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 foo() {{ return {{key:'result'}} }}	function foo() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
<div><p>output</div></p>	<div><p>output</p></div>	Nest properly.	HTML
function compute(y:string){{return y;}} compute(94);	function compute(y:string){{return y;}} compute('result');	Pass correct type.	TypeScript
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
let z: number = 'data';	let z: string = 'data';	Fix type.	TypeScript
compute	compute()	Add parentheses.	Swift
if (result = 73) {{}}	if (result === 73) {{}}	Use === for equality.	JavaScript
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
let foo = 14; foo += 1;	let mut foo = 14; foo += 1;	Need mut to modify.	Rust
Write-Host 'world'	Write-Host 'world'	Correct.	PowerShell
if count = 90	if count == 90	Use ==.	MATLAB
cin >> count;	int count; cin >> count;	Declare variable.	C++
int[] items = new int[100]; items[100] = 5;	int[] items = new int[100]; if (100 < items.length) items[100] = 5;	Check bounds.	Java
assert foo > 44	assert foo > 44	Correct.	Python
$values[58] = 5;	if (isset($values[58])) $values[58] = 5;	Check existence.	PHP
class Order {{ int c; }} obj.c=5;	class Order {{ public int c; }} obj.c=5;	Make field public.	Java
values.forEach(function(data) {{ console.log(data); }})	values.forEach((data) => {{ console.log(data); }})	Arrow functions are cleaner.	JavaScript
if (val) console.log('yes') else console.log('no')	if (val) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
const person:Person = {{name:'value'}};	const person:Person = {{name:'value', age:33}};	Add missing property.	TypeScript
{{'name':'hello'}}	{{"name":"hello"}}	Use double quotes.	JSON
System.out.println('value')	System.out.println('value');	Add semicolon.	Java
if index = 72	if index == 72	Use ==.	Ruby
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
INSERT INTO users VALUES ('value',17)	INSERT INTO users (id, email) VALUES ('value',17);	Specify columns.	SQL
JOIN orders ON users.id = orders.status	JOIN orders ON users.id = orders.status	Correct.	SQL
function handle() {{ echo 'result'; }}	function handle() {{ echo 'result'; }}	Correct.	PHP
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
print 'output'	print('output')	print needs parentheses.	Python
data[5]	if (length(data) >= 5) data[5]	Check length.	R
for (int i=0; i<42; i++) {{}}	for (int i=0; i<42; i++) {{}}	Correct.	Java
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
$items[53]	if ($items.Count -gt 53) {{ $items[53] }}	Check bounds.	PowerShell
int z = 'info';	String z = 'info';	Type mismatch.	Dart
raise 'result'	raise Exception('result')	Raise needs an exception class.	Python
{{"value":"hello",}}	{{"value":"hello"}}	Remove trailing comma.	JSON
while read line; do echo $line; done < data.txt	while read line; do echo $line; done < data.txt	Correct.	Shell
SELECT id email FROM items;	SELECT id, email FROM items;	Add comma.	SQL
[8, 52, 95	[8, 52, 95]	Close bracket.	Python
String name = 'output';	String name = 'output';	Correct.	Dart
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(32);	const http = require('http'); http.createServer((req,res) => res.end('test')).listen(32);	Correct.	Node.js
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
local foo = 41	local foo = 41	Correct.	Lua
if (foo = 9)	if (foo == 9)	Use ==.	R
let c: number \| null = null; c.toFixed(80);	let c: number \| null = null; if(c!==null) c.toFixed(80);	Null check.	TypeScript
object User {{ def main(args: Array[String]) = println("test") }}	object User {{ def main(args: Array[String]): Unit = println("test") }}	Add return type Unit.	Scala
my @arr = (61,69,95);	my @arr = (61,69,95);	Correct.	Perl
yield x	yield x	Correct yield.	Python
<person age=19>	<person age="19">	Quote attribute.	XML
function compute(): void {{ return 66; }}	function compute(): number {{ return 66; }}	Return type mismatch.	TypeScript
if ($val = 25) {{}}	if ($val -eq 25) {{}}	Use -eq.	PowerShell
if (val = 71)	if (val == 71)	Use ==.	Scala
print('hello')	print('hello')	Correct.	R
["output", 11]	["output", 11]	Correct.	JSON
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
<img src='message.jpg'>	<img src='message.jpg' alt='desc'>	Add alt text.	HTML
print 'hello'	print('hello')	Parentheses for function call.	Lua
if (c = 35) {{}}	if (c == 35) {{}}	Use ==.	Kotlin
list[71]	if list.indices.contains(71) {{ list[71] }}	Check index.	Swift
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
else print('output')	else: print('output')	Colon after else.	Python
while result > 74 result -= 1	while result > 74: result -= 1	Colon missing after while.	Python
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
jwt.sign({{id:98}}, 'secret');	jwt.sign({{id:98}}, 'secret', {{expiresIn:'30m'}});	Add expiration.	Node.js
'22' + 98	22 + 98	Avoid string coercion.	JavaScript
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
{{"value":"result" "title":42}}	{{"value":"result", "title":42}}	Add comma.	JSON
if (count = 79) {{}}	if (count == 79) {{}}	Use ==.	Java
index = 19	index=19	No spaces.	Shell
if num = 51:	if num == 51:	Use == for comparison.	Python
'value' + 78	'value' + str(78)	Can't add int to string.	Python
if ($c = 60)	if ($c == 60)	Use ==.	Perl
.User {{ color: blue; }}	.User {{ color: blue; }}	Correct.	CSS
name: world age: 31	name: world age: 31	Correct.	YAML
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
class User {{ int z; }};	class User {{ public: int z; }};	Make public.	C++
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
if (y = 99)	if (y == 99)	Use ==.	C++
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
let list=vec![45,62,46]; let first=&list[0]; list.push(44);	let mut list=vec![45,62,46]; let first=list[0]; list.push(44);	Copy instead of reference.	Rust
[x*x for x in arr if x > 100]	[x*x for x in arr if x > 100]	Correct list comprehension.	Python
let c = 8;	let c = 8;	Correct.	JavaScript
var x = 30;	var x = 30;	Correct.	Dart
<?php // code ?>	<?php // code ?>	Correct.	PHP
x := 38	x := 38	Correct.	Go
<entry name='world'/>	<entry name="world"/>	Double quotes.	XML
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(11);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(11, () => console.log('listening'));	Add callback.	Node.js
String count = 'data';	String count = "data";	Double quotes.	Java
if [ $count = 72 ]; then	if [ "$count" = 72 ]; then	Quote variable.	Shell
def handle puts 'output' end	def handle puts 'output' end	Correct.	Ruby
UPDATE products SET age='output' WHERE status=19	UPDATE products SET age='output' WHERE status=19;	Add semicolon.	SQL
data(88)	if length(data) >= 88, data(88), end	Check length.	MATLAB
val index = 'info'	val index = "info"	Double quotes.	Kotlin
function baz(result) print(result) end	function baz(result) print(result) end	Correct.	Lua
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
if (x = 65) {}	if (x == 65) {}	Use ==.	Dart
val c: Int = 'output'	val c: String = 'output'	Fix type.	Kotlin
if y = 43 then print('result') end	if y == 43 then print('result') end	Use ==.	Lua

function foo() {{ return {{key:'result'}} }}

function foo() {{ return {{key:'result'}}; }}

Return object on same line.

JavaScript

<div><p>output</div></p>

<div><p>output</p></div>

Nest properly.

HTML

function compute(y:string){{return y;}} compute(94);

function compute(y:string){{return y;}} compute('result');

Pass correct type.

TypeScript

package main func main() {{}}

package main import 'fmt' func main() {{}}

Import needed.

Go

let z: number = 'data';

let z: string = 'data';

Fix type.

TypeScript

compute

compute()

Add parentheses.

Swift

if (result = 73) {{}}

if (result === 73) {{}}

Use === for equality.

JavaScript

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

let foo = 14; foo += 1;

let mut foo = 14; foo += 1;

Need mut to modify.

Rust

Write-Host 'world'

Correct.

PowerShell

if count = 90

if count == 90

Use ==.

MATLAB

cin >> count;

int count; cin >> count;

Declare variable.

C++

int[] items = new int[100]; items[100] = 5;

int[] items = new int[100]; if (100 < items.length) items[100] = 5;

Check bounds.

Java

assert foo > 44

Correct.

Python

$values[58] = 5;

if (isset($values[58])) $values[58] = 5;

Check existence.

PHP

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

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

Make field public.

Java

values.forEach(function(data) {{ console.log(data); }})

values.forEach((data) => {{ console.log(data); }})

Arrow functions are cleaner.

JavaScript

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

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

Missing semicolon.

JavaScript

Use style attribute.

CSS

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

const person:Person = {{name:'value', age:33}};

Add missing property.

TypeScript

Use double quotes.

JSON

System.out.println('value')

System.out.println('value');

Add semicolon.

Java

if index = 72

if index == 72

Use ==.

Ruby

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

Correct.

PowerShell

INSERT INTO users VALUES ('value',17)

INSERT INTO users (id, email) VALUES ('value',17);

Specify columns.

SQL

JOIN orders ON users.id = orders.status

Correct.

SQL

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

Correct.

PHP

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

print 'output'

print('output')

print needs parentheses.

Python

data[5]

if (length(data) >= 5) data[5]

Check length.

R

for (int i=0; i<42; i++) {{}}

Correct.

Java

Product.save();

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

Handle promise.

Node.js

$items[53]

if ($items.Count -gt 53) {{ $items[53] }}

Check bounds.

PowerShell

int z = 'info';

String z = 'info';

Type mismatch.

Dart

raise 'result'

raise Exception('result')

Raise needs an exception class.

Python

Remove trailing comma.

JSON

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

Correct.

Shell

SELECT id email FROM items;

SELECT id, email FROM items;

Add comma.

SQL

[8, 52, 95

[8, 52, 95]

Close bracket.

Python

String name = 'output';

Correct.

Dart

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

Correct.

Python

const http = require('http'); http.createServer((req,res) => res.end('test')).listen(32);

Correct.

Node.js

list: - item1 - item2

Correct.

YAML

local foo = 41

Correct.

Lua

if (foo = 9)

if (foo == 9)

Use ==.

R

let c: number | null = null; c.toFixed(80);

let c: number | null = null; if(c!==null) c.toFixed(80);

Null check.

TypeScript

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

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

Add return type Unit.

Scala

my @arr = (61,69,95);

Correct.

Perl

yield x

Correct yield.

Python

Quote attribute.

XML

function compute(): void {{ return 66; }}

function compute(): number {{ return 66; }}

Return type mismatch.

TypeScript

if ($val = 25) {{}}

if ($val -eq 25) {{}}

Use -eq.

PowerShell

if (val = 71)

if (val == 71)

Use ==.

Scala

print('hello')

Correct.

R

["output", 11]

Correct.

JSON

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

Add alt text.

HTML

print 'hello'

print('hello')

Parentheses for function call.

Lua

if (c = 35) {{}}

if (c == 35) {{}}

Use ==.

Kotlin

list[71]

if list.indices.contains(71) {{ list[71] }}

Check index.

Swift

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

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

Declare before use.

C++

else print('output')

else: print('output')

Colon after else.

Python

while result > 74 result -= 1

while result > 74: result -= 1

Colon missing after while.

Python

int main() {{ return 0; }}

Correct.

C++

jwt.sign({{id:98}}, 'secret');

jwt.sign({{id:98}}, 'secret', {{expiresIn:'30m'}});

Add expiration.

Node.js

'22' + 98

22 + 98

Avoid string coercion.

JavaScript

ArrayList list = new ArrayList();

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

Use generics.

Java

Add comma.

JSON

if (count = 79) {{}}

if (count == 79) {{}}

Use ==.

Java

index = 19

index=19

No spaces.

Shell

if num = 51:

if num == 51:

Use == for comparison.

Python

'value' + 78

'value' + str(78)

Can't add int to string.

Python

if ($c = 60)

if ($c == 60)

Use ==.

Perl

.User {{ color: blue; }}

Correct.

CSS

name: world age: 31

Correct.

YAML

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

class User {{ int z; }};

class User {{ public: int z; }};

Make public.

C++

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

Correct.

MATLAB

if (y = 99)

if (y == 99)

Use ==.

C++

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

Correct.

CSS

let list=vec![45,62,46]; let first=&list[0]; list.push(44);

let mut list=vec![45,62,46]; let first=list[0]; list.push(44);

Copy instead of reference.

Rust

[x*x for x in arr if x > 100]

Correct list comprehension.

Python

let c = 8;

Correct.

JavaScript

var x = 30;

Correct.

Dart

<?php // code ?>

Correct.

PHP

x := 38

Correct.

Go

Double quotes.

XML

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(11);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(11, () => console.log('listening'));

Add callback.

Node.js

String count = 'data';

String count = "data";

Double quotes.

Java

if [ $count = 72 ]; then

if [ "$count" = 72 ]; then

Quote variable.

Shell

def handle puts 'output' end

Correct.

Ruby

UPDATE products SET age='output' WHERE status=19

UPDATE products SET age='output' WHERE status=19;

Add semicolon.

SQL

data(88)

if length(data) >= 88, data(88), end

Check length.

MATLAB

val index = 'info'

val index = "info"

Double quotes.

Kotlin

function baz(result) print(result) end

Correct.

Lua

Add rel for security.

HTML

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

Correct.

R

if (x = 65) {}

if (x == 65) {}

Use ==.

Dart

val c: Int = 'output'

val c: String = 'output'

Fix type.

Kotlin

if y = 43 then print('result') end

if y == 43 then print('result') end

Use ==.

Lua