Authors:
Y Daniel Lang
Chapter:
5.recursion
Exercise:
Programming Excercises
Question:15 | ISBN:978013274719 | Edition: 6
Question
(Find the number of uppercase letters in a list) Write a recursive function to return the number of uppercase letters in a list of characters. You need to define the following two functions. The second one is a recursive helper function.
def count(chars):
def countHelper(chars, high):
Write a test program that prompts the user to enter a list of characters in one line and displays the number of uppercase letters in the list.
Answer
Find the number of uppercase letters in a list Program code:
#Recursive function 'count' to count the number of uppercase
#letters in a list of characters.
def count(chars):
return countHelper(chars, len(chars) - 1)
#Recursive helper function 'countHelper' to count the
#number of uppercase letters in a list of characters.
def countHelper(chars, high):
# Base case: If the highest index is less than 0,
#have checked all characters.
if high < 0:
return 0
# Recursive case: Check if the character at the current index is uppercase.
# If it is, increment the count by 1 and recursively call countHelper
# with the previous index.
count = countHelper(chars, high - 1)
if chars[high].isupper():
count += 1
return count
# Prompt the user for input
chars = input("Enter a list of characters (without spaces): ")
# Convert the input string to a list of characters
chars = list(chars)
# Count the number of uppercase letters in the list
uppercase_count = count(chars)
# Display the result
print(f"The number of uppercase letters in the list is: {uppercase_count}")
Executed Output:
Enter a list of characters (without spaces): HelloPythonWorld
The number of uppercase letters in the list is: 3