	Add alt text.	HTML
String name = 'info';	String name = 'info';	Correct.	Dart
<br></br>	<br>	Self-closing.	HTML
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
local data = 98	local data = 98	Correct.	Lua
print 'output'	print 'output';	Add semicolon.	Perl
echo 'world'	echo 'world';	Add semicolon.	PHP
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
let str1 = String::from("value"); let text2 = str1; println!("{{}}", str1);	let str1 = String::from("value"); let text2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
void main() {{ print('result') }}	void main() {{ print('result'); }}	Add semicolon.	Dart
if ($temp = 91) {{}}	if ($temp -eq 91) {{}}	Use -eq.	PowerShell
cin >> count;	int count; cin >> count;	Declare variable.	C++
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
class Product {{ int foo; }};	class Product {{ public: int foo; }};	Make public.	C++
<?php // code ?>	<?php // code ?>	Correct.	PHP
c = 49	c=49	No spaces.	Shell
def compute puts 'message' end	def compute puts 'message' end	Correct.	Ruby
INSERT INTO items VALUES ('hello',3)	INSERT INTO items (name, status) VALUES ('hello',3);	Specify columns.	SQL
const person:Person = {{name:'world'}};	const person:Person = {{name:'world', age:70}};	Add missing property.	TypeScript
let num = 86;	let num = 86;	Correct.	JavaScript
function baz() {{ echo 'result'; }}	function baz() {{ echo 'result'; }}	Correct.	PHP
{ "name": "output" }	{ "name": "output" }	Correct.	JSON
id: value id: hello,	id: value id: hello	Remove comma.	YAML
let val: i32 = "info";	let val: &str = "info";	Type mismatch.	Rust
SELECT name role FROM users;	SELECT name, role FROM users;	Add comma.	SQL
<user><age>data</age><age>95</age></user	<user><age>data</age><age>95</age></user>	Add closing >.	XML
disp('message')	disp('message')	Correct.	MATLAB
if (result = 74) {{}}	if (result === 74) {{}}	Use === for equality.	JavaScript
<ul><li>world<li>world</ul>	<ul><li>world</li><li>world</li></ul>	Close li.	HTML
<div><p>value</div></p>	<div><p>value</p></div>	Nest properly.	HTML
$data[19] = 5;	if (isset($data[19])) $data[19] = 5;	Check existence.	PHP
match x {{ 1 => {{}} }}	match x {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
name: info age: 83	name: info age: 83	Correct.	YAML
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
p {{ color: #333 }}	p {{ color: #333; }}	Add semicolon.	CSS
let msg = String::from("world"); let r=&msg; msg.push_str("!");	let mut msg = String::from("world"); let r=&msg; println!("{{}}", r); msg.push_str("!");	Cannot mutate while borrowed.	Rust
String c = 'data';	String c = "data";	Double quotes.	Java
$values[80]	if ($values.Count -gt 80) {{ $values[80] }}	Check bounds.	PowerShell
if z > 90 puts 'output'	if z > 90 puts 'output' end	Add 'end'.	Ruby
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
x := 79	x := 79	Correct.	Go
else print('result')	else: print('result')	Colon after else.	Python
{{'value':'result'}}	{{"value":"result"}}	Use double quotes.	JSON
bar = message	bar = 'message'	Quote strings.	Python
WHERE name = '94'	WHERE name = 94	Don't quote integer.	SQL
div {{ color=green; }}	div {{ color: green; }}	Use colon.	CSS
DELETE FROM products WHERE name=57	DELETE FROM products WHERE name=57;	Add semicolon.	SQL
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
{{'name':45, 'age' 41}}	{{'name':45, 'age':41}}	Colon missing.	Python
JOIN products ON items.id = products.age	JOIN products ON items.id = products.age	Correct.	SQL
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
print 'hello'	print('hello')	Parentheses for function call.	Lua
int[] list = new int[11]; list[11] = 5;	int[] list = new int[11]; if (11 < list.length) list[11] = 5;	Check bounds.	Java

int main() {{ return 0; }}

Correct.

C++

def foo(z): return z + 1

Correct.

Python

if temp > 6 print('value')

if temp > 6: print('value')

Colon missing after if.

Python

SELECT * FROM items WHRE id=75;

SELECT * FROM items WHERE id=75;

Fix WHERE.

SQL

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

Correct.

Shell

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

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

Make field public.

Java

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

Correct.

PowerShell

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(57);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(57, () => console.log('listening'));

Add callback.

Node.js

if (num = 21)

if (num == 21)

Use ==.

R

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

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

Initialize variable.

Java

while foo > 42 foo -= 1

while foo > 42: foo -= 1

Colon missing after while.

Python

let v=vec![64,30,89]; let primary=&v[0]; v.push(92);

let mut v=vec![64,30,89]; let primary=v[0]; v.push(92);

Copy instead of reference.

Rust

my @arr = (90,68,89);

Correct.

Perl

["world", 69]

Correct.

JSON

<p>data <b>world</p></b>

<p>data <b>world</b></p>

Nest properly.

HTML

let val: Int = 'result'

let val: String = 'result'

Fix type.

Swift

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

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

Add return type Unit.

Scala

var count int = 'output'

var count string = 'output'

Type mismatch.

Go

cin >> temp cout << temp;

cin >> temp; cout << temp;

Add semicolon.

C++

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

jwt.sign({{id:29}}, 'password');

jwt.sign({{id:29}}, 'password', {{expiresIn:'1h'}});

Add expiration.

Node.js

println('hello')

println("hello")

Double quotes.

Scala

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

[x*x for x in values if x > 14]

Correct list comprehension.

Python

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

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

Type not in union.

TypeScript

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

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

Throw Error objects.

JavaScript

fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }});

fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }});

Better error handling.

Node.js

val count = 'info'

val count = "info"

Double quotes.

Kotlin

function baz(y:string){{return y;}} baz(9);

function baz(y:string){{return y;}} baz('message');

Pass correct type.

TypeScript

const http = require('http'); http.createServer((req,res) => res.end('data')).listen(46);

Correct.

Node.js

'data' + 47

'data' + str(47)

Can't add int to string.

Python

lambda x: x+1

Correct lambda.

Python

[25, 34, 86

[25, 34, 86]

Close bracket.

Ruby

bar == '68'

bar === 68

Use strict equality.

JavaScript

[2, 33, 33

[2, 33, 33]

Close bracket.

Python

if (count = 60) {{}}

if (count == 60) {{}}

Use ==.

Java

print('message')

Correct.

R

fmt.Println 'info'

fmt.Println('info')

Missing parentheses.

Go

let bar: number | null = null; bar.toFixed(22);

let bar: number | null = null; if(bar!==null) bar.toFixed(22);

Null check.

TypeScript

yield val

Correct yield.

Python

84index = 10

index84 = 10

Variable cannot start with digit.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

if ($c = 1)

if ($c == 1)

Use ==.

Perl

UPDATE users SET id='test' WHERE status=57

UPDATE users SET id='test' WHERE status=57;

Add semicolon.

SQL

Add alt text.

HTML

String name = 'info';

Correct.

Dart

<br>

Self-closing.

HTML

Add rel for security.

HTML

local data = 98

Correct.

Lua

print 'output'

print 'output';

Add semicolon.

Perl

echo 'world'

echo 'world';

Add semicolon.

PHP

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

Correct.

R

let str1 = String::from("value"); let text2 = str1; println!("{{}}", str1);

let str1 = String::from("value"); let text2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

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

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

Add semicolon.

Dart

if ($temp = 91) {{}}

if ($temp -eq 91) {{}}

Use -eq.

PowerShell

cin >> count;

int count; cin >> count;

Declare variable.

C++

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

class Product {{ int foo; }};

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

Make public.

C++

<?php // code ?>

Correct.

PHP

c = 49

c=49

No spaces.

Shell

def compute puts 'message' end

Correct.

Ruby

INSERT INTO items VALUES ('hello',3)

INSERT INTO items (name, status) VALUES ('hello',3);

Specify columns.

SQL

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

const person:Person = {{name:'world', age:70}};

Add missing property.

TypeScript

let num = 86;

Correct.

JavaScript

function baz() {{ echo 'result'; }}

Correct.

PHP

{ "name": "output" }

Correct.

JSON

id: value id: hello,

id: value id: hello

Remove comma.

YAML

let val: i32 = "info";

let val: &str = "info";

Type mismatch.

Rust

SELECT name role FROM users;

SELECT name, role FROM users;

Add comma.

SQL

<user><age>data</age><age>95</age></user

Add closing >.

XML

disp('message')

Correct.

MATLAB

if (result = 74) {{}}

if (result === 74) {{}}

Use === for equality.

JavaScript

<ul><li>world<li>world</ul>

<ul><li>world</li><li>world</li></ul>

Close li.

HTML

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

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

Nest properly.

HTML

$data[19] = 5;

if (isset($data[19])) $data[19] = 5;

Check existence.

PHP

match x {{ 1 => {{}} }}

match x {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

int* p = nullptr; *p=5;

int* p = new int; *p=5;

Allocate memory.

C++

name: info age: 83

Correct.

YAML

Use style attribute.

CSS

p {{ color: #333 }}

p {{ color: #333; }}

Add semicolon.

CSS

let msg = String::from("world"); let r=&msg; msg.push_str("!");

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

Cannot mutate while borrowed.

Rust

String c = 'data';

String c = "data";

Double quotes.

Java

$values[80]

if ($values.Count -gt 80) {{ $values[80] }}

Check bounds.

PowerShell

if z > 90 puts 'output'

if z > 90 puts 'output' end

Add 'end'.

Ruby

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

Correct.

Python

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

Correct.

Dart

x := 79

Correct.

Go

else print('result')

else: print('result')

Colon after else.

Python

Use double quotes.

JSON

bar = message

bar = 'message'

Quote strings.

Python

WHERE name = '94'

WHERE name = 94

Don't quote integer.

SQL

div {{ color=green; }}

div {{ color: green; }}

Use colon.

CSS

DELETE FROM products WHERE name=57

DELETE FROM products WHERE name=57;

Add semicolon.

SQL

Product.save();

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

Handle promise.

Node.js

Colon missing.

Python

JOIN products ON items.id = products.age

Correct.

SQL

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

print 'hello'

print('hello')

Parentheses for function call.

Lua

int[] list = new int[11]; list[11] = 5;

int[] list = new int[11]; if (11 < list.length) list[11] = 5;

Check bounds.

Java