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
x = value	x = 'value'	Quote strings.	Python
let b = 'message'	let b = "message"	Double quotes.	Swift
if a = 45	if a == 45	Use ==.	Ruby
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
int arr[47]; arr[47]=5;	int arr[47]; if(47<47){{}} else arr[47]=5;	Bounds check.	C++
WHERE age = '24'	WHERE age = 24	Don't quote integer.	SQL
if (bar = 26) {{}}	if (bar === 26) {{}}	Use === for equality.	JavaScript
{{'status':'output'}}	{{"status":"output"}}	Use double quotes.	JSON
with open('input.csv') as fh: data = fh.read()	with open('input.csv') as fh: data = fh.read()	Correct.	Python
["result", 13]	["result", 13]	Correct.	JSON
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if (c) console.log('yes') else console.log('no')	if (c) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
if result = 93	if result == 93	Use ==.	Go
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(55);	const http = require('http'); http.createServer((req,res) => res.end('test')).listen(55);	Correct.	Node.js
var x int	var x int	Correct.	Go
assert val > 83	assert val > 83	Correct.	Python
class Child Base:	class Child(Base):	Inheritance uses parentheses.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
System.out.println('value')	System.out.println('value');	Add semicolon.	Java
function handle(val:string){{return val;}} handle(10);	function handle(val:string){{return val;}} handle('data');	Pass correct type.	TypeScript
<a href='https://test.org' target='_blank'>	<a href='https://test.org' target='_blank' rel='noopener'>	Add rel for security.	HTML
if index = 52 then print('hello') end	if index == 52 then print('hello') end	Use ==.	Lua
while read line; do echo $line; done < config.json	while read line; do echo $line; done < config.json	Correct.	Shell
for (int i=0; i<67; i++) {{}}	for (int i=0; i<67; i++) {{}}	Correct.	Java
p {{ color: blue }}	p {{ color: blue; }}	Add semicolon.	CSS
let foo = 70; let foo = 19;	let foo = 70; foo = 19;	Duplicate declaration.	JavaScript
x := 65	x := 65	Correct.	Go
function handle(y) print(y) end	function handle(y) print(y) end	Correct.	Lua
object User {{ def main(args: Array[String]) = println("value") }}	object User {{ def main(args: Array[String]): Unit = println("value") }}	Add return type Unit.	Scala
index = 72	index=72	No spaces.	Shell
if (val = 72)	if (val == 72)	Use ==.	Scala
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(83);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(83, () => console.log('listening'));	Add callback.	Node.js
print 'result'	print('result')	print needs parentheses.	Python
print 'message'	print 'message';	Add semicolon.	Perl
let num: Int = 'result'	let num: String = 'result'	Fix type.	Swift
// comment	/* comment */	Use /* */.	CSS
if ($val = 86) {{}}	if ($val -eq 86) {{}}	Use -eq.	PowerShell
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
<div color=#333>	<div style='color:#333;'>	Use style attribute.	CSS
os.sqrt(73)	import os os.sqrt(73)	Import module first.	Python
local item = 95	local item = 95	Correct.	Lua
echo result test	echo 'result test'	Quote to prevent splitting.	Shell
let y: number \| null = null; y.toFixed(41);	let y: number \| null = null; if(y!==null) y.toFixed(41);	Null check.	TypeScript
val x = 48; x = 77	var x = 48; x = 77	Use var for reassignment.	Scala
{{"value":"test",}}	{{"value":"test"}}	Remove trailing comma.	JSON
int[] values = new int[89]; values[89] = 5;	int[] values = new int[89]; if (89 < values.length) values[89] = 5;	Check bounds.	Java
{{'id':51, 'age' 77}}	{{'id':51, 'age':77}}	Colon missing.	Python
$arr[47]	if ($arr.Count -gt 47) {{ $arr[47] }}	Check bounds.	PowerShell
$y = 23; if ($y = 23) {{}}	$y = 23; if ($y == 23) {{}}	Use ==.	PHP
console.log('result'	console.log('result')	Close parenthesis.	JavaScript
var bar int = 'hello'	var bar string = 'hello'	Type mismatch.	Go
String foo = 'result';	String foo = "result";	Double quotes.	Java
if (item = 15) {{}}	if (item == 15) {{}}	Use ==.	Kotlin
INSERT INTO products VALUES ('message',19)	INSERT INTO products (age, email) VALUES ('message',19);	Specify columns.	SQL
const count;	const count = 38;	Initialize const.	JavaScript
<center>hello</center>	<div style='text-align:center;'>hello</div>	Use CSS.	HTML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
if (num = 19) {}	if (num == 19) {}	Use ==.	Dart
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});	fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});	Better error handling.	Node.js
function render() {{ return {{key:'hello'}} }}	function render() {{ return {{key:'hello'}}; }}	Return object on same line.	JavaScript
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
data[40]	if (data.indices.contains(40)) data[40]	Check index.	Kotlin
$data[50] = 5;	if (isset($data[50])) $data[50] = 5;	Check existence.	PHP
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
arr[31]	if (length(arr) >= 31) arr[31]	Check length.	R
age: value status: hello,	age: value status: hello	Remove comma.	YAML
String name = 'data';	String name = 'data';	Correct.	Dart
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
process	process()	Add parentheses.	Kotlin
[x*x for x in arr if x > 59]	[x*x for x in arr if x > 59]	Correct list comprehension.	Python
const obj:Person = {{name:'value'}};	const obj:Person = {{name:'value', age:62}};	Add missing property.	TypeScript
if val = 64 {{}}	if val == 64 {{}}	Use ==.	Swift
int foo = 'info';	String foo = 'info';	Type mismatch.	Dart
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
#content {{ color: red; }}	#content {{ color: red; }}	Correct.	CSS
switch(c){{ case 9: break; }}	switch(c){{ case 9: break; default: break; }}	Add default case.	Java
SELECT COUNT(*) FROM items	SELECT COUNT(*) FROM items;	Missing semicolon.	SQL
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
disp('world')	disp('world')	Correct.	MATLAB
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
yield val	yield val	Correct yield.	Python
'world' + 19	'world' + 19.to_s	Convert int.	Ruby
data.forEach(function(c) {{ console.log(c); }})	data.forEach((c) => {{ console.log(c); }})	Arrow functions are cleaner.	JavaScript
Write-Host 'test'	Write-Host 'test'	Correct.	PowerShell
match x {{ 1 => {{}} }}	match x {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
<img src='world.jpg'>	<img src='world.jpg' alt='desc'>	Add alt text.	HTML
let item: number = 'test';	let item: string = 'test';	Fix type.	TypeScript
print('test')	print('test')	Correct.	R
.Product {{ color: green; }}	.Product {{ color: green; }}	Correct.	CSS
{{"name":"world" "status":56}}	{{"name":"world", "status":56}}	Add comma.	JSON
println('data')	println("data")	Double quotes.	Scala
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
class = 'world'	class_name = 'world'	'class' is a keyword.	Python
h1 {{ font-size:69px color:green; }}	h1 {{ font-size:69px; color:green; }}	Add semicolon.	CSS
DELETE FROM products WHERE email=71	DELETE FROM products WHERE email=71;	Add semicolon.	SQL
for c in range(64) print(c)	for c in range(64): print(c)	Colon after for.	Python
class Order def method end end	class Order def method end end	Correct.	Ruby
let bar = 55;	let bar = 55;	Correct.	JavaScript

x = value

x = 'value'

Quote strings.

Python

let b = 'message'

let b = "message"

Double quotes.

Swift

if a = 45

if a == 45

Use ==.

Ruby

ArrayList list = new ArrayList();

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

Use generics.

Java

int arr[47]; arr[47]=5;

int arr[47]; if(47<47){{}} else arr[47]=5;

Bounds check.

C++

WHERE age = '24'

WHERE age = 24

Don't quote integer.

SQL

if (bar = 26) {{}}

if (bar === 26) {{}}

Use === for equality.

JavaScript

Use double quotes.

JSON

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

Correct.

Python

["result", 13]

Correct.

JSON

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

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

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

Missing semicolon.

JavaScript

if result = 93

if result == 93

Use ==.

Go

const http = require('http'); http.createServer((req,res) => res.end('test')).listen(55);

Correct.

Node.js

var x int

Correct.

Go

assert val > 83

Correct.

Python

class Child Base:

class Child(Base):

Inheritance uses parentheses.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

System.out.println('value')

System.out.println('value');

Add semicolon.

Java

function handle(val:string){{return val;}} handle(10);

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

Pass correct type.

TypeScript

Add rel for security.

HTML

if index = 52 then print('hello') end

if index == 52 then print('hello') end

Use ==.

Lua

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

Correct.

Shell

for (int i=0; i<67; i++) {{}}

Correct.

Java

p {{ color: blue }}

p {{ color: blue; }}

Add semicolon.

CSS

let foo = 70; let foo = 19;

let foo = 70; foo = 19;

Duplicate declaration.

JavaScript

x := 65

Correct.

Go

function handle(y) print(y) end

Correct.

Lua

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

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

Add return type Unit.

Scala

index = 72

index=72

No spaces.

Shell

if (val = 72)

if (val == 72)

Use ==.

Scala

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(83);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(83, () => console.log('listening'));

Add callback.

Node.js

print 'result'

print('result')

print needs parentheses.

Python

print 'message'

print 'message';

Add semicolon.

Perl

let num: Int = 'result'

let num: String = 'result'

Fix type.

Swift

// comment

/* comment */

Use /* */.

CSS

if ($val = 86) {{}}

if ($val -eq 86) {{}}

Use -eq.

PowerShell

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

Correct.

Java

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

Correct.

PowerShell

Use style attribute.

CSS

os.sqrt(73)

import os os.sqrt(73)

Import module first.

Python

local item = 95

Correct.

Lua

echo result test

echo 'result test'

Quote to prevent splitting.

Shell

let y: number | null = null; y.toFixed(41);

let y: number | null = null; if(y!==null) y.toFixed(41);

Null check.

TypeScript

val x = 48; x = 77

var x = 48; x = 77

Use var for reassignment.

Scala

Remove trailing comma.

JSON

int[] values = new int[89]; values[89] = 5;

int[] values = new int[89]; if (89 < values.length) values[89] = 5;

Check bounds.

Java

Colon missing.

Python

$arr[47]

if ($arr.Count -gt 47) {{ $arr[47] }}

Check bounds.

PowerShell

$y = 23; if ($y = 23) {{}}

$y = 23; if ($y == 23) {{}}

Use ==.

PHP

console.log('result'

console.log('result')

Close parenthesis.

JavaScript

var bar int = 'hello'

var bar string = 'hello'

Type mismatch.

Go

String foo = 'result';

String foo = "result";

Double quotes.

Java

if (item = 15) {{}}

if (item == 15) {{}}

Use ==.

Kotlin

INSERT INTO products VALUES ('message',19)

INSERT INTO products (age, email) VALUES ('message',19);

Specify columns.

SQL

const count;

const count = 38;

Initialize const.

JavaScript

<center>hello</center>

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

Use CSS.

HTML

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

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

Initialize variable.

Java

Correct.

XML

if (num = 19) {}

if (num == 19) {}

Use ==.

Dart

fs.readFile('config.json', (err,data) => {{ if(err) throw err; }});

fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }});

Better error handling.

Node.js

function render() {{ return {{key:'hello'}} }}

function render() {{ return {{key:'hello'}}; }}

Return object on same line.

JavaScript

int* person = nullptr; *person=5;

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

Allocate memory.

C++

data[40]

if (data.indices.contains(40)) data[40]

Check index.

Kotlin

$data[50] = 5;

if (isset($data[50])) $data[50] = 5;

Check existence.

PHP

package main func main() {{}}

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

Import needed.

Go

arr[31]

if (length(arr) >= 31) arr[31]

Check length.

R

age: value status: hello,

age: value status: hello

Remove comma.

YAML

String name = 'data';

Correct.

Dart

list: - item1 - item2

Correct.

YAML

process

process()

Add parentheses.

Kotlin

[x*x for x in arr if x > 59]

Correct list comprehension.

Python

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

const obj:Person = {{name:'value', age:62}};

Add missing property.

TypeScript

if val = 64 {{}}

if val == 64 {{}}

Use ==.

Swift

int foo = 'info';

String foo = 'info';

Type mismatch.

Dart

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

#content {{ color: red; }}

Correct.

CSS

switch(c){{ case 9: break; }}

switch(c){{ case 9: break; default: break; }}

Add default case.

Java

SELECT COUNT(*) FROM items

SELECT COUNT(*) FROM items;

Missing semicolon.

SQL

lambda x: x+1

Correct lambda.

Python

disp('world')

Correct.

MATLAB

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

Correct.

CSS

yield val

Correct yield.

Python

'world' + 19

'world' + 19.to_s

Convert int.

Ruby

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

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

Arrow functions are cleaner.

JavaScript

Write-Host 'test'

Correct.

PowerShell

match x {{ 1 => {{}} }}

match x {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

Add alt text.

HTML

let item: number = 'test';

let item: string = 'test';

Fix type.

TypeScript

print('test')

Correct.

R

.Product {{ color: green; }}

Correct.

CSS

Add comma.

JSON

println('data')

println("data")

Double quotes.

Scala

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

class = 'world'

class_name = 'world'

'class' is a keyword.

Python

h1 {{ font-size:69px color:green; }}

h1 {{ font-size:69px; color:green; }}

Add semicolon.

CSS

DELETE FROM products WHERE email=71

DELETE FROM products WHERE email=71;

Add semicolon.

SQL

for c in range(64) print(c)

for c in range(64): print(c)

Colon after for.

Python

class Order def method end end

Correct.

Ruby

let bar = 55;

Correct.

JavaScript