In this article, we will explore different methods to find the length of a string without using the len() function in Python. We will look at several techniques like loops, recursion, and generator expressions. These approaches help us manually calculate the length of a string.

Using sum()

sum() with generator expression quickly counts the characters in a string without needing a loop or extra variables. It’s a simple and efficient approach.

s = "GeeksforGeeks"
l= sum(1 for i in s)
print(l)

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Explanation:

• sum(): Sums up the values generated by the expression.
• (1 for i in s):This generates 1 for each character in s.

Using enumerate()

We use enumerate() to go through a list or string while keeping track of the position (index) and the item itself. It makes it easier to work with both the item and its position at the same time.

s = "GeeksforGeeks"
n = 0
for i, char in enumerate(s):  # Unpacking the tuple (index, character)
    n = i + 1
print(n)

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Using for loop

for loop counts characters in a string by going through each one, but requires manual updates, making it a bit less efficient than other methods.

s = "GeeksforGeeks"
l = 0
for char in s:
    l += 1
print(l)

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Using Recursion

Recursion counts characters by repeatedly calling the function until the string is empty. It’s simple but less efficient because of extra function calls.

def fun(s):
    if s == "":  # Base case
        return 0
    else: 
      # add 1 and call fun on the rest of the string
        return 1 + fun(s[1:])

s = "Hello World"
res = fun(s)  
print(res)

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Using iter()

iter() and next()creates an iterator to go through the string and count its characters. It works but is less efficient because it requires handling extra steps and exceptions.

s = "GeeksforGeeks"

# Create an iterator
i = iter(s)  

# Initialize count
l = 0  
try:
    while True:
      
      # Move to next character
        next(i)  
        
        # Increment count
        l += 1
        
 # Stop when iteration finishes
except StopIteration: 
    pass
print(l)

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