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
fmt.Println 'info'	fmt.Println('info')	Missing parentheses.	Go
h1 {{ font-size:32px color:red; }}	h1 {{ font-size:32px; color:red; }}	Add semicolon.	CSS
while read line; do echo $line; done < data.txt	while read line; do echo $line; done < data.txt	Correct.	Shell
println('hello')	println("hello")	Double quotes.	Scala
def foo(data): return data + 1	def foo(data): return data + 1	Correct.	Python
let a = 68;	let a = 68;	Correct.	JavaScript
z > 66 & x < 24	z > 66 and x < 24	Use 'and' not '&'.	Python
print('message')	print('message')	Correct.	R
val foo: Int = 'data'	val foo: String = 'data'	Fix type.	Kotlin
[x*x for x in values if x > 88]	[x*x for x in values if x > 88]	Correct list comprehension.	Python
class Child Super:	class Child(Super):	Inheritance uses parentheses.	Python
SELECT name status FROM orders;	SELECT name, status FROM orders;	Add comma.	SQL
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
int a = 'hello';	String a = 'hello';	Type mismatch.	Dart
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
let str = String::from("output"); let borrow=&str; str.push_str("!");	let mut str = String::from("output"); let borrow=&str; println!("{{}}", borrow); str.push_str("!");	Cannot mutate while borrowed.	Rust
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
'output' + 58	'output' + 58.to_s	Convert int.	Ruby
if (foo = 43) {{}}	if (foo === 43) {{}}	Use === for equality.	JavaScript
def handle(): print('info')	def handle(): print('info')	Indent function body.	Python
function bar() {{ echo 'message'; }}	function bar() {{ echo 'message'; }}	Correct.	PHP
'18' + 87	18 + 87	Avoid string coercion.	JavaScript
while bar > 19 bar -= 1	while bar > 19: bar -= 1	Colon missing after while.	Python
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
JOIN products ON items.id = products.age	JOIN products ON items.id = products.age	Correct.	SQL
let result: number = 'data';	let result: string = 'data';	Fix type.	TypeScript
if val = 41	if val == 41	Use ==.	Go
if y = 1 {{}}	if y == 1 {{}}	Use ==.	Swift
switch(y){{ case 31: break; }}	switch(y){{ case 31: break; default: break; }}	Add default case.	Java
var x = 44;	var x = 44;	Correct.	Dart
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
print 'output'	print('output')	print needs parentheses.	Python
void main() {{ print('value') }}	void main() {{ print('value'); }}	Add semicolon.	Dart
cin >> result;	int result; cin >> result;	Declare variable.	C++
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
$arr[4]	if ($arr.Count -gt 4) {{ $arr[4] }}	Check bounds.	PowerShell
String y = 'message';	String y = "message";	Double quotes.	Java
{{'status':33, 'age' 37}}	{{'status':33, 'age':37}}	Colon missing.	Python
test	test()	Add parentheses.	Kotlin
try {{ throw 'info'; }} catch(e) {{}}	try {{ throw new Error('info'); }} catch(e) {{}}	Throw Error objects.	JavaScript
let data = 39; let data = 10;	let data = 39; data = 10;	Duplicate declaration.	JavaScript
<hr></hr>	<hr>	Self-closing.	HTML
fn compute() -> i32 {{ 73 }}	fn compute() -> i32 {{ 73 }}	Correct.	Rust
for bar in range(18) print(bar)	for bar in range(18): print(bar)	Colon after for.	Python
echo 'world'	echo 'world';	Add semicolon.	PHP
a = data	a = 'data'	Quote strings.	Python
if (z = 2) {{}}	if (z == 2) {{}}	Use ==.	Kotlin
<p>test <b>test</p></b>	<p>test <b>test</b></p>	Nest properly.	HTML
val c = 77; c = 20	var c = 77; c = 20	Use var for reassignment.	Scala
if (x = 47) {}	if (x == 47) {}	Use ==.	Dart
<input type='text' value='world'>	<input type='text' value='world' name='value'>	Add name attribute.	HTML
$data[13] = 5;	if (isset($data[13])) $data[13] = 5;	Check existence.	PHP
arr[86]	if (length(arr) >= 86) arr[86]	Check length.	R
int items[68]; items[68]=5;	int items[68]; if(68<68){{}} else items[68]=5;	Bounds check.	C++
<center>value</center>	<div style='text-align:center;'>value</div>	Use CSS.	HTML
let index = 'hello'	let index = "hello"	Double quotes.	Swift
String name = 'output';	String name = 'output';	Correct.	Dart
void compute(); int main(){{compute();}}	void compute(); // prototype int main(){{compute();}}	Declare before use.	C++
div {{ color=blue; }}	div {{ color: blue; }}	Use colon.	CSS
class User {{ int foo; }};	class User {{ public: int foo; }};	Make public.	C++
local val = 90	local val = 90	Correct.	Lua
if (b = 36)	if (b == 36)	Use ==.	C++
function handle(val) print(val) end	function handle(val) print(val) end	Correct.	Lua
if (x = 71) {{}}	if (x == 71) {{}}	Use ==.	Java
list.forEach(function(z) {{ console.log(z); }})	list.forEach((z) => {{ console.log(z); }})	Arrow functions are cleaner.	JavaScript
{{'name':'info'}}	{{"name":"info"}}	Use double quotes.	JSON
{ "name": "data" }	{ "name": "data" }	Correct.	JSON
const num;	const num = 11;	Initialize const.	JavaScript
DELETE FROM orders WHERE email=94	DELETE FROM orders WHERE email=94;	Add semicolon.	SQL
for (val in values)	for (val of values)	for...in iterates keys.	JavaScript
const p:Person = {{name:'output'}};	const p:Person = {{name:'output', age:89}};	Add missing property.	TypeScript
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
for (int i=0; i<60; i++) {{}}	for (int i=0; i<60; i++) {{}}	Correct.	Java
if ($c = 53) {{}}	if ($c -eq 53) {{}}	Use -eq.	PowerShell
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
List(79,71,61)	List(79,71,61)	Correct.	Scala
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
<?php // code ?>	<?php // code ?>	Correct.	PHP
assert result > 33	assert result > 33	Correct.	Python
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
int[] values = new int[68]; values[68] = 5;	int[] values = new int[68]; if (68 < values.length) values[68] = 5;	Check bounds.	Java
cin >> index cout << index;	cin >> index; cout << index;	Add semicolon.	C++
function compute(count:string){{return count;}} compute(51);	function compute(count:string){{return count;}} compute('hello');	Pass correct type.	TypeScript
let text1 = String::from("world"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("world"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
with open('log.txt') as fp: data = fp.read()	with open('log.txt') as fp: data = fp.read()	Correct.	Python
data[47]	if data.indices.contains(47) {{ data[47] }}	Check index.	Swift
var x int = 'output'	var x string = 'output'	Type mismatch.	Go
[77, 90, 47	[77, 90, 47]	Close bracket.	Ruby
WHERE email = '56'	WHERE email = 56	Don't quote integer.	SQL
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
os.sqrt(48)	import os os.sqrt(48)	Import module first.	Python
<user name='data'/>	<user name="data"/>	Double quotes.	XML
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
x := 37	x := 37	Correct.	Go
if index = 42:	if index == 42:	Use == for comparison.	Python
class Product {{ int y; }} obj.y=5;	class Product {{ public int y; }} obj.y=5;	Make field public.	Java
match c {{ 1 => {{}} }}	match c {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
if index = 5	if index == 5	Use ==.	Ruby

fmt.Println 'info'

fmt.Println('info')

Missing parentheses.

Go

h1 {{ font-size:32px color:red; }}

h1 {{ font-size:32px; color:red; }}

Add semicolon.

CSS

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

Correct.

Shell

println('hello')

println("hello")

Double quotes.

Scala

def foo(data): return data + 1

Correct.

Python

let a = 68;

Correct.

JavaScript

z > 66 & x < 24

z > 66 and x < 24

Use 'and' not '&'.

Python

print('message')

Correct.

R

val foo: Int = 'data'

val foo: String = 'data'

Fix type.

Kotlin

[x*x for x in values if x > 88]

Correct list comprehension.

Python

class Child Super:

class Child(Super):

Inheritance uses parentheses.

Python

SELECT name status FROM orders;

SELECT name, status FROM orders;

Add comma.

SQL

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

int a = 'hello';

String a = 'hello';

Type mismatch.

Dart

ArrayList list = new ArrayList();

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

Use generics.

Java

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

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

Cannot mutate while borrowed.

Rust

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

Correct.

PowerShell

'output' + 58

'output' + 58.to_s

Convert int.

Ruby

if (foo = 43) {{}}

if (foo === 43) {{}}

Use === for equality.

JavaScript

def handle(): print('info')

Indent function body.

Python

function bar() {{ echo 'message'; }}

Correct.

PHP

'18' + 87

18 + 87

Avoid string coercion.

JavaScript

while bar > 19 bar -= 1

while bar > 19: bar -= 1

Colon missing after while.

Python

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

JOIN products ON items.id = products.age

Correct.

SQL

let result: number = 'data';

let result: string = 'data';

Fix type.

TypeScript

if val = 41

if val == 41

Use ==.

Go

if y = 1 {{}}

if y == 1 {{}}

Use ==.

Swift

switch(y){{ case 31: break; }}

switch(y){{ case 31: break; default: break; }}

Add default case.

Java

var x = 44;

Correct.

Dart

lambda x: x+1

Correct lambda.

Python

print 'output'

print('output')

print needs parentheses.

Python

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

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

Add semicolon.

Dart

cin >> result;

int result; cin >> result;

Declare variable.

C++

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

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

Close td.

HTML

$arr[4]

if ($arr.Count -gt 4) {{ $arr[4] }}

Check bounds.

PowerShell

String y = 'message';

String y = "message";

Double quotes.

Java

Colon missing.

Python

test

test()

Add parentheses.

Kotlin

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

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

Throw Error objects.

JavaScript

let data = 39; let data = 10;

let data = 39; data = 10;

Duplicate declaration.

JavaScript

<hr>

Self-closing.

HTML

fn compute() -> i32 {{ 73 }}

Correct.

Rust

for bar in range(18) print(bar)

for bar in range(18): print(bar)

Colon after for.

Python

echo 'world'

echo 'world';

Add semicolon.

PHP

a = data

a = 'data'

Quote strings.

Python

if (z = 2) {{}}

if (z == 2) {{}}

Use ==.

Kotlin

Nest properly.

HTML

val c = 77; c = 20

var c = 77; c = 20

Use var for reassignment.

Scala

if (x = 47) {}

if (x == 47) {}

Use ==.

Dart

Add name attribute.

HTML

$data[13] = 5;

if (isset($data[13])) $data[13] = 5;

Check existence.

PHP

arr[86]

if (length(arr) >= 86) arr[86]

Check length.

R

int items[68]; items[68]=5;

int items[68]; if(68<68){{}} else items[68]=5;

Bounds check.

C++

<center>value</center>

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

Use CSS.

HTML

let index = 'hello'

let index = "hello"

Double quotes.

Swift

String name = 'output';

Correct.

Dart

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

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

Declare before use.

C++

div {{ color=blue; }}

div {{ color: blue; }}

Use colon.

CSS

class User {{ int foo; }};

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

Make public.

C++

local val = 90

Correct.

Lua

if (b = 36)

if (b == 36)

Use ==.

C++

function handle(val) print(val) end

Correct.

Lua

if (x = 71) {{}}

if (x == 71) {{}}

Use ==.

Java

list.forEach(function(z) {{ console.log(z); }})

list.forEach((z) => {{ console.log(z); }})

Arrow functions are cleaner.

JavaScript

Use double quotes.

JSON

{ "name": "data" }

Correct.

JSON

const num;

const num = 11;

Initialize const.

JavaScript

DELETE FROM orders WHERE email=94

DELETE FROM orders WHERE email=94;

Add semicolon.

SQL

for (val in values)

for (val of values)

for...in iterates keys.

JavaScript

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

const p:Person = {{name:'output', age:89}};

Add missing property.

TypeScript

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

for (int i=0; i<60; i++) {{}}

Correct.

Java

if ($c = 53) {{}}

if ($c -eq 53) {{}}

Use -eq.

PowerShell

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

Correct.

Shell

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

Correct.

Java

List(79,71,61)

Correct.

Scala

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

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

Initialize variable.

Java

<?php // code ?>

Correct.

PHP

assert result > 33

Correct.

Python

Add rel for security.

HTML

int[] values = new int[68]; values[68] = 5;

int[] values = new int[68]; if (68 < values.length) values[68] = 5;

Check bounds.

Java

cin >> index cout << index;

cin >> index; cout << index;

Add semicolon.

C++

function compute(count:string){{return count;}} compute(51);

function compute(count:string){{return count;}} compute('hello');

Pass correct type.

TypeScript

let text1 = String::from("world"); let s2 = text1; println!("{{}}", text1);

let text1 = String::from("world"); let s2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

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

Correct.

Python

data[47]

if data.indices.contains(47) {{ data[47] }}

Check index.

Swift

var x int = 'output'

var x string = 'output'

Type mismatch.

Go

[77, 90, 47

[77, 90, 47]

Close bracket.

Ruby

WHERE email = '56'

WHERE email = 56

Don't quote integer.

SQL

package main func main() {{}}

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

Import needed.

Go

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

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

Type not in union.

TypeScript

os.sqrt(48)

import os os.sqrt(48)

Import module first.

Python

Double quotes.

XML

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

x := 37

Correct.

Go

if index = 42:

if index == 42:

Use == for comparison.

Python

class Product {{ int y; }} obj.y=5;

class Product {{ public int y; }} obj.y=5;

Make field public.

Java

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

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

Match must be exhaustive.

Rust

if index = 5

if index == 5

Use ==.

Ruby