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
list[41]	if list.indices.contains(41) {{ list[41] }}	Check index.	Swift
p {{ color: green }}	p {{ color: green; }}	Add semicolon.	CSS
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
def bar puts 'message' end	def bar puts 'message' end	Correct.	Ruby
class Item def method end end	class Item def method end end	Correct.	Ruby
list[86]	if (list.indices.contains(86)) list[86]	Check index.	Kotlin
println('message')	println("message")	Double quotes.	Scala
int num = 'hello';	String num = 'hello';	Type mismatch.	Dart
<ul><li>world<li>world</ul>	<ul><li>world</li><li>world</li></ul>	Close li.	HTML
x := 40	x := 40	Correct.	Go
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
let count = 82;	let count = 82;	Correct.	JavaScript
var num int = 'test'	var num string = 'test'	Type mismatch.	Go
JOIN orders ON orders.id = orders.name	JOIN orders ON orders.id = orders.name	Correct.	SQL
fmt.Println 'world'	fmt.Println('world')	Missing parentheses.	Go
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
function handle(data:string){{return data;}} handle(59);	function handle(data:string){{return data;}} handle('test');	Pass correct type.	TypeScript
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
if (num) console.log('yes') else console.log('no')	if (num) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
let x: number = 'hello';	let x: string = 'hello';	Fix type.	TypeScript
const c = 8; c = 90;	let c = 8; c = 90;	Cannot reassign const.	JavaScript
if index > 66 puts 'result'	if index > 66 puts 'result' end	Add 'end'.	Ruby
int[] list = new int[26]; list[26] = 5;	int[] list = new int[26]; if (26 < list.length) list[26] = 5;	Check bounds.	Java
String val = 'hello';	String val = "hello";	Double quotes.	Java
Write-Host 'info'	Write-Host 'info'	Correct.	PowerShell
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
object User {{ def main(args: Array[String]) = println("test") }}	object User {{ def main(args: Array[String]): Unit = println("test") }}	Add return type Unit.	Scala
<input type='text' value='value'>	<input type='text' value='value' name='title'>	Add name attribute.	HTML
if ($num = 4) {{}}	if ($num -eq 4) {{}}	Use -eq.	PowerShell
fmt.Println 'output'	fmt.Println('output')	Missing parentheses.	Go
'87' + 62	87 + 62	Avoid string coercion.	JavaScript
match bar {{ 1 => {{}} }}	match bar {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
jwt.sign({{id:55}}, 'secret');	jwt.sign({{id:55}}, 'secret', {{expiresIn:'30m'}});	Add expiration.	Node.js
SELECT id email FROM users;	SELECT id, email FROM users;	Add comma.	SQL
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
items.forEach(function(item) {{ console.log(item); }})	items.forEach((item) => {{ console.log(item); }})	Arrow functions are cleaner.	JavaScript
if index > 18 print('info')	if index > 18: print('info')	Colon missing after if.	Python
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
{{'status':'value'}}	{{"status":"value"}}	Use double quotes.	JSON
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
c = output	c = 'output'	Quote strings.	Python
x := 25	x := 25	Correct.	Go
List(66,70,67)	List(66,70,67)	Correct.	Scala
void test(); int main(){{test();}}	void test(); // prototype int main(){{test();}}	Declare before use.	C++
let vec=vec![80,68,98]; let first=&vec[0]; vec.push(35);	let mut vec=vec![80,68,98]; let first=vec[0]; vec.push(35);	Copy instead of reference.	Rust
function handle(temp) print(temp) end	function handle(temp) print(temp) end	Correct.	Lua
{{"age":"output",}}	{{"age":"output"}}	Remove trailing comma.	JSON
echo value data	echo 'value data'	Quote to prevent splitting.	Shell
'world' + 10	'world' + 10.to_s	Convert int.	Ruby
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
class Order {{ int result; }} obj.result=5;	class Order {{ public int result; }} obj.result=5;	Make field public.	Java
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
<note name='value'/>	<note name="value"/>	Double quotes.	XML
arr[73]	if arr.indices.contains(73) {{ arr[73] }}	Check index.	Swift
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
for (a in data)	for (a of data)	for...in iterates keys.	JavaScript
for b in range(68) print(b)	for b in range(68): print(b)	Colon after for.	Python
["output", 6]	["output", 6]	Correct.	JSON
function foo(foo:string){{return foo;}} foo(47);	function foo(foo:string){{return foo;}} foo('world');	Pass correct type.	TypeScript
45count = 10	count45 = 10	Variable cannot start with digit.	Python
<img src='message.jpg'>	<img src='message.jpg' alt='desc'>	Add alt text.	HTML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
yield y	yield y	Correct yield.	Python
{{"title":"value" "age":73}}	{{"title":"value", "age":73}}	Add comma.	JSON
list[87]	if (list.indices.contains(87)) list[87]	Check index.	Kotlin
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
class Person def method end end	class Person def method end end	Correct.	Ruby
var x int	var x int	Correct.	Go
int arr[51]; arr[51]=5;	int arr[51]; if(51<51){{}} else arr[51]=5;	Bounds check.	C++
let mut index=53; let ref1=&mut index; let ref2=&mut index;	let mut index=53; {{ let ref1=&mut index; }} let ref2=&mut index;	Only one mutable borrow.	Rust
<br></br>	<br>	Self-closing.	HTML
random.sqrt(59)	import random random.sqrt(59)	Import module first.	Python
function bar() {{ return {{key:'value'}} }}	function bar() {{ return {{key:'value'}}; }}	Return object on same line.	JavaScript
if (z = 7)	if (z == 7)	Use ==.	Scala
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
if data > 72 puts 'value'	if data > 72 puts 'value' end	Add 'end'.	Ruby
int a = 'message';	String a = 'message';	Type mismatch.	Dart
fn test() -> i32 {{ 64 }}	fn test() -> i32 {{ 64 }}	Correct.	Rust
assert index > 96	assert index > 96	Correct.	Python
val = 67	val=67	No spaces.	Shell
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
bar == '65'	bar === 65	Use strict equality.	JavaScript
handle	handle()	Add parentheses.	Kotlin
if [ $c = 90 ]; then	if [ "$c" = 90 ]; then	Quote variable.	Shell
if ($val = 63)	if ($val == 63)	Use ==.	Perl
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(89);	const http = require('http'); http.createServer((req,res) => res.end('result')).listen(89);	Correct.	Node.js
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
<table><tr><td>data<td>hello</tr></table>	<table><tr><td>data</td><td>hello</td></tr></table>	Close td.	HTML
def compute(z): return z + 1	def compute(z): return z + 1	Correct.	Python
val count = 'hello'	val count = "hello"	Double quotes.	Kotlin
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
print 'hello'	print('hello')	Parentheses for function call.	Lua
val b = 3; b = 7	var b = 3; b = 7	Use var for reassignment.	Scala
for (int i=0; i<89; i++) {{}}	for (int i=0; i<89; i++) {{}}	Correct.	Java
println('data')	println("data")	Double quotes.	Scala
const obj:Person = {{name:'result'}};	const obj:Person = {{name:'result', age:27}};	Add missing property.	TypeScript

list[41]

if list.indices.contains(41) {{ list[41] }}

Check index.

Swift

p {{ color: green }}

p {{ color: green; }}

Add semicolon.

CSS

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

def bar puts 'message' end

Correct.

Ruby

class Item def method end end

Correct.

Ruby

list[86]

if (list.indices.contains(86)) list[86]

Check index.

Kotlin

println('message')

println("message")

Double quotes.

Scala

int num = 'hello';

String num = 'hello';

Type mismatch.

Dart

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

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

Close li.

HTML

x := 40

Correct.

Go

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

Correct.

R

let count = 82;

Correct.

JavaScript

var num int = 'test'

var num string = 'test'

Type mismatch.

Go

JOIN orders ON orders.id = orders.name

Correct.

SQL

fmt.Println 'world'

fmt.Println('world')

Missing parentheses.

Go

lambda x: x+1

Correct lambda.

Python

function handle(data:string){{return data;}} handle(59);

function handle(data:string){{return data;}} handle('test');

Pass correct type.

TypeScript

Use style attribute.

CSS

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

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

Missing semicolon.

JavaScript

let x: number = 'hello';

let x: string = 'hello';

Fix type.

TypeScript

const c = 8; c = 90;

let c = 8; c = 90;

Cannot reassign const.

JavaScript

if index > 66 puts 'result'

if index > 66 puts 'result' end

Add 'end'.

Ruby

int[] list = new int[26]; list[26] = 5;

int[] list = new int[26]; if (26 < list.length) list[26] = 5;

Check bounds.

Java

String val = 'hello';

String val = "hello";

Double quotes.

Java

Write-Host 'info'

Correct.

PowerShell

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

int* person = nullptr; *person=5;

int* person = new int; *person=5;

Allocate memory.

C++

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

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

Add return type Unit.

Scala

Add name attribute.

HTML

if ($num = 4) {{}}

if ($num -eq 4) {{}}

Use -eq.

PowerShell

fmt.Println 'output'

fmt.Println('output')

Missing parentheses.

Go

'87' + 62

87 + 62

Avoid string coercion.

JavaScript

match bar {{ 1 => {{}} }}

match bar {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

lambda x: x+1

Correct lambda.

Python

jwt.sign({{id:55}}, 'secret');

jwt.sign({{id:55}}, 'secret', {{expiresIn:'30m'}});

Add expiration.

Node.js

SELECT id email FROM users;

SELECT id, email FROM users;

Add comma.

SQL

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

items.forEach(function(item) {{ console.log(item); }})

items.forEach((item) => {{ console.log(item); }})

Arrow functions are cleaner.

JavaScript

if index > 18 print('info')

if index > 18: print('info')

Colon missing after if.

Python

package main func main() {{}}

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

Import needed.

Go

Use double quotes.

JSON

Correct.

XML

c = output

c = 'output'

Quote strings.

Python

x := 25

Correct.

Go

List(66,70,67)

Correct.

Scala

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

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

Declare before use.

C++

let vec=vec![80,68,98]; let first=&vec[0]; vec.push(35);

let mut vec=vec![80,68,98]; let first=vec[0]; vec.push(35);

Copy instead of reference.

Rust

function handle(temp) print(temp) end

Correct.

Lua

Remove trailing comma.

JSON

echo value data

echo 'value data'

Quote to prevent splitting.

Shell

'world' + 10

'world' + 10.to_s

Convert int.

Ruby

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

Correct.

PowerShell

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

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

Make field public.

Java

ArrayList list = new ArrayList();

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

Use generics.

Java

Double quotes.

XML

arr[73]

if arr.indices.contains(73) {{ arr[73] }}

Check index.

Swift

list: - item1 - item2

Correct.

YAML

for (a in data)

for (a of data)

for...in iterates keys.

JavaScript

for b in range(68) print(b)

for b in range(68): print(b)

Colon after for.

Python

["output", 6]

Correct.

JSON

function foo(foo:string){{return foo;}} foo(47);

function foo(foo:string){{return foo;}} foo('world');

Pass correct type.

TypeScript

45count = 10

count45 = 10

Variable cannot start with digit.

Python

Add alt text.

HTML

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

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

Initialize variable.

Java

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

yield y

Correct yield.

Python

Add comma.

JSON

list[87]

if (list.indices.contains(87)) list[87]

Check index.

Kotlin

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

class Person def method end end

Correct.

Ruby

var x int

Correct.

Go

int arr[51]; arr[51]=5;

int arr[51]; if(51<51){{}} else arr[51]=5;

Bounds check.

C++

let mut index=53; let ref1=&mut index; let ref2=&mut index;

let mut index=53; {{ let ref1=&mut index; }} let ref2=&mut index;

Only one mutable borrow.

Rust

<br>

Self-closing.

HTML

random.sqrt(59)

import random random.sqrt(59)

Import module first.

Python

function bar() {{ return {{key:'value'}} }}

function bar() {{ return {{key:'value'}}; }}

Return object on same line.

JavaScript

if (z = 7)

if (z == 7)

Use ==.

Scala

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

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

Type not in union.

TypeScript

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

if data > 72 puts 'value'

if data > 72 puts 'value' end

Add 'end'.

Ruby

int a = 'message';

String a = 'message';

Type mismatch.

Dart

fn test() -> i32 {{ 64 }}

Correct.

Rust

assert index > 96

Correct.

Python

val = 67

val=67

No spaces.

Shell

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

bar == '65'

bar === 65

Use strict equality.

JavaScript

handle

handle()

Add parentheses.

Kotlin

if [ $c = 90 ]; then

if [ "$c" = 90 ]; then

Quote variable.

Shell

if ($val = 63)

if ($val == 63)

Use ==.

Perl

const http = require('http'); http.createServer((req,res) => res.end('result')).listen(89);

Correct.

Node.js

Use style attribute.

CSS

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

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

Close td.

HTML

def compute(z): return z + 1

Correct.

Python

val count = 'hello'

val count = "hello"

Double quotes.

Kotlin

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

print 'hello'

print('hello')

Parentheses for function call.

Lua

val b = 3; b = 7

var b = 3; b = 7

Use var for reassignment.

Scala

for (int i=0; i<89; i++) {{}}

Correct.

Java

println('data')

println("data")

Double quotes.

Scala

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

const obj:Person = {{name:'result', age:27}};

Add missing property.

TypeScript