How use line.rstrip() in Python?

Question

I am trying to read a file using Python. This the my file test.txt:

Hello World
My name is Will
What's your name?

This is my python code:

fhand = open('test.txt')
for line in fhand:
    line.rstrip()
    print line

No matter whether I use line.rstrip() , The output is always as following:

Hello World

My name is Will

What's your name?

How can I output without the empty line using rstrip() like this?

Hello World
My name is Will
What's your name?

Answer 1

line.rstrip() does not change the old variable, it returns the stripped value of the old variable and you have to reassign it in order for the change to take effect, like:

line = line.rstrip()

Otherwise the line isn't changed and it uses the old line instead of the stripped one.

Answer 2

 line.rstrip()

Here you do get the stripped string, but you are not storing the value.

Replace line.rstrip() with line = line.rstrip()

Let's see the demo:

>>> string = "hello    "
>>> string.rstrip()
'hello'
>>> string
'hello    '
>>> string = string.rstrip()
>>> string
'hello'
>>> 

Answer 3

Strings in python (and other languages) are immutable, meaning once created they cannot be modified, so essentially line.rstrip() creates a new string instance with the stripped content.

You can set your variable to it before printing:

line = line.rstrip()

Same goes for other string functions eg: strip, lowercase, uppercase etc. and slicing eg: line[1:]

To find out what other types behave this way check out: https://en.wikibooks.org/wiki/Python_Programming/Data_Types#Mutable_vs_Immutable_Objects