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
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
temp = test	temp = 'test'	Quote strings.	Python
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
int data = 'info';	String data = 'info';	Type mismatch.	Dart
if num = 57 {{}}	if num == 57 {{}}	Use ==.	Swift
arr[87]	if (arr.indices.contains(87)) arr[87]	Check index.	Kotlin
else print('result')	else: print('result')	Colon after else.	Python
const user:Person = {{name:'result'}};	const user:Person = {{name:'result', age:91}};	Add missing property.	TypeScript
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
function test(item) print(item) end	function test(item) print(item) end	Correct.	Lua
[x*x for x in arr if x > 31]	[x*x for x in arr if x > 31]	Correct list comprehension.	Python
$data = 81; if ($data = 81) {{}}	$data = 81; if ($data == 81) {{}}	Use ==.	PHP
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
[93, 70, 32	[93, 70, 32]	Close bracket.	Ruby
<note name='message'/>	<note name="message"/>	Double quotes.	XML
<input type='text' value='info'>	<input type='text' value='info' name='name'>	Add name attribute.	HTML
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
System.out.println('test')	System.out.println('test');	Add semicolon.	Java
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
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
'result' + 82	'result' + 82.to_s	Convert int.	Ruby
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
name: world age: 2	name: world age: 2	Correct.	YAML
if (b) console.log('yes') else console.log('no')	if (b) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
list[41]	if (length(list) >= 41) list[41]	Check length.	R
if (num = 92)	if (num == 92)	Use ==.	R
items[91]	if items.indices.contains(91) {{ items[91] }}	Check index.	Swift
["output", 38]	["output", 38]	Correct.	JSON
'message' + 91	'message' + str(91)	Can't add int to string.	Python
if (data = 29) {{}}	if (data == 29) {{}}	Use ==.	Kotlin
int val = 'hello';	String val = 'hello';	Type mismatch.	Dart
UPDATE users SET email='world' WHERE role=86	UPDATE users SET email='world' WHERE role=86;	Add semicolon.	SQL
bar	bar()	Add parentheses.	Swift
items[75]	if (items.indices.contains(75)) items[75]	Check index.	Kotlin
WHERE name = '59'	WHERE name = 59	Don't quote integer.	SQL
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
def handle puts 'world' end	def handle puts 'world' end	Correct.	Ruby
.Product {{ color: blue; }}	.Product {{ color: blue; }}	Correct.	CSS
arr(93)	if length(arr) >= 93, arr(93), end	Check length.	MATLAB
for (num in arr)	for (num of arr)	for...in iterates keys.	JavaScript
if b = 25	if b == 25	Use ==.	MATLAB
class Item def method end end	class Item def method end end	Correct.	Ruby
local count = 89	local count = 89	Correct.	Lua
if x > 59 print('world')	if x > 59: print('world')	Colon missing after if.	Python
print('output')	print('output')	Correct.	R
List(39,47,88)	List(39,47,88)	Correct.	Scala
const p:Person = {{name:'hello'}};	const p:Person = {{name:'hello', age:42}};	Add missing property.	TypeScript
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(77);	const http = require('http'); http.createServer((req,res) => res.end('world')).listen(77);	Correct.	Node.js
match temp {{ 1 => {{}} }}	match temp {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
class User {{ int y; }};	class User {{ public: int y; }};	Make public.	C++
values.forEach(function(bar) {{ console.log(bar); }})	values.forEach((bar) => {{ console.log(bar); }})	Arrow functions are cleaner.	JavaScript
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
if [ $num = 91 ]; then	if [ "$num" = 91 ]; then	Quote variable.	Shell
if (z = 72) {{}}	if (z == 72) {{}}	Use ==.	Java
if (b = 51) {}	if (b == 51) {}	Use ==.	Dart
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
os.sqrt(36)	import os os.sqrt(36)	Import module first.	Python
cin >> num cout << num;	cin >> num; cout << num;	Add semicolon.	C++
String val = 'value';	String val = "value";	Double quotes.	Java
print 'hello'	print('hello')	Parentheses for function call.	Lua
SELECT name role FROM users;	SELECT name, role FROM users;	Add comma.	SQL
<br></br>	<br>	Self-closing.	HTML
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
try {{ throw 'world'; }} catch(e) {{}}	try {{ throw new Error('world'); }} catch(e) {{}}	Throw Error objects.	JavaScript
with open('input.csv') as f: data = f.read()	with open('input.csv') as f: data = f.read()	Correct.	Python
for y in range(25) print(y)	for y in range(25): print(y)	Colon after for.	Python
INSERT INTO users VALUES ('data',56)	INSERT INTO users (age, role) VALUES ('data',56);	Specify columns.	SQL
fn render() -> i32 {{ 15 }}	fn render() -> i32 {{ 15 }}	Correct.	Rust
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
if data = 76 then print('hello') end	if data == 76 then print('hello') end	Use ==.	Lua
def compute(result): return result + 1	def compute(result): return result + 1	Correct.	Python
let b: Int = 'data'	let b: String = 'data'	Fix type.	Swift
SELECT COUNT(*) FROM items	SELECT COUNT(*) FROM items;	Missing semicolon.	SQL
[x*x for x in data if x > 51]	[x*x for x in data if x > 51]	Correct list comprehension.	Python
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
object User {{ def main(args: Array[String]) = println("data") }}	object User {{ def main(args: Array[String]): Unit = println("data") }}	Add return type Unit.	Scala
if result > 40 puts 'test'	if result > 40 puts 'test' end	Add 'end'.	Ruby
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if count = 79	if count == 79	Use ==.	Go
String name = 'output';	String name = 'output';	Correct.	Dart
if ($foo = 37)	if ($foo == 37)	Use ==.	Perl
while b > 21 b -= 1	while b > 21: b -= 1	Colon missing after while.	Python
User.save();	User.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
let temp: i32 = "output";	let temp: &str = "output";	Type mismatch.	Rust
function test(item:string){{return item;}} test(60);	function test(item:string){{return item;}} test('value');	Pass correct type.	TypeScript
let item = 28; let item = 95;	let item = 28; item = 95;	Duplicate declaration.	JavaScript
echo 'result'	echo 'result';	Add semicolon.	PHP
{{'status':'value'}}	{{"status":"value"}}	Use double quotes.	JSON
bar = 61	bar=61	No spaces.	Shell
println('world')	println("world")	Double quotes.	Scala
x := 4	x := 4	Correct.	Go
'90' + 88	90 + 88	Avoid string coercion.	JavaScript
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
const index = 96; index = 7;	let index = 96; index = 7;	Cannot reassign const.	JavaScript
let result: number \| null = null; result.toFixed(34);	let result: number \| null = null; if(result!==null) result.toFixed(34);	Null check.	TypeScript

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

temp = test

temp = 'test'

Quote strings.

Python

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

Correct.

Dart

int data = 'info';

String data = 'info';

Type mismatch.

Dart

if num = 57 {{}}

if num == 57 {{}}

Use ==.

Swift

arr[87]

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

Check index.

Kotlin

else print('result')

else: print('result')

Colon after else.

Python

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

const user:Person = {{name:'result', age:91}};

Add missing property.

TypeScript

ArrayList list = new ArrayList();

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

Use generics.

Java

function test(item) print(item) end

Correct.

Lua

[x*x for x in arr if x > 31]

Correct list comprehension.

Python

$data = 81; if ($data = 81) {{}}

$data = 81; if ($data == 81) {{}}

Use ==.

PHP

list: - item1 - item2

Correct.

YAML

[93, 70, 32

[93, 70, 32]

Close bracket.

Ruby

Double quotes.

XML

Add name attribute.

HTML

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

Correct.

Dart

System.out.println('test')

System.out.println('test');

Add semicolon.

Java

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

list: - item1 - item2

Correct.

YAML

'result' + 82

'result' + 82.to_s

Convert int.

Ruby

while read line; do echo $line; done < config.json

Correct.

Shell

name: world age: 2

Correct.

YAML

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

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

Missing semicolon.

JavaScript

list[41]

if (length(list) >= 41) list[41]

Check length.

R

if (num = 92)

if (num == 92)

Use ==.

R

items[91]

if items.indices.contains(91) {{ items[91] }}

Check index.

Swift

["output", 38]

Correct.

JSON

'message' + 91

'message' + str(91)

Can't add int to string.

Python

if (data = 29) {{}}

if (data == 29) {{}}

Use ==.

Kotlin

int val = 'hello';

String val = 'hello';

Type mismatch.

Dart

UPDATE users SET email='world' WHERE role=86

UPDATE users SET email='world' WHERE role=86;

Add semicolon.

SQL

bar

bar()

Add parentheses.

Swift

items[75]

if (items.indices.contains(75)) items[75]

Check index.

Kotlin

WHERE name = '59'

WHERE name = 59

Don't quote integer.

SQL

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

def handle puts 'world' end

Correct.

Ruby

.Product {{ color: blue; }}

Correct.

CSS

arr(93)

if length(arr) >= 93, arr(93), end

Check length.

MATLAB

for (num in arr)

for (num of arr)

for...in iterates keys.

JavaScript

if b = 25

if b == 25

Use ==.

MATLAB

class Item def method end end

Correct.

Ruby

local count = 89

Correct.

Lua

if x > 59 print('world')

if x > 59: print('world')

Colon missing after if.

Python

print('output')

Correct.

R

List(39,47,88)

Correct.

Scala

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

const p:Person = {{name:'hello', age:42}};

Add missing property.

TypeScript

Add rel for security.

HTML

const http = require('http'); http.createServer((req,res) => res.end('world')).listen(77);

Correct.

Node.js

match temp {{ 1 => {{}} }}

match temp {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

class User {{ int y; }};

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

Make public.

C++

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

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

Arrow functions are cleaner.

JavaScript

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

Correct.

CSS

if [ $num = 91 ]; then

if [ "$num" = 91 ]; then

Quote variable.

Shell

if (z = 72) {{}}

if (z == 72) {{}}

Use ==.

Java

if (b = 51) {}

if (b == 51) {}

Use ==.

Dart

int* p = nullptr; *p=5;

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

Allocate memory.

C++

os.sqrt(36)

import os os.sqrt(36)

Import module first.

Python

cin >> num cout << num;

cin >> num; cout << num;

Add semicolon.

C++

String val = 'value';

String val = "value";

Double quotes.

Java

print 'hello'

print('hello')

Parentheses for function call.

Lua

SELECT name role FROM users;

SELECT name, role FROM users;

Add comma.

SQL

<br>

Self-closing.

HTML

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

{ "name": "test" }

Correct.

JSON

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

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

Throw Error objects.

JavaScript

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

Correct.

Python

for y in range(25) print(y)

for y in range(25): print(y)

Colon after for.

Python

INSERT INTO users VALUES ('data',56)

INSERT INTO users (age, role) VALUES ('data',56);

Specify columns.

SQL

fn render() -> i32 {{ 15 }}

Correct.

Rust

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

Correct.

Shell

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

Correct.

PowerShell

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

Correct.

Java

if data = 76 then print('hello') end

if data == 76 then print('hello') end

Use ==.

Lua

def compute(result): return result + 1

Correct.

Python

let b: Int = 'data'

let b: String = 'data'

Fix type.

Swift

SELECT COUNT(*) FROM items

SELECT COUNT(*) FROM items;

Missing semicolon.

SQL

[x*x for x in data if x > 51]

Correct list comprehension.

Python

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

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

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

Add return type Unit.

Scala

if result > 40 puts 'test'

if result > 40 puts 'test' end

Add 'end'.

Ruby

ArrayList list = new ArrayList();

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

Use generics.

Java

if count = 79

if count == 79

Use ==.

Go

String name = 'output';

Correct.

Dart

if ($foo = 37)

if ($foo == 37)

Use ==.

Perl

while b > 21 b -= 1

while b > 21: b -= 1

Colon missing after while.

Python

User.save();

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

Handle promise.

Node.js

let temp: i32 = "output";

let temp: &str = "output";

Type mismatch.

Rust

function test(item:string){{return item;}} test(60);

function test(item:string){{return item;}} test('value');

Pass correct type.

TypeScript

let item = 28; let item = 95;

let item = 28; item = 95;

Duplicate declaration.

JavaScript

echo 'result'

echo 'result';

Add semicolon.

PHP

Use double quotes.

JSON

bar = 61

bar=61

No spaces.

Shell

println('world')

println("world")

Double quotes.

Scala

x := 4

Correct.

Go

'90' + 88

90 + 88

Avoid string coercion.

JavaScript

lambda x: x+1

Correct lambda.

Python

const index = 96; index = 7;

let index = 96; index = 7;

Cannot reassign const.

JavaScript

let result: number | null = null; result.toFixed(34);

let result: number | null = null; if(result!==null) result.toFixed(34);

Null check.

TypeScript