Python | Count the elements in a list until an element is a Tuple

In this problem, we need to accept a list. The list can have nested tuples. We need to count the elements in a list until a tuple has been encountered. Examples:

Input : [4, 5, 6, 10, (1, 2, 3), 11, 2, 4]
Output : 4

Input : [4, (5, 6), 10, (1, 2, 3), 11, 2, 4]
Output : 1

Method #1:

In this program we will use the concept of isinstance() to verify whether we are encountering a tuple or not in our path of count. For detailed guide on isinstance() visit isinstance in Python. 

Python3

# Python program to count the items
# until a list is encountered
def Count(li):
    counter = 0
    for num in li:
        if isinstance(num, tuple):
            break
        counter = counter + 1
    return counter

# Driver Code
li = [4, 5, 6, 10, (1, 2, 3), 11, 2, 4]
print(Count(li))

Output:

4

Method #2: Using type() method

Python3

# Python program to count the items
# until a list is encountered
def Count(li):
    counter = 0
    for num in li:
        if type(num) is tuple:
            break
        counter = counter + 1
    return counter

# Driver Code
li = [4, 5, 6, 10, (1, 2, 3), 11, 2, 4]
print(Count(li))

Output

4

Method#3:  Using recursion

Python3

def count_items(li,i):
    if type(li[i]) is tuple or i==len(li):
        return 0
    return 1 + count_items(li,i+1)

li = [4, 5, 6, 10, (1, 2, 3), 11, 2, 4]
print(count_items(li,0))
#This code is contributed by Vinay Pinjala.

Output

4

Time Complexity: O(n)

Auxiliary Space: O(n)