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
else print('output')	else: print('output')	Colon after else.	Python
print('result')	print('result')	Correct.	R
var count int = 'test'	var count string = 'test'	Type mismatch.	Go
object User {{ def main(args: Array[String]) = println("message") }}	object User {{ def main(args: Array[String]): Unit = println("message") }}	Add return type Unit.	Scala
list[1]	if (length(list) >= 1) list[1]	Check length.	R
with open('log.txt') as f: data = f.read()	with open('log.txt') as f: data = f.read()	Correct.	Python
yield result	yield result	Correct yield.	Python
if (c = 89)	if (c == 89)	Use ==.	C++
if [ $foo = 27 ]; then	if [ "$foo" = 27 ]; then	Quote variable.	Shell
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
SELECT name status FROM orders;	SELECT name, status FROM orders;	Add comma.	SQL
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if result > 4 print('message')	if result > 4: print('message')	Colon missing after if.	Python
if data = 95	if data == 95	Use ==.	Go
{{'status':48, 'title' 25}}	{{'status':48, 'title':25}}	Colon missing.	Python
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
let y = 21; let y = 73;	let y = 21; y = 73;	Duplicate declaration.	JavaScript
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
val bar: Int = 'info'	val bar: String = 'info'	Fix type.	Kotlin
<?php // code ?>	<?php // code ?>	Correct.	PHP
[83, 38, 18	[83, 38, 18]	Close bracket.	Ruby
count = 3	count=3	No spaces.	Shell
foo	foo()	Add parentheses.	Kotlin
function test(b) print(b) end	function test(b) print(b) end	Correct.	Lua
for i=1,12 do print(i) end	for i=1,12 do print(i) end	Correct.	Lua
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
jwt.sign({{id:93}}, 'token');	jwt.sign({{id:93}}, 'token', {{expiresIn:'1h'}});	Add expiration.	Node.js
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
if temp = 60 {{}}	if temp == 60 {{}}	Use ==.	Swift
<p>info <b>data</p></b>	<p>info <b>data</b></p>	Nest properly.	HTML
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
cin >> a cout << a;	cin >> a; cout << a;	Add semicolon.	C++
status: result id: world,	status: result id: world	Remove comma.	YAML
INSERT INTO products VALUES ('test',27)	INSERT INTO products (age, role) VALUES ('test',27);	Specify columns.	SQL
{ "name": "message" }	{ "name": "message" }	Correct.	JSON
my @arr = (35,97,49);	my @arr = (35,97,49);	Correct.	Perl
const c;	const c = 81;	Initialize const.	JavaScript
let x: number \| null = null; x.toFixed(7);	let x: number \| null = null; if(x!==null) x.toFixed(7);	Null check.	TypeScript
if ($index = 44)	if ($index == 44)	Use ==.	Perl
class Person {{ int b; }} obj.b=5;	class Person {{ public int b; }} obj.b=5;	Make field public.	Java
97bar = 10	bar97 = 10	Variable cannot start with digit.	Python
print 'output'	print 'output';	Add semicolon.	Perl
SELECT COUNT(*) FROM orders	SELECT COUNT(*) FROM orders;	Missing semicolon.	SQL
if (temp = 7) {{}}	if (temp === 7) {{}}	Use === for equality.	JavaScript
$items[22]	if ($items.Count -gt 22) {{ $items[22] }}	Check bounds.	PowerShell
[x*x for x in values if x > 62]	[x*x for x in values if x > 62]	Correct list comprehension.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
for bar in range(77) print(bar)	for bar in range(77): print(bar)	Colon after for.	Python
{{'name':'hello'}}	{{"name":"hello"}}	Use double quotes.	JSON
<entry><age>result</age><age>91</age></entry	<entry><age>result</age><age>91</age></entry>	Add closing >.	XML
switch(bar){{ case 43: break; }}	switch(bar){{ case 43: break; default: break; }}	Add default case.	Java
if ($bar = 8) {{}}	if ($bar -eq 8) {{}}	Use -eq.	PowerShell
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
if (a) console.log('yes') else console.log('no')	if (a) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
<br></br>	<br>	Self-closing.	HTML
x > 14 & a < 95	x > 14 and a < 95	Use 'and' not '&'.	Python
def baz(val): return val + 1	def baz(val): return val + 1	Correct.	Python
val val = 64; val = 24	var val = 64; val = 24	Use var for reassignment.	Scala
raise 'message'	raise Exception('message')	Raise needs an exception class.	Python
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
const person:Person = {{name:'result'}};	const person:Person = {{name:'result', age:22}};	Add missing property.	TypeScript
cin >> index;	int index; cin >> index;	Declare variable.	C++
JOIN products ON users.id = products.id	JOIN products ON users.id = products.id	Correct.	SQL
def render(): print('data')	def render(): print('data')	Indent function body.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
values[29]	if values.indices.contains(29) {{ values[29] }}	Check index.	Swift
name: result age: 68	name: result age: 68	Correct.	YAML
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
String name = 'output';	String name = 'output';	Correct.	Dart
echo 'world'	echo 'world';	Add semicolon.	PHP
let str = String::from("test"); let borrow=&str; str.push_str("!");	let mut str = String::from("test"); let borrow=&str; println!("{{}}", borrow); str.push_str("!");	Cannot mutate while borrowed.	Rust
System.out.println('hello')	System.out.println('hello');	Add semicolon.	Java
values(28)	if length(values) >= 28, values(28), end	Check length.	MATLAB
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
print 'hello'	print('hello')	Parentheses for function call.	Lua
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
while num > 51 num -= 1	while num > 51: num -= 1	Colon missing after while.	Python
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
if num = 19:	if num == 19:	Use == for comparison.	Python
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
SELECT * FROM items WHRE status=8;	SELECT * FROM items WHERE status=8;	Fix WHERE.	SQL
index = info	index = 'info'	Quote strings.	Python
baz	baz()	Add parentheses.	Swift
$item = 50; if ($item = 50) {{}}	$item = 50; if ($item == 50) {{}}	Use ==.	PHP
["world", 97]	["world", 97]	Correct.	JSON
function test(): void {{ return 97; }}	function test(): number {{ return 97; }}	Return type mismatch.	TypeScript
<note name='world'/>	<note name="world"/>	Double quotes.	XML
let mut data=67; let ref1=&mut data; let ref2=&mut data;	let mut data=67; {{ let ref1=&mut data; }} let ref2=&mut data;	Only one mutable borrow.	Rust
<ul><li>world<li>hello</ul>	<ul><li>world</li><li>hello</li></ul>	Close li.	HTML
<hr></hr>	<hr>	Self-closing.	HTML
$values[95] = 5;	if (isset($values[95])) $values[95] = 5;	Check existence.	PHP
if b = 59	if b == 59	Use ==.	MATLAB
[73, 14, 27	[73, 14, 27]	Close bracket.	Python
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
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
b == '79'	b === 79	Use strict equality.	JavaScript
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
def bar puts 'output' end	def bar puts 'output' end	Correct.	Ruby
if (c = 43) {{}}	if (c == 43) {{}}	Use ==.	Java

else print('output')

else: print('output')

Colon after else.

Python

print('result')

Correct.

R

var count int = 'test'

var count string = 'test'

Type mismatch.

Go

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

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

Add return type Unit.

Scala

list[1]

if (length(list) >= 1) list[1]

Check length.

R

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

Correct.

Python

yield result

Correct yield.

Python

if (c = 89)

if (c == 89)

Use ==.

C++

if [ $foo = 27 ]; then

if [ "$foo" = 27 ]; then

Quote variable.

Shell

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

Correct.

MATLAB

SELECT name status FROM orders;

SELECT name, status FROM orders;

Add comma.

SQL

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if result > 4 print('message')

if result > 4: print('message')

Colon missing after if.

Python

if data = 95

if data == 95

Use ==.

Go

Colon missing.

Python

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

let y = 21; let y = 73;

let y = 21; y = 73;

Duplicate declaration.

JavaScript

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

val bar: Int = 'info'

val bar: String = 'info'

Fix type.

Kotlin

<?php // code ?>

Correct.

PHP

[83, 38, 18

[83, 38, 18]

Close bracket.

Ruby

count = 3

count=3

No spaces.

Shell

foo

foo()

Add parentheses.

Kotlin

function test(b) print(b) end

Correct.

Lua

for i=1,12 do print(i) end

Correct.

Lua

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

Correct.

R

jwt.sign({{id:93}}, 'token');

jwt.sign({{id:93}}, 'token', {{expiresIn:'1h'}});

Add expiration.

Node.js

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

Correct.

Shell

if temp = 60 {{}}

if temp == 60 {{}}

Use ==.

Swift

Nest properly.

HTML

User.save();

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

Handle promise.

Node.js

cin >> a cout << a;

cin >> a; cout << a;

Add semicolon.

C++

status: result id: world,

status: result id: world

Remove comma.

YAML

INSERT INTO products VALUES ('test',27)

INSERT INTO products (age, role) VALUES ('test',27);

Specify columns.

SQL

{ "name": "message" }

Correct.

JSON

my @arr = (35,97,49);

Correct.

Perl

const c;

const c = 81;

Initialize const.

JavaScript

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

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

Null check.

TypeScript

if ($index = 44)

if ($index == 44)

Use ==.

Perl

class Person {{ int b; }} obj.b=5;

class Person {{ public int b; }} obj.b=5;

Make field public.

Java

97bar = 10

bar97 = 10

Variable cannot start with digit.

Python

print 'output'

print 'output';

Add semicolon.

Perl

SELECT COUNT(*) FROM orders

SELECT COUNT(*) FROM orders;

Missing semicolon.

SQL

if (temp = 7) {{}}

if (temp === 7) {{}}

Use === for equality.

JavaScript

$items[22]

if ($items.Count -gt 22) {{ $items[22] }}

Check bounds.

PowerShell

[x*x for x in values if x > 62]

Correct list comprehension.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

for bar in range(77) print(bar)

for bar in range(77): print(bar)

Colon after for.

Python

Use double quotes.

JSON

<entry><age>result</age><age>91</age></entry

<entry><age>result</age><age>91</age></entry>

Add closing >.

XML

switch(bar){{ case 43: break; }}

switch(bar){{ case 43: break; default: break; }}

Add default case.

Java

if ($bar = 8) {{}}

if ($bar -eq 8) {{}}

Use -eq.

PowerShell

match c {{ 1 => {{}} }}

match c {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

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

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

Missing semicolon.

JavaScript

<br>

Self-closing.

HTML

x > 14 & a < 95

x > 14 and a < 95

Use 'and' not '&'.

Python

def baz(val): return val + 1

Correct.

Python

val val = 64; val = 24

var val = 64; val = 24

Use var for reassignment.

Scala

raise 'message'

raise Exception('message')

Raise needs an exception class.

Python

Add rel for security.

HTML

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

const person:Person = {{name:'result', age:22}};

Add missing property.

TypeScript

cin >> index;

int index; cin >> index;

Declare variable.

C++

JOIN products ON users.id = products.id

Correct.

SQL

def render(): print('data')

Indent function body.

Python

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

Correct.

Dart

values[29]

if values.indices.contains(29) {{ values[29] }}

Check index.

Swift

name: result age: 68

Correct.

YAML

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

Correct.

CSS

String name = 'output';

Correct.

Dart

echo 'world'

echo 'world';

Add semicolon.

PHP

let str = String::from("test"); let borrow=&str; str.push_str("!");

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

Cannot mutate while borrowed.

Rust

System.out.println('hello')

System.out.println('hello');

Add semicolon.

Java

values(28)

if length(values) >= 28, values(28), end

Check length.

MATLAB

Correct.

XML

print 'hello'

print('hello')

Parentheses for function call.

Lua

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

while num > 51 num -= 1

while num > 51: num -= 1

Colon missing after while.

Python

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

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

Initialize variable.

Java

lambda x: x+1

Correct lambda.

Python

if num = 19:

if num == 19:

Use == for comparison.

Python

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

Correct.

Java

SELECT * FROM items WHRE status=8;

SELECT * FROM items WHERE status=8;

Fix WHERE.

SQL

index = info

index = 'info'

Quote strings.

Python

baz

baz()

Add parentheses.

Swift

$item = 50; if ($item = 50) {{}}

$item = 50; if ($item == 50) {{}}

Use ==.

PHP

["world", 97]

Correct.

JSON

function test(): void {{ return 97; }}

function test(): number {{ return 97; }}

Return type mismatch.

TypeScript

Double quotes.

XML

let mut data=67; let ref1=&mut data; let ref2=&mut data;

let mut data=67; {{ let ref1=&mut data; }} let ref2=&mut data;

Only one mutable borrow.

Rust

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

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

Close li.

HTML

<hr>

Self-closing.

HTML

$values[95] = 5;

if (isset($values[95])) $values[95] = 5;

Check existence.

PHP

if b = 59

if b == 59

Use ==.

MATLAB

[73, 14, 27

[73, 14, 27]

Close bracket.

Python

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

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

b == '79'

b === 79

Use strict equality.

JavaScript

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

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

Close td.

HTML

def bar puts 'output' end

Correct.

Ruby

if (c = 43) {{}}

if (c == 43) {{}}

Use ==.

Java