Some basic questions

[Irmen de Jong]

Brian Christopher Robinson wrote:
> I just began writing Python today and have a few basic questions:
> 
> How can I read a single character from the standard input without consuming 
> any more input?

There is only a platform specific way to do this, AFAIK.
Look in the cookbook: 
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/134892

> Is there any way to write a boolean function?  I wanted to write a simple 
> is_alpha function (which may be in the standard library but I'm leanring), 
> and this is what I came up with:
> 
> def is_alpha(c) :
>     letters = re.compile("[a-zA-Z]")
>     return letters.match(c)
> 
> Instead of checking for true or false I check to see if None is returned, 
> but that seems a little kludgy.

Just use a boolean expression in your return statement, in your example
this would be:
  def is_alpha(c) :
      letters = re.compile("[a-zA-Z]")
      return letters.match(c) is not None

(Note that recompiling the regex on each function invocation isn't
very efficient, but that's another story).

> How can I print to standard out without printing a newline?  It seems that 
> the print statement always adds a newline and I haven't found any other 
> outputting functions yet.

Use a comma at the end of your print statement, like:
   print "blabla",

Or use the file object sys.stdout:
   sys.stdout.write("blabla")


--Irmen