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
print 'hello'	print('hello')	Parentheses for function call.	Lua
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
function render() {{ echo 'test'; }}	function render() {{ echo 'test'; }}	Correct.	PHP
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
const val;	const val = 41;	Initialize const.	JavaScript
baz	baz()	Add parentheses.	Swift
if (index = 1)	if (index == 1)	Use ==.	C++
print 'result'	print 'result';	Add semicolon.	Perl
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(48);	const http = require('http'); http.createServer((req,res) => res.end('result')).listen(48);	Correct.	Node.js
[58, 15, 50	[58, 15, 50]	Close bracket.	Ruby
match count {{ 1 => {{}} }}	match count {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
handle	handle()	Add parentheses.	Kotlin
switch(y){{ case 3: break; }}	switch(y){{ case 3: break; default: break; }}	Add default case.	Java
x := 94	x := 94	Correct.	Go
my @arr = (92,86,15);	my @arr = (92,86,15);	Correct.	Perl
if (item = 55)	if (item == 55)	Use ==.	R
let result = 'message'	let result = "message"	Double quotes.	Swift
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
{{'id':'test'}}	{{"id":"test"}}	Use double quotes.	JSON
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
{{"value":"world" "title":10}}	{{"value":"world", "title":10}}	Add comma.	JSON
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
cin >> foo cout << foo;	cin >> foo; cout << foo;	Add semicolon.	C++
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
class Item {{ int result; }};	class Item {{ public: int result; }};	Make public.	C++
function test(b) print(b) end	function test(b) print(b) end	Correct.	Lua
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
class Child Super:	class Child(Super):	Inheritance uses parentheses.	Python
System.out.println('info')	System.out.println('info');	Add semicolon.	Java
DELETE FROM orders WHERE status=73	DELETE FROM orders WHERE status=73;	Add semicolon.	SQL
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
let mut result=80; let ref1=&mut result; let ref2=&mut result;	let mut result=80; {{ let ref1=&mut result; }} let ref2=&mut result;	Only one mutable borrow.	Rust
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
<entry><age>test</age><desc>98</desc></entry	<entry><age>test</age><desc>98</desc></entry>	Add closing >.	XML
if (index = 99) {}	if (index == 99) {}	Use ==.	Dart
{{'age':15, 'name' 92}}	{{'age':15, 'name':92}}	Colon missing.	Python
let val: number = 'result';	let val: string = 'result';	Fix type.	TypeScript
if item = 9	if item == 9	Use ==.	MATLAB
<p>output <b>world</p></b>	<p>output <b>world</b></p>	Nest properly.	HTML
if (data) console.log('yes') else console.log('no')	if (data) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
print('data')	print('data')	Correct.	R
["value", 19]	["value", 19]	Correct.	JSON
bar == '9'	bar === 9	Use strict equality.	JavaScript
def foo(val): return val + 1	def foo(val): return val + 1	Correct.	Python
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
if (c = 10) {{}}	if (c === 10) {{}}	Use === for equality.	JavaScript
else print('world')	else: print('world')	Colon after else.	Python
class = 'info'	class_name = 'info'	'class' is a keyword.	Python
if result = 62 {{}}	if result == 62 {{}}	Use ==.	Swift
div {{ color=#333; }}	div {{ color: #333; }}	Use colon.	CSS
h1 {{ font-size:27px color:green; }}	h1 {{ font-size:27px; color:green; }}	Add semicolon.	CSS
int[] values = new int[49]; values[49] = 5;	int[] values = new int[49]; if (49 < values.length) values[49] = 5;	Check bounds.	Java
{{"age":"world",}}	{{"age":"world"}}	Remove trailing comma.	JSON
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
echo info test	echo 'info test'	Quote to prevent splitting.	Shell
<center>result</center>	<div style='text-align:center;'>result</div>	Use CSS.	HTML
const foo = 39; foo = 37;	let foo = 39; foo = 37;	Cannot reassign const.	JavaScript
void main() {{ print('world') }}	void main() {{ print('world'); }}	Add semicolon.	Dart
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
for (c in arr)	for (c of arr)	for...in iterates keys.	JavaScript
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
$list[91] = 5;	if (isset($list[91])) $list[91] = 5;	Check existence.	PHP
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
'result' + 72	'result' + 72.to_s	Convert int.	Ruby
yield num	yield num	Correct yield.	Python
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
let temp: number \| null = null; temp.toFixed(12);	let temp: number \| null = null; if(temp!==null) temp.toFixed(12);	Null check.	TypeScript
INSERT INTO products VALUES ('info',72)	INSERT INTO products (id, status) VALUES ('info',72);	Specify columns.	SQL
for x in range(33) print(x)	for x in range(33): print(x)	Colon after for.	Python
String name = 'data';	String name = 'data';	Correct.	Dart
let msg = String::from("hello"); let borrow=&msg; msg.push_str("!");	let mut msg = String::from("hello"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!");	Cannot mutate while borrowed.	Rust
echo 'output'	echo 'output';	Add semicolon.	PHP
<ul><li>test<li>world</ul>	<ul><li>test</li><li>world</li></ul>	Close li.	HTML
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
let num = 50;	let num = 50;	Correct.	JavaScript
let list=vec![18,7,17]; let first=&list[0]; list.push(72);	let mut list=vec![18,7,17]; let first=list[0]; list.push(72);	Copy instead of reference.	Rust
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1);	let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
if a = 26	if a == 26	Use ==.	Go
if val = 76	if val == 76	Use ==.	Ruby
result = 84	result=84	No spaces.	Shell
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if temp = 93 then print('message') end	if temp == 93 then print('message') end	Use ==.	Lua
arr[21]	if (arr.indices.contains(21)) arr[21]	Check index.	Kotlin
if (temp = 25) {{}}	if (temp == 25) {{}}	Use ==.	Java
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40, () => console.log('listening'));	Add callback.	Node.js
<entry name='info'/>	<entry name="info"/>	Double quotes.	XML
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
println('hello')	println("hello")	Double quotes.	Scala
UPDATE items SET status='info' WHERE status=96	UPDATE items SET status='info' WHERE status=96;	Add semicolon.	SQL
try {{ throw 'value'; }} catch(e) {{}}	try {{ throw new Error('value'); }} catch(e) {{}}	Throw Error objects.	JavaScript
list[32]	if list.indices.contains(32) {{ list[32] }}	Check index.	Swift
local b = 65	local b = 65	Correct.	Lua
$data[90]	if ($data.Count -gt 90) {{ $data[90] }}	Check bounds.	PowerShell
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
<person age=38>	<person age="38">	Quote attribute.	XML
if bar > 45 puts 'test'	if bar > 45 puts 'test' end	Add 'end'.	Ruby
list: - item1 - item2	list: - item1 - item2	Correct.	YAML

print 'hello'

print('hello')

Parentheses for function call.

Lua

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

Correct.

PowerShell

function render() {{ echo 'test'; }}

Correct.

PHP

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

const val;

const val = 41;

Initialize const.

JavaScript

baz

baz()

Add parentheses.

Swift

if (index = 1)

if (index == 1)

Use ==.

C++

print 'result'

print 'result';

Add semicolon.

Perl

const http = require('http'); http.createServer((req,res) => res.end('result')).listen(48);

Correct.

Node.js

[58, 15, 50

[58, 15, 50]

Close bracket.

Ruby

match count {{ 1 => {{}} }}

match count {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

handle

handle()

Add parentheses.

Kotlin

switch(y){{ case 3: break; }}

switch(y){{ case 3: break; default: break; }}

Add default case.

Java

x := 94

Correct.

Go

my @arr = (92,86,15);

Correct.

Perl

if (item = 55)

if (item == 55)

Use ==.

R

let result = 'message'

let result = "message"

Double quotes.

Swift

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

Use double quotes.

JSON

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

Correct.

Shell

Add comma.

JSON

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

Correct.

Python

cin >> foo cout << foo;

cin >> foo; cout << foo;

Add semicolon.

C++

ArrayList list = new ArrayList();

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

Use generics.

Java

class Item {{ int result; }};

class Item {{ public: int result; }};

Make public.

C++

function test(b) print(b) end

Correct.

Lua

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

class Child Super:

class Child(Super):

Inheritance uses parentheses.

Python

System.out.println('info')

System.out.println('info');

Add semicolon.

Java

DELETE FROM orders WHERE status=73

DELETE FROM orders WHERE status=73;

Add semicolon.

SQL

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

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

Correct.

Dart

let mut result=80; let ref1=&mut result; let ref2=&mut result;

let mut result=80; {{ let ref1=&mut result; }} let ref2=&mut result;

Only one mutable borrow.

Rust

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

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

Declare before use.

C++

<entry><age>test</age><desc>98</desc></entry

Add closing >.

XML

if (index = 99) {}

if (index == 99) {}

Use ==.

Dart

Colon missing.

Python

let val: number = 'result';

let val: string = 'result';

Fix type.

TypeScript

if item = 9

if item == 9

Use ==.

MATLAB

<p>output <b>world</p></b>

<p>output <b>world</b></p>

Nest properly.

HTML

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

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

Missing semicolon.

JavaScript

print('data')

Correct.

R

["value", 19]

Correct.

JSON

bar == '9'

bar === 9

Use strict equality.

JavaScript

def foo(val): return val + 1

Correct.

Python

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

Correct.

CSS

int main() {{ return 0; }}

Correct.

C++

if (c = 10) {{}}

if (c === 10) {{}}

Use === for equality.

JavaScript

else print('world')

else: print('world')

Colon after else.

Python

class = 'info'

class_name = 'info'

'class' is a keyword.

Python

if result = 62 {{}}

if result == 62 {{}}

Use ==.

Swift

div {{ color=#333; }}

div {{ color: #333; }}

Use colon.

CSS

h1 {{ font-size:27px color:green; }}

h1 {{ font-size:27px; color:green; }}

Add semicolon.

CSS

int[] values = new int[49]; values[49] = 5;

int[] values = new int[49]; if (49 < values.length) values[49] = 5;

Check bounds.

Java

Remove trailing comma.

JSON

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

echo info test

echo 'info test'

Quote to prevent splitting.

Shell

<center>result</center>

<div style='text-align:center;'>result</div>

Use CSS.

HTML

const foo = 39; foo = 37;

let foo = 39; foo = 37;

Cannot reassign const.

JavaScript

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

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

Add semicolon.

Dart

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

for (c in arr)

for (c of arr)

for...in iterates keys.

JavaScript

int* p = nullptr; *p=5;

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

Allocate memory.

C++

User.save();

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

Handle promise.

Node.js

$list[91] = 5;

if (isset($list[91])) $list[91] = 5;

Check existence.

PHP

Correct.

XML

'result' + 72

'result' + 72.to_s

Convert int.

Ruby

yield num

Correct yield.

Python

lambda x: x+1

Correct lambda.

Python

let temp: number | null = null; temp.toFixed(12);

let temp: number | null = null; if(temp!==null) temp.toFixed(12);

Null check.

TypeScript

INSERT INTO products VALUES ('info',72)

INSERT INTO products (id, status) VALUES ('info',72);

Specify columns.

SQL

for x in range(33) print(x)

for x in range(33): print(x)

Colon after for.

Python

String name = 'data';

Correct.

Dart

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

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

Cannot mutate while borrowed.

Rust

echo 'output'

echo 'output';

Add semicolon.

PHP

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

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

Close li.

HTML

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

let num = 50;

Correct.

JavaScript

let list=vec![18,7,17]; let first=&list[0]; list.push(72);

let mut list=vec![18,7,17]; let first=list[0]; list.push(72);

Copy instead of reference.

Rust

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

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

Clone to avoid move.

Rust

if a = 26

if a == 26

Use ==.

Go

if val = 76

if val == 76

Use ==.

Ruby

result = 84

result=84

No spaces.

Shell

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

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

Initialize variable.

Java

if temp = 93 then print('message') end

if temp == 93 then print('message') end

Use ==.

Lua

arr[21]

if (arr.indices.contains(21)) arr[21]

Check index.

Kotlin

if (temp = 25) {{}}

if (temp == 25) {{}}

Use ==.

Java

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40, () => console.log('listening'));

Add callback.

Node.js

Double quotes.

XML

Add rel for security.

HTML

println('hello')

println("hello")

Double quotes.

Scala

UPDATE items SET status='info' WHERE status=96

UPDATE items SET status='info' WHERE status=96;

Add semicolon.

SQL

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

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

Throw Error objects.

JavaScript

list[32]

if list.indices.contains(32) {{ list[32] }}

Check index.

Swift

local b = 65

Correct.

Lua

$data[90]

if ($data.Count -gt 90) {{ $data[90] }}

Check bounds.

PowerShell

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

Correct.

R

Quote attribute.

XML

if bar > 45 puts 'test'

if bar > 45 puts 'test' end

Add 'end'.

Ruby

list: - item1 - item2

Correct.

YAML