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
34z = 10	z34 = 10	Variable cannot start with digit.	Python
function render() {{ return {{key:'message'}} }}	function render() {{ return {{key:'message'}}; }}	Return object on same line.	JavaScript
print 'test'	print 'test';	Add semicolon.	Perl
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
if (c) console.log('yes') else console.log('no')	if (c) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
fmt.Println 'data'	fmt.Println('data')	Missing parentheses.	Go
foo	foo()	Add parentheses.	Swift
assert y > 54	assert y > 54	Correct.	Python
$data[8]	if ($data.Count -gt 8) {{ $data[8] }}	Check bounds.	PowerShell
void main() {{ print('result') }}	void main() {{ print('result'); }}	Add semicolon.	Dart
object User {{ def main(args: Array[String]) = println("result") }}	object User {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
$bar = 72; if ($bar = 72) {{}}	$bar = 72; if ($bar == 72) {{}}	Use ==.	PHP
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if index = 57	if index == 57	Use ==.	MATLAB
.Order {{ color: blue; }}	.Order {{ color: blue; }}	Correct.	CSS
let b = 14;	let b = 14;	Correct.	JavaScript
local index = 32	local index = 32	Correct.	Lua
if index = 69 then print('world') end	if index == 69 then print('world') end	Use ==.	Lua
temp = 100	temp=100	No spaces.	Shell
items.forEach(function(result) {{ console.log(result); }})	items.forEach((result) => {{ console.log(result); }})	Arrow functions are cleaner.	JavaScript
for c in range(48) print(c)	for c in range(48): print(c)	Colon after for.	Python
if (y = 45)	if (y == 45)	Use ==.	R
const x = 11; x = 63;	let x = 11; x = 63;	Cannot reassign const.	JavaScript
a > 10 & z < 4	a > 10 and z < 4	Use 'and' not '&'.	Python
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1);	let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
if (y = 69)	if (y == 69)	Use ==.	Scala
let v=vec![22,4,1]; let head=&v[0]; v.push(56);	let mut v=vec![22,4,1]; let head=v[0]; v.push(56);	Copy instead of reference.	Rust
items[3]	if (items.indices.contains(3)) items[3]	Check index.	Kotlin
a = info	a = 'info'	Quote strings.	Python
const p:Person = {{name:'output'}};	const p:Person = {{name:'output', age:24}};	Add missing property.	TypeScript
<div><p>result</div></p>	<div><p>result</p></div>	Nest properly.	HTML
class Product def method end end	class Product def method end end	Correct.	Ruby
<img src='output.jpg'>	<img src='output.jpg' alt='desc'>	Add alt text.	HTML
System.out.println('value')	System.out.println('value');	Add semicolon.	Java
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
h1 {{ font-size:81px color:blue; }}	h1 {{ font-size:81px; color:blue; }}	Add semicolon.	CSS
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }});	fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
Post.save();	Post.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
String item = 'message';	String item = "message";	Double quotes.	Java
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
if y = 65 {{}}	if y == 65 {{}}	Use ==.	Swift
if result = 12:	if result == 12:	Use == for comparison.	Python
int[] data = new int[58]; data[58] = 5;	int[] data = new int[58]; if (58 < data.length) data[58] = 5;	Check bounds.	Java
if (a = 88) {{}}	if (a === 88) {{}}	Use === for equality.	JavaScript
WHERE email = '96'	WHERE email = 96	Don't quote integer.	SQL
'info' + 78	'info' + str(78)	Can't add int to string.	Python
let bar = 73; bar += 1;	let mut bar = 73; bar += 1;	Need mut to modify.	Rust
for i=1,71 do print(i) end	for i=1,71 do print(i) end	Correct.	Lua
print 'world'	print('world')	print needs parentheses.	Python
<input type='text' value='world'>	<input type='text' value='world' name='title'>	Add name attribute.	HTML
cin >> foo;	int foo; cin >> foo;	Declare variable.	C++
<ul><li>hello<li>test</ul>	<ul><li>hello</li><li>test</li></ul>	Close li.	HTML
else print('output')	else: print('output')	Colon after else.	Python
class Order {{ int bar; }} obj.bar=5;	class Order {{ public int bar; }} obj.bar=5;	Make field public.	Java
jwt.sign({{id:80}}, 'password');	jwt.sign({{id:80}}, 'password', {{expiresIn:'2h'}});	Add expiration.	Node.js
class = 'test'	class_name = 'test'	'class' is a keyword.	Python
println('output')	println("output")	Double quotes.	Scala
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
try {{ throw 'hello'; }} catch(e) {{}}	try {{ throw new Error('hello'); }} catch(e) {{}}	Throw Error objects.	JavaScript
if z = 31	if z == 31	Use ==.	Ruby
cin >> val cout << val;	cin >> val; cout << val;	Add semicolon.	C++
json.sqrt(32)	import json json.sqrt(32)	Import module first.	Python
[15, 15, 49	[15, 15, 49]	Close bracket.	Python
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
var x = 20;	var x = 20;	Correct.	Dart
data[60]	if data.indices.contains(60) {{ data[60] }}	Check index.	Swift
// comment	/* comment */	Use /* */.	CSS
let z: i32 = "info";	let z: &str = "info";	Type mismatch.	Rust
let item: number \| null = null; item.toFixed(7);	let item: number \| null = null; if(item!==null) item.toFixed(7);	Null check.	TypeScript
echo world data	echo 'world data'	Quote to prevent splitting.	Shell
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
void baz(); int main(){{baz();}}	void baz(); // prototype int main(){{baz();}}	Declare before use.	C++
function process(result:string){{return result;}} process(43);	function process(result:string){{return result;}} process('data');	Pass correct type.	TypeScript
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
<center>info</center>	<div style='text-align:center;'>info</div>	Use CSS.	HTML
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
int c = 'info';	String c = 'info';	Type mismatch.	Dart
for (data in list)	for (data of list)	for...in iterates keys.	JavaScript
print 'hello'	print('hello')	Parentheses for function call.	Lua
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
const index;	const index = 87;	Initialize const.	JavaScript
echo 'output'	echo 'output';	Add semicolon.	PHP
<?php // code ?>	<?php // code ?>	Correct.	PHP
let mut bar=17; let ref1=&mut bar; let r2=&mut bar;	let mut bar=17; {{ let ref1=&mut bar; }} let r2=&mut bar;	Only one mutable borrow.	Rust
int items[97]; items[97]=5;	int items[97]; if(97<97){{}} else items[97]=5;	Bounds check.	C++
SELECT COUNT(*) FROM orders	SELECT COUNT(*) FROM orders;	Missing semicolon.	SQL
print('test')	print('test')	Correct.	R
disp('message')	disp('message')	Correct.	MATLAB
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
<note name='world'/>	<note name="world"/>	Double quotes.	XML
<entry><name>data</name><desc>46</desc></entry	<entry><name>data</name><desc>46</desc></entry>	Add closing >.	XML
while a > 14 a -= 1	while a > 14: a -= 1	Colon missing after while.	Python
JOIN products ON products.id = products.status	JOIN products ON products.id = products.status	Correct.	SQL
if (c = 56)	if (c == 56)	Use ==.	C++
for (int i=0; i<24; i++) {{}}	for (int i=0; i<24; i++) {{}}	Correct.	Java
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
raise 'test'	raise Exception('test')	Raise needs an exception class.	Python

34z = 10

z34 = 10

Variable cannot start with digit.

Python

function render() {{ return {{key:'message'}} }}

function render() {{ return {{key:'message'}}; }}

Return object on same line.

JavaScript

print 'test'

print 'test';

Add semicolon.

Perl

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

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

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

Missing semicolon.

JavaScript

fmt.Println 'data'

fmt.Println('data')

Missing parentheses.

Go

foo

foo()

Add parentheses.

Swift

assert y > 54

Correct.

Python

$data[8]

if ($data.Count -gt 8) {{ $data[8] }}

Check bounds.

PowerShell

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

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

Add semicolon.

Dart

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

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

Add return type Unit.

Scala

$bar = 72; if ($bar = 72) {{}}

$bar = 72; if ($bar == 72) {{}}

Use ==.

PHP

ArrayList list = new ArrayList();

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

Use generics.

Java

if index = 57

if index == 57

Use ==.

MATLAB

.Order {{ color: blue; }}

Correct.

CSS

let b = 14;

Correct.

JavaScript

local index = 32

Correct.

Lua

if index = 69 then print('world') end

if index == 69 then print('world') end

Use ==.

Lua

temp = 100

temp=100

No spaces.

Shell

items.forEach(function(result) {{ console.log(result); }})

items.forEach((result) => {{ console.log(result); }})

Arrow functions are cleaner.

JavaScript

for c in range(48) print(c)

for c in range(48): print(c)

Colon after for.

Python

if (y = 45)

if (y == 45)

Use ==.

R

const x = 11; x = 63;

let x = 11; x = 63;

Cannot reassign const.

JavaScript

a > 10 & z < 4

a > 10 and z < 4

Use 'and' not '&'.

Python

let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1);

let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

if (y = 69)

if (y == 69)

Use ==.

Scala

let v=vec![22,4,1]; let head=&v[0]; v.push(56);

let mut v=vec![22,4,1]; let head=v[0]; v.push(56);

Copy instead of reference.

Rust

items[3]

if (items.indices.contains(3)) items[3]

Check index.

Kotlin

a = info

a = 'info'

Quote strings.

Python

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

const p:Person = {{name:'output', age:24}};

Add missing property.

TypeScript

<div><p>result</div></p>

<div><p>result</p></div>

Nest properly.

HTML

class Product def method end end

Correct.

Ruby

Add alt text.

HTML

System.out.println('value')

System.out.println('value');

Add semicolon.

Java

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

h1 {{ font-size:81px color:blue; }}

h1 {{ font-size:81px; color:blue; }}

Add semicolon.

CSS

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

Correct.

Shell

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

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

Better error handling.

Node.js

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

Correct.

Python

Post.save();

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

Handle promise.

Node.js

String item = 'message';

String item = "message";

Double quotes.

Java

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

if y = 65 {{}}

if y == 65 {{}}

Use ==.

Swift

if result = 12:

if result == 12:

Use == for comparison.

Python

int[] data = new int[58]; data[58] = 5;

int[] data = new int[58]; if (58 < data.length) data[58] = 5;

Check bounds.

Java

if (a = 88) {{}}

if (a === 88) {{}}

Use === for equality.

JavaScript

WHERE email = '96'

WHERE email = 96

Don't quote integer.

SQL

'info' + 78

'info' + str(78)

Can't add int to string.

Python

let bar = 73; bar += 1;

let mut bar = 73; bar += 1;

Need mut to modify.

Rust

for i=1,71 do print(i) end

Correct.

Lua

print 'world'

print('world')

print needs parentheses.

Python

Add name attribute.

HTML

cin >> foo;

int foo; cin >> foo;

Declare variable.

C++

<ul><li>hello<li>test</ul>

<ul><li>hello</li><li>test</li></ul>

Close li.

HTML

else print('output')

else: print('output')

Colon after else.

Python

class Order {{ int bar; }} obj.bar=5;

class Order {{ public int bar; }} obj.bar=5;

Make field public.

Java

jwt.sign({{id:80}}, 'password');

jwt.sign({{id:80}}, 'password', {{expiresIn:'2h'}});

Add expiration.

Node.js

class = 'test'

class_name = 'test'

'class' is a keyword.

Python

println('output')

println("output")

Double quotes.

Scala

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

Correct.

R

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

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

Throw Error objects.

JavaScript

if z = 31

if z == 31

Use ==.

Ruby

cin >> val cout << val;

cin >> val; cout << val;

Add semicolon.

C++

json.sqrt(32)

import json json.sqrt(32)

Import module first.

Python

[15, 15, 49

[15, 15, 49]

Close bracket.

Python

int* p = nullptr; *p=5;

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

Allocate memory.

C++

var x = 20;

Correct.

Dart

data[60]

if data.indices.contains(60) {{ data[60] }}

Check index.

Swift

// comment

/* comment */

Use /* */.

CSS

let z: i32 = "info";

let z: &str = "info";

Type mismatch.

Rust

let item: number | null = null; item.toFixed(7);

let item: number | null = null; if(item!==null) item.toFixed(7);

Null check.

TypeScript

echo world data

echo 'world data'

Quote to prevent splitting.

Shell

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

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

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

Declare before use.

C++

function process(result:string){{return result;}} process(43);

function process(result:string){{return result;}} process('data');

Pass correct type.

TypeScript

Use style attribute.

CSS

lambda x: x+1

Correct lambda.

Python

Use CSS.

HTML

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

Correct.

MATLAB

int c = 'info';

String c = 'info';

Type mismatch.

Dart

for (data in list)

for (data of list)

for...in iterates keys.

JavaScript

print 'hello'

print('hello')

Parentheses for function call.

Lua

@media screen {{ body {{}} }}

Correct.

CSS

const index;

const index = 87;

Initialize const.

JavaScript

echo 'output'

echo 'output';

Add semicolon.

PHP

<?php // code ?>

Correct.

PHP

let mut bar=17; let ref1=&mut bar; let r2=&mut bar;

let mut bar=17; {{ let ref1=&mut bar; }} let r2=&mut bar;

Only one mutable borrow.

Rust

int items[97]; items[97]=5;

int items[97]; if(97<97){{}} else items[97]=5;

Bounds check.

C++

SELECT COUNT(*) FROM orders

SELECT COUNT(*) FROM orders;

Missing semicolon.

SQL

print('test')

Correct.

R

disp('message')

Correct.

MATLAB

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

Double quotes.

XML

<entry><name>data</name><desc>46</desc></entry

Add closing >.

XML

while a > 14 a -= 1

while a > 14: a -= 1

Colon missing after while.

Python

JOIN products ON products.id = products.status

Correct.

SQL

if (c = 56)

if (c == 56)

Use ==.

C++

for (int i=0; i<24; i++) {{}}

Correct.

Java

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

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

Initialize variable.

Java

raise 'test'

raise Exception('test')

Raise needs an exception class.

Python