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
{{'value':'message'}}	{{"value":"message"}}	Use double quotes.	JSON
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
for (item in arr)	for (item of arr)	for...in iterates keys.	JavaScript
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if (b = 70) {{}}	if (b == 70) {{}}	Use ==.	Kotlin
for (int i=0; i<22; i++) {{}}	for (int i=0; i<22; i++) {{}}	Correct.	Java
if item = 90	if item == 90	Use ==.	Go
function baz(count:string){{return count;}} baz(97);	function baz(count:string){{return count;}} baz('message');	Pass correct type.	TypeScript
{{"id":"message",}}	{{"id":"message"}}	Remove trailing comma.	JSON
[x*x for x in arr if x > 91]	[x*x for x in arr if x > 91]	Correct list comprehension.	Python
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(49);	const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(49);	Correct.	Node.js
let count: number = 'info';	let count: string = 'info';	Fix type.	TypeScript
<p>value <b>hello</p></b>	<p>value <b>hello</b></p>	Nest properly.	HTML
<div color=blue>	<div style='color:blue;'>	Use style attribute.	CSS
void main() {{ print('hello') }}	void main() {{ print('hello'); }}	Add semicolon.	Dart
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
let val: i32 = "info";	let val: &str = "info";	Type mismatch.	Rust
local result = 34	local result = 34	Correct.	Lua
for i=1,42 do print(i) end	for i=1,42 do print(i) end	Correct.	Lua
<center>output</center>	<div style='text-align:center;'>output</div>	Use CSS.	HTML
SELECT age email FROM users;	SELECT age, email FROM users;	Add comma.	SQL
if (y) console.log('yes') else console.log('no')	if (y) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
x > 55 & b < 14	x > 55 and b < 14	Use 'and' not '&'.	Python
class Product def method end end	class Product def method end end	Correct.	Ruby
div {{ color=red; }}	div {{ color: red; }}	Use colon.	CSS
console.log('message'	console.log('message')	Close parenthesis.	JavaScript
let v=vec![58,90,100]; let first=&v[0]; v.push(93);	let mut v=vec![58,90,100]; let first=v[0]; v.push(93);	Copy instead of reference.	Rust
int data = 'world';	String data = 'world';	Type mismatch.	Dart
if data = 29	if data == 29	Use ==.	MATLAB
{{"age":"test" "title":26}}	{{"age":"test", "title":26}}	Add comma.	JSON
let index: number \| null = null; index.toFixed(85);	let index: number \| null = null; if(index!==null) index.toFixed(85);	Null check.	TypeScript
<user name='value'/>	<user name="value"/>	Double quotes.	XML
process	process()	Add parentheses.	Kotlin
my @arr = (98,32,26);	my @arr = (98,32,26);	Correct.	Perl
arr[77]	if (length(arr) >= 77) arr[77]	Check length.	R
.User {{ color: blue; }}	.User {{ color: blue; }}	Correct.	CSS
[80, 79, 31	[80, 79, 31]	Close bracket.	Ruby
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
class Item {{ int bar; }} obj.bar=5;	class Item {{ public int bar; }} obj.bar=5;	Make field public.	Java
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
// comment	/* comment */	Use /* */.	CSS
cin >> count;	int count; cin >> count;	Declare variable.	C++
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
foo	foo()	Add parentheses.	Swift
val num = 71; num = 13	var num = 71; num = 13	Use var for reassignment.	Scala
const p:Person = {{name:'data'}};	const p:Person = {{name:'data', age:13}};	Add missing property.	TypeScript
let mut c=50; let r1=&mut c; let r2=&mut c;	let mut c=50; {{ let r1=&mut c; }} let r2=&mut c;	Only one mutable borrow.	Rust
<input type='text' value='message'>	<input type='text' value='message' name='name'>	Add name attribute.	HTML
if foo = 54:	if foo == 54:	Use == for comparison.	Python
if (num = 94)	if (num == 94)	Use ==.	Scala
function foo() {{ return {{key:'result'}} }}	function foo() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
result = 92	result=92	No spaces.	Shell
["test", 94]	["test", 94]	Correct.	JSON
object Order {{ def main(args: Array[String]) = println("info") }}	object Order {{ def main(args: Array[String]): Unit = println("info") }}	Add return type Unit.	Scala
WHERE id = '70'	WHERE id = 70	Don't quote integer.	SQL
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
let s1 = String::from("result"); let s2 = s1; println!("{{}}", s1);	let s1 = String::from("result"); let s2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
System.out.println('result')	System.out.println('result');	Add semicolon.	Java
echo hello world	echo 'hello world'	Quote to prevent splitting.	Shell
x := 27	x := 27	Correct.	Go
cin >> index cout << index;	cin >> index; cout << index;	Add semicolon.	C++
if ($y = 53)	if ($y == 53)	Use ==.	Perl
if z = 78 {{}}	if z == 78 {{}}	Use ==.	Swift
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
match num {{ 1 => {{}} }}	match num {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
if (val = 33)	if (val == 33)	Use ==.	R
raise 'value'	raise Exception('value')	Raise needs an exception class.	Python
'hello' + 67	'hello' + 67.to_s	Convert int.	Ruby
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
name: info age: 75	name: info age: 75	Correct.	YAML
int arr[31]; arr[31]=5;	int arr[31]; if(31<31){{}} else arr[31]=5;	Bounds check.	C++
int* user = nullptr; *user=5;	int* user = new int; *user=5;	Allocate memory.	C++
yield z	yield z	Correct yield.	Python
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
let data = 'output'	let data = "output"	Double quotes.	Swift
let str = String::from("data"); let r=&str; str.push_str("!");	let mut str = String::from("data"); let r=&str; println!("{{}}", r); str.push_str("!");	Cannot mutate while borrowed.	Rust
void bar(); int main(){{bar();}}	void bar(); // prototype int main(){{bar();}}	Declare before use.	C++
for val in range(6) print(val)	for val in range(6): print(val)	Colon after for.	Python
$data[49]	if ($data.Count -gt 49) {{ $data[49] }}	Check bounds.	PowerShell
if index = 30 then print('message') end	if index == 30 then print('message') end	Use ==.	Lua
'hello' + 28	'hello' + str(28)	Can't add int to string.	Python
<br></br>	<br>	Self-closing.	HTML
data[96]	if data.indices.contains(96) {{ data[96] }}	Check index.	Swift
const b;	const b = 67;	Initialize const.	JavaScript
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
def compute(): print('message')	def compute(): print('message')	Indent function body.	Python
DELETE FROM orders WHERE status=69	DELETE FROM orders WHERE status=69;	Add semicolon.	SQL
print('output')	print('output')	Correct.	R
with open('config.json') as fh: data = fh.read()	with open('config.json') as fh: data = fh.read()	Correct.	Python
assert bar > 77	assert bar > 77	Correct.	Python
{{'status':24, 'title' 11}}	{{'status':24, 'title':11}}	Colon missing.	Python
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
$b = 15; if ($b = 15) {{}}	$b = 15; if ($b == 15) {{}}	Use ==.	PHP
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
JOIN products ON items.id = products.name	JOIN products ON items.id = products.name	Correct.	SQL
switch(item){{ case 99: break; }}	switch(item){{ case 99: break; default: break; }}	Add default case.	Java
String b = 'message';	String b = "message";	Double quotes.	Java

Use double quotes.

JSON

x = 5; if x > 3, disp('large'), end

Correct.

MATLAB

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

Correct.

CSS

for (item in arr)

for (item of arr)

for...in iterates keys.

JavaScript

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if (b = 70) {{}}

if (b == 70) {{}}

Use ==.

Kotlin

for (int i=0; i<22; i++) {{}}

Correct.

Java

if item = 90

if item == 90

Use ==.

Go

function baz(count:string){{return count;}} baz(97);

function baz(count:string){{return count;}} baz('message');

Pass correct type.

TypeScript

Remove trailing comma.

JSON

[x*x for x in arr if x > 91]

Correct list comprehension.

Python

const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(49);

Correct.

Node.js

let count: number = 'info';

let count: string = 'info';

Fix type.

TypeScript

<p>value <b>hello</p></b>

<p>value <b>hello</b></p>

Nest properly.

HTML

Use style attribute.

CSS

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

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

Add semicolon.

Dart

int main() {{ return 0; }}

Correct.

C++

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

Correct.

PowerShell

let val: i32 = "info";

let val: &str = "info";

Type mismatch.

Rust

local result = 34

Correct.

Lua

for i=1,42 do print(i) end

Correct.

Lua

<center>output</center>

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

Use CSS.

HTML

SELECT age email FROM users;

SELECT age, email FROM users;

Add comma.

SQL

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

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

Missing semicolon.

JavaScript

x > 55 & b < 14

x > 55 and b < 14

Use 'and' not '&'.

Python

class Product def method end end

Correct.

Ruby

div {{ color=red; }}

div {{ color: red; }}

Use colon.

CSS

console.log('message'

console.log('message')

Close parenthesis.

JavaScript

let v=vec![58,90,100]; let first=&v[0]; v.push(93);

let mut v=vec![58,90,100]; let first=v[0]; v.push(93);

Copy instead of reference.

Rust

int data = 'world';

String data = 'world';

Type mismatch.

Dart

if data = 29

if data == 29

Use ==.

MATLAB

Add comma.

JSON

let index: number | null = null; index.toFixed(85);

let index: number | null = null; if(index!==null) index.toFixed(85);

Null check.

TypeScript

Double quotes.

XML

process

process()

Add parentheses.

Kotlin

my @arr = (98,32,26);

Correct.

Perl

arr[77]

if (length(arr) >= 77) arr[77]

Check length.

R

.User {{ color: blue; }}

Correct.

CSS

[80, 79, 31

[80, 79, 31]

Close bracket.

Ruby

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

Correct.

Dart

class Item {{ int bar; }} obj.bar=5;

class Item {{ public int bar; }} obj.bar=5;

Make field public.

Java

lambda x: x+1

Correct lambda.

Python

// comment

/* comment */

Use /* */.

CSS

cin >> count;

int count; cin >> count;

Declare variable.

C++

list: - item1 - item2

Correct.

YAML

foo

foo()

Add parentheses.

Swift

val num = 71; num = 13

var num = 71; num = 13

Use var for reassignment.

Scala

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

const p:Person = {{name:'data', age:13}};

Add missing property.

TypeScript

let mut c=50; let r1=&mut c; let r2=&mut c;

let mut c=50; {{ let r1=&mut c; }} let r2=&mut c;

Only one mutable borrow.

Rust

Add name attribute.

HTML

if foo = 54:

if foo == 54:

Use == for comparison.

Python

if (num = 94)

if (num == 94)

Use ==.

Scala

function foo() {{ return {{key:'result'}} }}

function foo() {{ return {{key:'result'}}; }}

Return object on same line.

JavaScript

result = 92

result=92

No spaces.

Shell

["test", 94]

Correct.

JSON

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

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

Add return type Unit.

Scala

WHERE id = '70'

WHERE id = 70

Don't quote integer.

SQL

Correct.

XML

let s1 = String::from("result"); let s2 = s1; println!("{{}}", s1);

let s1 = String::from("result"); let s2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

System.out.println('result')

System.out.println('result');

Add semicolon.

Java

echo hello world

echo 'hello world'

Quote to prevent splitting.

Shell

x := 27

Correct.

Go

cin >> index cout << index;

cin >> index; cout << index;

Add semicolon.

C++

if ($y = 53)

if ($y == 53)

Use ==.

Perl

if z = 78 {{}}

if z == 78 {{}}

Use ==.

Swift

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

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

Type not in union.

TypeScript

match num {{ 1 => {{}} }}

match num {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

if (val = 33)

if (val == 33)

Use ==.

R

raise 'value'

raise Exception('value')

Raise needs an exception class.

Python

'hello' + 67

'hello' + 67.to_s

Convert int.

Ruby

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

name: info age: 75

Correct.

YAML

int arr[31]; arr[31]=5;

int arr[31]; if(31<31){{}} else arr[31]=5;

Bounds check.

C++

int* user = nullptr; *user=5;

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

Allocate memory.

C++

yield z

Correct yield.

Python

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

let data = 'output'

let data = "output"

Double quotes.

Swift

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

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

Cannot mutate while borrowed.

Rust

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

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

Declare before use.

C++

for val in range(6) print(val)

for val in range(6): print(val)

Colon after for.

Python

$data[49]

if ($data.Count -gt 49) {{ $data[49] }}

Check bounds.

PowerShell

if index = 30 then print('message') end

if index == 30 then print('message') end

Use ==.

Lua

'hello' + 28

'hello' + str(28)

Can't add int to string.

Python

<br>

Self-closing.

HTML

data[96]

if data.indices.contains(96) {{ data[96] }}

Check index.

Swift

const b;

const b = 67;

Initialize const.

JavaScript

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

def compute(): print('message')

Indent function body.

Python

DELETE FROM orders WHERE status=69

DELETE FROM orders WHERE status=69;

Add semicolon.

SQL

print('output')

Correct.

R

with open('config.json') as fh: data = fh.read()

Correct.

Python

assert bar > 77

Correct.

Python

Colon missing.

Python

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

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

Initialize variable.

Java

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

$b = 15; if ($b = 15) {{}}

$b = 15; if ($b == 15) {{}}

Use ==.

PHP

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

Correct.

Java

JOIN products ON items.id = products.name

Correct.

SQL

switch(item){{ case 99: break; }}

switch(item){{ case 99: break; default: break; }}

Add default case.

Java

String b = 'message';

String b = "message";

Double quotes.

Java