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Alright, how can you get the behaviour 
that you might have expected? 

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How can you remove one string from the 
start (or end) of another, if it's present? 

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If you're writing code for Python 3.9, two 
new string methods were added by PEP 616. 

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These are the removeprefix 
and removesuffix methods. 

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I'll quickly demonstrate them, but be 
aware that they were added in Python 3.9. 

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If you're using Python version 3.8 or 
earlier, this next bit of code won't work. 

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The removeprefix and removesuffix 
methods were added in Python 3.9. 

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I'll show a more generic way to do the same 
thing, after the demonstration of these 2 methods. 

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Back in IntelliJ
I'll add the code after our existing code, 

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in stripping.py. I'll print a row of 
asterisks again, to separate the output: 

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Run the program, and check the 
last two lines of the output. 

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"Twas", with the apostrophe, has been removed 
from the start of the first line, and "toves" 

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has been removed from the end of the last line.
As I said, these new methods are only available 

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from Python 3.9 onwards. If you want 
your code to run with earlier versions, 

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it's quite easy to create functions that 
perform the same job as these new methods. 

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In fact, sample functions 
have been provided in PEP 616. 

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I'll define the functions 
at the start of our code: 

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Ok, we use the startswith and endswith 
methods, to check that the string we 

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want to remove really is at the start (or 
end) of the string we're removing it from. 

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The functions then use slicing to return 
the string, without the prefix or suffix. 

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To test them, I'll add the 
code at the end of the file. 

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If you're not using Python 3.9 or 
later, the existing code will crash. 

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So I'll comment those lines out 
first, and call our functions instead: 

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That's the removeprefix function. I'll do 
the same for the code to remove the suffix: 

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Run the program:
and we get the same results. 

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"Twas" has been removed in the first of the 
last 2 lines, and "toves" is gone from the last. 

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Ok, that's how you can remove a 
prefix or suffix from a string. 

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As you now know, that's not 
what the strip methods do. 

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They remove all from a sequence of characters, 
until a non-matching character is found. 

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That's the end of this brief digression. In the 
next few videos, we'll see some practical examples 

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of processing data from a text file.
See you in the next video.