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Introduction
Do you know how we can find a string's length in python in multiple ways? If not, then don't worry. In this article, we will discuss what exactly len() function is and what are the different methods we can use other than the len() function to calculate the length of the string.
In the example above, we assigned “Hello, Ninjas!” to the variable NinjaString. We also could have used single quotes instead of double quotes, which wouldn’t make any difference, but it is advised to be consistent with using any one of them in your use throughout your code.
We can also use join and count methods for indirectly accessing the length of the string in python. For example,
Code
NinjaString = "Hello, Ninjas!"
separator = ""
count = NinjaString.count(separator) # for counting the number of empty substrings
length = count + 1 # adding one to get the length of the string
print("length of the string is:",length)
You can also try this code with Online Python Compiler
In the above example, the separator is set to an empty string to count the number of occurrences of empty substrings in the provided string. The count() method is used for measuring the number of occurrences of the separator in the given string. This will result in the number of characters in the string and add 1 to it. 1 is added to the count as the count() method only counts the number of separators, not the substrings. Therefore, the length is printed using the print function, which is 16 according to the example.
Join() method
The join method is also used for accessing the length of the strings, almost similar to count() method.
In this example, too, the separator is set to an empty string. The join() method is used for creating a new string (newNinjaString) by joining the character of the original string with the separator.
Join() and Count()
Code
NinjaString = "Hello, Ninjas!"
length = len("".join(NinjaString.split())) - NinjaString.count(' ')
print("length of the string is :",length)
You can also try this code with Online Python Compiler
In the example above, NinjaString is set to the string whose length we wish to calculate. The Split() method is used for splitting the strings in words and the join() method joins them into a single string, but no spaces are included in between. The count() method, counts the number of spaces in the string provided and is subtracted from the length of the new string. Hence, we get the final string.Join() and split() methods remove any spaces in the string, and only the characters are counted. Therefore, this method efficiently provides an accurate number of characters in strings.
Reduce method
This method is used for iterating over the string, and a collection element is provided to the reduce function. Iteration is done over the string character by character, and the count is increased to 1 each time. The function reduces () is used from the functools module in Python.
Code
import functools
def findLen(NinjaString):
return functools.reduce(lambda a,b: a+1, NinjaString, 0)
NinjaString = 'CodingNinjas'
print("Length of the string is:",findLen(NinjaString))
You can also try this code with Online Python Compiler
The reduce function takes three arguments: function, an iterable, and an initial value. The lambda a,b:a+1 adds 1 to the accumulated value ‘a’ for each element in ‘b’ in the given string. The initial value is set to 0. The reduce function is using the lambda function that accumulates the length of the string by adding 1 to the accumulated value for each string element.
Sum() and list Comprehension function
Sum() and list comprehension function can be used to find out the length of a string in the the following way:
Code
NinjaString = "Hello, Ninjas!"
length = sum(1 for char in NinjaString)
print("Length of the string is:", length)
You can also try this code with Online Python Compiler
In the example above, We have used list comprehension for creating a list of ‘1’ for each character in the string, the sum() function is adding up all ‘1’s in the list to give the length f the string. Therefore we get the final length of the string as 14.
Comparison between various Length Function in Python
There are multiple ways to find the length of a string. Below is the comparison between them.
len() function
This is an in-built function, which we have also discussed in the above section. The len() function is used for returning the number of characters in the string.
numpy.char.str_len() function
This function is used for finding the length of the string or array of strings. It gives an array of integers as a result, where each element represents the length of the corresponding string.
Code
import numpy as np
NinjaString = np.array(['Hello', 'Ninjas!'])
print("Length of words in an array:",np.char.str_len(NinjaString))
You can also try this code with Online Python Compiler
This is a built-in method in python that can be used to find the length of the string. The function is called on a string object, which returns the number of characters in the string.
Code
NinjaString = "Hello, Ninjas!"
print("Length of the string is",NinjaString.__len__())
You can also try this code with Online Python Compiler
Can we change the Python string length during runtime?
No, the length of the string cannot be changed during runtime. But a new string can be created by modifying the existing string.
Does the length of a string contain special characters and spaces?
Yes, the length of a string contains special characters and spaces.
What is the Python string length function?
The Python string length function returns the number of characters in the string. In python, we can use len() function in order to get the string length.
Conclusion
We hope this article helped you to understand about Python string length. We have discussed what exactly is len() function and the different methods we can use other than the len() function to calculate the length of the string. Refer to our other articles to better understand strings in python.
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