the function that takes an array of size n as its arguments and return the number of array elements which are equal to their index value in array

Question

Below is my code and I'm getting a snytax error at def. Please can anyone help with answer?

def ElementsandIndices(int [] arr, int n):
    count = 0
    for i in range(0, n):
        if arr[i] == i:
            count += 1
    return count

Before asking any questions, you should read a basic Python tutorial. — enzo, Aug 19 '21 at 15:43
"I'm getting a snytax error at def" See how there's a `^` symbol in the error message? Notice where it's pointing? — Karl Knechtel, Aug 19 '21 at 15:59
Thank you. Actually I didn't notice the syntax of array. My bad. — Saurabh Chauhan, Aug 19 '21 at 16:18

score 1 · Answer 1 · edited Aug 19 '21 at 21:38

1

Python is not a strong-typed language, and you have your definitions a little mixed up. Since, by default, variables do not have a type, here's the normal way to define this function:

def ElementsandIndices(arr, n):
    count = 0
    for i in range(0, n):
        if arr[i] == i:
            count += 1
    return count

However, recently typing has become optional, as an additional context assistant to whatever IDE you're using. So if you want to see the types, you can define it like so in Python 3.7+

from typing import List

def ElementsandIndices(arr:List[int], n:int):
    count = 0
    for i in range(0, n):
        if arr[i] == i:
            count += 1
    return count

If your Python version is Python 3.9+, you can use list instead of typing.List:

def ElementsandIndices(arr:list[int], n:int):
    count = 0
    for i in range(0, n):
        if arr[i] == i:
            count += 1
    return count

edited Aug 19 '21 at 21:38

Alan Bagel

818
5
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answered Aug 19 '21 at 15:46

David Culbreth

2,610
16
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The version is Python 3.9+ – Alan Bagel Aug 19 '21 at 15:46
@AlanBagel Type hinting was introduced in Python 3.7 – rioV8 Aug 19 '21 at 16:00
I know, but the `[]` was introduced in Python 3.9. (example: list[int]) – Alan Bagel Aug 19 '21 at 16:01
The version when type hints were introduced was Python 3.5, but the generic builtin data type hinting was introduced in Python 3.9. – Alan Bagel Aug 19 '21 at 16:07

score 0 · Answer 2 · answered Aug 19 '21 at 15:45

0

int [] arr and int n are both not valid python syntax. Just use arr and n instead. If you want to specify the argument's type, use type hints.

answered Aug 19 '21 at 15:45

Alan Bagel

818
5
24

Yeah sure I'll use – Saurabh Chauhan Aug 19 '21 at 16:20

score -1 · Answer 3 · answered Aug 19 '21 at 15:48

-1

It can be done in 1 line

def ElementsandIndices(arr):
    return sum(1 for i,v in enumerate(arr) if v == i)

answered Aug 19 '21 at 15:48

rioV8

24,506
3
32
49

This does not answer the question. The question was saying that there was an syntax error. – Alan Bagel Aug 19 '21 at 15:49
@AlanBagel Where in the question title do you see the words `syntax error` – rioV8 Aug 19 '21 at 15:59
He/she said it was a `snytax error` but it was probably a typo. (syntax error) – Alan Bagel Aug 19 '21 at 16:08

the function that takes an array of size n as its arguments and return the number of array elements which are equal to their index value in array

3 Answers3