Python Remove last char from string and return it

Question

While I know that there is the possibility    gt  gt  gt  a    abc   gt  gt  gt  result   a -1   gt  gt  gt  a   a  -1    Now I also know that strings are immutable and therefore something like this    gt  gt  gt  a pop   c   is not possible   But is this really the preferred way

User · Answer

I decided to go with a for loop and just avoid the item in question  is it an acceptable alternative  new      for item in str      if item    str n           continue     else          new    item

User · Answer

Strings are  immutable  for good reason  It really saves a lot of headaches  more often than you d think  It also allows python to be very smart about optimizing their use  If you want to process your string in increments  you can pull out part of it with split   or separate it into two parts using indices   a    abc  a  result   a  -1   a -1    This shows that you re splitting your string in two  If you ll be examining every byte of the string  you can iterate over it  in reverse  if you wish    for result in reversed a             I should add this seems a little contrived  Your string is more likely to have some separator  and then you ll use split   ans    foo blah etc   for a in ans split

User · Answer

Yes  python strings are immutable and any modification will result in creating a new string  This is how it s mostly done   So  go ahead with it

User · Answer

Not only is it the preferred way  it s the only reasonable way   Because strings are immutable  in order to  remove  a char from a string you have to create a new string whenever you want a different string value   You may be wondering why strings are immutable  given that you have to make a whole new string every time you change a character   After all  C strings are just arrays of characters and are thus mutable  and some languages that support strings more cleanly than C allow mutable strings as well   There are two reasons to have immutable strings  security safety and performance   Security is probably the most important reason for strings to be immutable   When strings are immutable  you can t pass a string into some library and then have that string change from under your feet when you don t expect it   You may wonder which library would change string parameters  but if you re shipping code to clients you can t control their versions of the standard library  and malicious clients may change out their standard libraries in order to break your program and find out more about its internals   Immutable objects are also easier to reason about  which is really important when you try to prove that your system is secure against particular threats   This ease of reasoning is especially important for thread safety  since immutable objects are automatically thread-safe   Performance is surprisingly often better for immutable strings   Whenever you take a slice of a string  the Python runtime only places a view over the original string  so there is no new string allocation   Since strings are immutable  you get copy semantics without actually copying  which is a real performance win   Eric Lippert explains more about the rationale behind immutable of strings  in C   not Python  here

User · Answer

The precise wording of the question makes me think it s impossible   return to me means you have a function  which you have passed a string as a parameter   You cannot change this parameter  Assigning to it will only change the value of the parameter within the function  not the passed in string  E g    gt  gt  gt  def removeAndReturnLastCharacter a           c   a -1          a   a  -1          return c   gt  gt  gt  b    Hello  Gaukler    gt  gt  gt  removeAndReturnLastCharacter b      gt  gt  gt  b      b has not been changed Hello  Gaukler

[python] Python Remove last char from string and return it

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