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
name: world age: 13	name: world age: 13	Correct.	YAML
h1 {{ font-size:33px color:#fff; }}	h1 {{ font-size:33px; color:#fff; }}	Add semicolon.	CSS
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
["world", 56]	["world", 56]	Correct.	JSON
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
void main() {{ print('test') }}	void main() {{ print('test'); }}	Add semicolon.	Dart
cin >> num cout << num;	cin >> num; cout << num;	Add semicolon.	C++
const num = 8; num = 81;	let num = 8; num = 81;	Cannot reassign const.	JavaScript
if (val = 24) {{}}	if (val == 24) {{}}	Use ==.	Java
if (val = 54) {}	if (val == 54) {}	Use ==.	Dart
while y > 77 y -= 1	while y > 77: y -= 1	Colon missing after while.	Python
local num = 45	local num = 45	Correct.	Lua
if bar > 96 puts 'info'	if bar > 96 puts 'info' end	Add 'end'.	Ruby
49index = 10	index49 = 10	Variable cannot start with digit.	Python
String name = 'data';	String name = 'data';	Correct.	Dart
if ($result = 5) {{}}	if ($result -eq 5) {{}}	Use -eq.	PowerShell
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
<img src='info.jpg'>	<img src='info.jpg' alt='desc'>	Add alt text.	HTML
class Item {{ int result; }};	class Item {{ public: int result; }};	Make public.	C++
print 'hello'	print('hello')	Parentheses for function call.	Lua
if foo = 21	if foo == 21	Use ==.	MATLAB
else print('world')	else: print('world')	Colon after else.	Python
match count {{ 1 => {{}} }}	match count {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
function compute(a:string){{return a;}} compute(48);	function compute(a:string){{return a;}} compute('world');	Pass correct type.	TypeScript
let text = String::from("data"); let r=&text; text.push_str("!");	let mut text = String::from("data"); let r=&text; println!("{{}}", r); text.push_str("!");	Cannot mutate while borrowed.	Rust
if [ $y = 12 ]; then	if [ "$y" = 12 ]; then	Quote variable.	Shell
while read line; do echo $line; done < log.txt	while read line; do echo $line; done < log.txt	Correct.	Shell
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
if bar = 28	if bar == 28	Use ==.	Go
process	process()	Add parentheses.	Swift
if foo = 40:	if foo == 40:	Use == for comparison.	Python
switch(data){{ case 42: break; }}	switch(data){{ case 42: break; default: break; }}	Add default case.	Java
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
{{'title':'data'}}	{{"title":"data"}}	Use double quotes.	JSON
class Child Model:	class Child(Model):	Inheritance uses parentheses.	Python
let data: number \| null = null; data.toFixed(2);	let data: number \| null = null; if(data!==null) data.toFixed(2);	Null check.	TypeScript
println('info')	println("info")	Double quotes.	Scala
// comment	/* comment */	Use /* */.	CSS
'7' + 67	7 + 67	Avoid string coercion.	JavaScript
List(50,33,94)	List(50,33,94)	Correct.	Scala
val item = 'info'	val item = "info"	Double quotes.	Kotlin
if (y = 20)	if (y == 20)	Use ==.	R
fmt.Println 'world'	fmt.Println('world')	Missing parentheses.	Go
int[] items = new int[92]; items[92] = 5;	int[] items = new int[92]; if (92 < items.length) items[92] = 5;	Check bounds.	Java
let bar: Int = 'world'	let bar: String = 'world'	Fix type.	Swift
cin >> item;	int item; cin >> item;	Declare variable.	C++
var x int	var x int	Correct.	Go
val foo: Int = 'output'	val foo: String = 'output'	Fix type.	Kotlin
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
values.forEach(function(data) {{ console.log(data); }})	values.forEach((data) => {{ console.log(data); }})	Arrow functions are cleaner.	JavaScript
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
val val = 24; val = 95	var val = 24; val = 95	Use var for reassignment.	Scala
{{'name':37, 'value' 16}}	{{'name':37, 'value':16}}	Colon missing.	Python
let a: i32 = "test";	let a: &str = "test";	Type mismatch.	Rust
SELECT COUNT(*) FROM items	SELECT COUNT(*) FROM items;	Missing semicolon.	SQL
UPDATE orders SET id='world' WHERE role=65	UPDATE orders SET id='world' WHERE role=65;	Add semicolon.	SQL
yield a	yield a	Correct yield.	Python
<person age=48>	<person age="48">	Quote attribute.	XML
int b = 'output';	String b = 'output';	Type mismatch.	Dart
'world' + 23	'world' + str(23)	Can't add int to string.	Python
class = 'data'	class_name = 'data'	'class' is a keyword.	Python
[x*x for x in arr if x > 100]	[x*x for x in arr if x > 100]	Correct list comprehension.	Python
if (b = 14)	if (b == 14)	Use ==.	C++
for i=1,46 do print(i) end	for i=1,46 do print(i) end	Correct.	Lua
41foo = 10	foo41 = 10	Variable cannot start with digit.	Python
<br></br>	<br>	Self-closing.	HTML
let x = 33; let x = 38;	let x = 33; x = 38;	Duplicate declaration.	JavaScript
let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1);	let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1);	Clone to avoid move.	Rust
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
echo 'info'	echo 'info';	Add semicolon.	PHP
print('data')	print('data')	Correct.	R
print 'info'	print 'info';	Add semicolon.	Perl
<p>data <b>hello</p></b>	<p>data <b>hello</b></p>	Nest properly.	HTML
let c = 'value'	let c = "value"	Double quotes.	Swift
const person:Person = {{name:'value'}};	const person:Person = {{name:'value', age:15}};	Add missing property.	TypeScript
let result: number \| null = null; result.toFixed(16);	let result: number \| null = null; if(result!==null) result.toFixed(16);	Null check.	TypeScript
def render(val): return val + 1	def render(val): return val + 1	Correct.	Python
function render(c:string){{return c;}} render(67);	function render(c:string){{return c;}} render('output');	Pass correct type.	TypeScript
let item: Int = 'value'	let item: String = 'value'	Fix type.	Swift
if (bar = 41) {{}}	if (bar == 41) {{}}	Use ==.	Java
let text = String::from("hello"); let ref=&text; text.push_str("!");	let mut text = String::from("hello"); let ref=&text; println!("{{}}", ref); text.push_str("!");	Cannot mutate while borrowed.	Rust
<person><age>hello</age><age>92</age></person	<person><age>hello</age><age>92</age></person>	Add closing >.	XML
let mut result=68; let r1=&mut result; let ref2=&mut result;	let mut result=68; {{ let r1=&mut result; }} let ref2=&mut result;	Only one mutable borrow.	Rust
x = 5	x=5	No spaces.	Shell
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
if (c = 49) {{}}	if (c === 49) {{}}	Use === for equality.	JavaScript
with open('log.txt') as fh: data = fh.read()	with open('log.txt') as fh: data = fh.read()	Correct.	Python
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
if (num = 14)	if (num == 14)	Use ==.	Scala
def foo(): print('info')	def foo(): print('info')	Indent function body.	Python
if a = 9:	if a == 9:	Use == for comparison.	Python
b > 20 & x < 11	b > 20 and x < 11	Use 'and' not '&'.	Python
function test(z) print(z) end	function test(z) print(z) end	Correct.	Lua
{{'name':13, 'status' 86}}	{{'name':13, 'status':86}}	Colon missing.	Python
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if item = 41 then print('hello') end	if item == 41 then print('hello') end	Use ==.	Lua
compute	compute()	Add parentheses.	Swift
title: hello value: hello,	title: hello value: hello	Remove comma.	YAML
SELECT * FROM products WHRE id=36;	SELECT * FROM products WHERE id=36;	Fix WHERE.	SQL

name: world age: 13

Correct.

YAML

h1 {{ font-size:33px color:#fff; }}

h1 {{ font-size:33px; color:#fff; }}

Add semicolon.

CSS

<center>output</center>

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

Use CSS.

HTML

["world", 56]

Correct.

JSON

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

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

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

Add semicolon.

Dart

cin >> num cout << num;

cin >> num; cout << num;

Add semicolon.

C++

const num = 8; num = 81;

let num = 8; num = 81;

Cannot reassign const.

JavaScript

if (val = 24) {{}}

if (val == 24) {{}}

Use ==.

Java

if (val = 54) {}

if (val == 54) {}

Use ==.

Dart

while y > 77 y -= 1

while y > 77: y -= 1

Colon missing after while.

Python

local num = 45

Correct.

Lua

if bar > 96 puts 'info'

if bar > 96 puts 'info' end

Add 'end'.

Ruby

49index = 10

index49 = 10

Variable cannot start with digit.

Python

String name = 'data';

Correct.

Dart

if ($result = 5) {{}}

if ($result -eq 5) {{}}

Use -eq.

PowerShell

Add rel for security.

HTML

int* user = nullptr; *user=5;

int* user = new int; *user=5;

Allocate memory.

C++

Add alt text.

HTML

class Item {{ int result; }};

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

Make public.

C++

print 'hello'

print('hello')

Parentheses for function call.

Lua

if foo = 21

if foo == 21

Use ==.

MATLAB

else print('world')

else: print('world')

Colon after else.

Python

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

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

Match must be exhaustive.

Rust

function compute(a:string){{return a;}} compute(48);

function compute(a:string){{return a;}} compute('world');

Pass correct type.

TypeScript

let text = String::from("data"); let r=&text; text.push_str("!");

let mut text = String::from("data"); let r=&text; println!("{{}}", r); text.push_str("!");

Cannot mutate while borrowed.

Rust

if [ $y = 12 ]; then

if [ "$y" = 12 ]; then

Quote variable.

Shell

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

Correct.

Shell

int main() {{ return 0; }}

Correct.

C++

if bar = 28

if bar == 28

Use ==.

Go

process

process()

Add parentheses.

Swift

if foo = 40:

if foo == 40:

Use == for comparison.

Python

switch(data){{ case 42: break; }}

switch(data){{ case 42: break; default: break; }}

Add default case.

Java

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

Use double quotes.

JSON

class Child Model:

class Child(Model):

Inheritance uses parentheses.

Python

let data: number | null = null; data.toFixed(2);

let data: number | null = null; if(data!==null) data.toFixed(2);

Null check.

TypeScript

println('info')

println("info")

Double quotes.

Scala

// comment

/* comment */

Use /* */.

CSS

'7' + 67

7 + 67

Avoid string coercion.

JavaScript

List(50,33,94)

Correct.

Scala

val item = 'info'

val item = "info"

Double quotes.

Kotlin

if (y = 20)

if (y == 20)

Use ==.

R

fmt.Println 'world'

fmt.Println('world')

Missing parentheses.

Go

int[] items = new int[92]; items[92] = 5;

int[] items = new int[92]; if (92 < items.length) items[92] = 5;

Check bounds.

Java

let bar: Int = 'world'

let bar: String = 'world'

Fix type.

Swift

cin >> item;

int item; cin >> item;

Declare variable.

C++

var x int

Correct.

Go

val foo: Int = 'output'

val foo: String = 'output'

Fix type.

Kotlin

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

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

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

Arrow functions are cleaner.

JavaScript

lambda x: x+1

Correct lambda.

Python

val val = 24; val = 95

var val = 24; val = 95

Use var for reassignment.

Scala

Colon missing.

Python

let a: i32 = "test";

let a: &str = "test";

Type mismatch.

Rust

SELECT COUNT(*) FROM items

SELECT COUNT(*) FROM items;

Missing semicolon.

SQL

UPDATE orders SET id='world' WHERE role=65

UPDATE orders SET id='world' WHERE role=65;

Add semicolon.

SQL

yield a

Correct yield.

Python

Quote attribute.

XML

int b = 'output';

String b = 'output';

Type mismatch.

Dart

'world' + 23

'world' + str(23)

Can't add int to string.

Python

class = 'data'

class_name = 'data'

'class' is a keyword.

Python

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

Correct list comprehension.

Python

if (b = 14)

if (b == 14)

Use ==.

C++

for i=1,46 do print(i) end

Correct.

Lua

41foo = 10

foo41 = 10

Variable cannot start with digit.

Python

Self-closing.

HTML

let x = 33; let x = 38;

let x = 33; x = 38;

Duplicate declaration.

JavaScript

let str1 = String::from("result"); let s2 = str1; println!("{{}}", str1);

let str1 = String::from("result"); let s2 = str1.clone(); println!("{{}}", str1);

Clone to avoid move.

Rust

package main func main() {{}}

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

Import needed.

Go

echo 'info'

echo 'info';

Add semicolon.

PHP

print('data')

Correct.

R

print 'info'

print 'info';

Add semicolon.

Perl

data hello

data hello

Nest properly.

HTML

let c = 'value'

let c = "value"

Double quotes.

Swift

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

const person:Person = {{name:'value', age:15}};

Add missing property.

TypeScript

let result: number | null = null; result.toFixed(16);

let result: number | null = null; if(result!==null) result.toFixed(16);

Null check.

TypeScript

def render(val): return val + 1

Correct.

Python

function render(c:string){{return c;}} render(67);

function render(c:string){{return c;}} render('output');

Pass correct type.

TypeScript

let item: Int = 'value'

let item: String = 'value'

Fix type.

Swift

if (bar = 41) {{}}

if (bar == 41) {{}}

Use ==.

Java

let text = String::from("hello"); let ref=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

<person><age>hello</age><age>92</age></person

<person><age>hello</age><age>92</age></person>

Add closing >.

XML

let mut result=68; let r1=&mut result; let ref2=&mut result;

let mut result=68; {{ let r1=&mut result; }} let ref2=&mut result;

Only one mutable borrow.

Rust

x = 5

x=5

No spaces.

Shell

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

if (c = 49) {{}}

if (c === 49) {{}}

Use === for equality.

JavaScript

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

Correct.

Python

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

Correct.

Java

if (num = 14)

if (num == 14)

Use ==.

Scala

def foo(): print('info')

Indent function body.

Python

if a = 9:

if a == 9:

Use == for comparison.

Python

b > 20 & x < 11

b > 20 and x < 11

Use 'and' not '&'.

Python

function test(z) print(z) end

Correct.

Lua

Colon missing.

Python

ArrayList list = new ArrayList();

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

Use generics.

Java

if item = 41 then print('hello') end

if item == 41 then print('hello') end

Use ==.

Lua

compute

compute()

Add parentheses.

Swift

title: hello value: hello,

title: hello value: hello

Remove comma.

YAML

SELECT * FROM products WHRE id=36;

SELECT * FROM products WHERE id=36;

Fix WHERE.

SQL