[Tutor] capitalize() but only first letter

[Jeff Shannon]

Erik Price wrote:

> Unless it is because every time a concatenation is performed, then a 
> *new* string is created, so you end up with (x + (x - 1)x) strings 
> (because as the parser moves to the next string, it creates a new 
> string to represent the strings concatted thus far, then again with 
> the *next* string, etc). 


This is exactly the case.  When you execute a line of code like, say,

greeting = "Hello" + " " + "world" + "!"

You end up building and then throwing away several strings.  First the 
parser will see "Hello + " " and perform that addition, creating a new 
string "Hello ".  Next it adds *that* string to "world", creating the 
string "Hello world", and throwing away the just-created string "Hello 
".  Then it adds "!",  creating the complete string "Hello world!", and 
throwing away the previous "Hello world".  Each addition beyond the 
first results in a "wasted" string.

By contrast, look at the following almost-equivalent bits of code:

words = ["Hello", " ", "world", "!"]
greeting = ''.join(words)

greeting = '%s%s%s%s' % ("Hello", " ", "world", "!")

Both of these snippets start with the same source strings as the 
addition version.  Each of them creates one other object (a list in the 
first case, a tuple in the second), but no matter how many more words 
are added, there are no other "wasted" objects getting thrown away. 
 Adding 12 words together results in 10 throwaway strings, but joining 
or %-formatting 12 words still results in a single throwaway sequence 
object.

As a minor additional (pun not intended) point, I have a personal 
preference to avoid using + with strings because eventually, that's 
going to lead to code that reads something like "1" + "2", which may 
lead to expecting either a result of "12" or "3".  (Obviously, the real 
result is "12", but if I scanned over that in the middle of a page of 
unfamiliar code, I might not see the obvious... especially since, as I 
understand it, that same code in Perl *would* yield 3!)

Jeff Shannon
Technician/Programmer
Credit International