On Saturday, May 25, 2013 08:31:49 pm Martin A. Brown wrote:
> Greetings Tim,
>
> : I'm new to this, just getting through the first Mark Lutz book.
>
> Python objects, either variables your ham below or the string 'spam'
> you entered manually have a specific type. Each and every variable
> or object has a type.
>
> I think you are trying to figure out how you started with a string
> that looked like 'spam' (and Python calls a <type 'str'>) and end up
> with something that looks like:
>
> ['s','p','a','m']
>
> Well, I would encourage you to play with everything at the Python
> prompt. You should be able to enter a tête-à-tête with Python as
> follows. This is what I see when I type 'python' and get an
> interactive console:
>
> Python 2.7.2 (default, Aug 19 2011, 20:41:43) [GCC] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>
>
> Then, I can start playing with variables, strings, lists and all the
> other things that Mark Lutz may mention.
>
> Here's what I actually typed and what Python told me:
> >>> spam = 'spam'
> >>> type(spam)
>
> <type 'str'>
>
> >>> ham = list(spam)
> >>> type(ham)
>
> <type 'list'>
>
> >>> viking = ''.join(ham)
> >>> viking
>
> 'spam'
>
> >>> type(viking)
>
> <type 'str'>
>
> So, the point I'm trying to make here is that you did quite a bit
>
> in just one line, by calling:
> >>> ham=list('spam');ham
>
> Consider playing a bit with the interpreter.
>
> : ham=list('spam');ham
> : ['s','p','a','m']
> :
> : How do I get a string back?
>
> I will now try to annotate my session above, so that you can maybe
> see how I was able to get a string.
>
> >>> spam = 'spam' # -- variable spam now contains string 'spam'
> >>> type(spam)
>
> <type 'str'> # -- and Python tells me it's a string
>
> >>> ham = list(spam) # -- I'm running your command
> >>> type(ham)
>
> <type 'list'> # -- Wait, what!? It's a list?! Oh. Yeah.
>
> >>> viking = ''.join(ham) # -- create a string of the list elements
> >>> viking
>
> 'spam'
>
> >>> type(viking) # -- ah, here's our string!
>
> <type 'str'>
>
> Try out the .join(ham) trick with other strings. For
>
> example...what happens when you try these yourself:
> >>> ham = list('spam')
> >>> '-'.join(ham)
> >>> ':'.join(ham)
> >>> 'B'.join(ham)
> >>> ' '.join(ham)
>
> Hopefully, you see that there's no magic here at all--just that
> you have learned how create a string with all of the elements in a
> list. Try something else for your amusement, as well...
>
> >>> ' '.join(list('frobnitz'))
>
> Does that make sense? Welcome to Python, and Mark Lutz has been
> writing books on Python for almost as long as Python has been
> around. So, good luck and ask questions here. There's quite a
> group here willing to help.
>
> -Martin
The answer was to include ''.join(ham), as in making it a string method
instead of a function, which doesn't exist. Thanks!
For me, picking up Python is a retirement project, so no shortage of time to
learn.
A lot of people tend to be intimidated by Mark Lutz, and so am I, I guess.
There are a lot of books out there that will get one up and running more
quickly, but I get the feeling his is _complete_ instruction, not something
just slopped through. "Learning Python" has taken a long time. I'm not sure
how I'll be able to get through "Programming..." You'll probably see me on
the Core list next year sometime.
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