Super basic python problem (I'm very new and trying to learn python)

[s3a]

Try starting off with a much lighter book than dive into python, the FAQs at the top have a few links for beginners,

here is a more friendly book:

http://www.swaroopch.com/byteofpython/

How to think like a CS with python is good as well:

http://www.greenteapress.com/thinkpython/thinkCSpy/

Thanks! I'm reading byteofpython now!

[pmasiar]

Dive into Python is not for beginner programmers - author assumes experience in other language, and just dives in.

Check wiki in my sig for good links (also linked from sticky FAQ)

[s3a]

I dont understand the following from byteofpython:

You are now able to run the program as long as you know the exact path of the program - but what if
you wanted to be able to run the program from anywhere? You can do this by storing the program in one
of the directories listed in the PATH environment variable. Whenever you run any program, the system
looks for that program in each of the directories listed in the PATH environment variable and then runs
that program. We can make this program available everywhere by simply copying this source file to one
of the directories listed in PATH.
$ echo $PATH
/opt/mono/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/swaroop/bin
$ cp helloworld.py /home/swaroop/bin/helloworld
$ helloworld
Hello World

Can someone explain it to me in further detail please?

[ghostdog74]

that's the problem of not getting familiar with your shell and shell environments before plunging into Python. Explanation here

[LaRoza]

Can someone explain it to me in further detail please?

It doesn't matter what it means; you shouldn't be altering your $PATH without knowledge of it. Just run your programs using absolute paths (or the "." for the CWD)

[s3a]

Well, I guess it is trying to show me how to run my programs regardless of where they are but, cding to directory alone should do it for me [atleast for now], right?

[LaRoza]

Well, I guess it is trying to show me how to run my programs regardless of where they are but, cding to directory alone should do it for me [atleast for now], right?

Right.

[-grubby]

Well, I guess it is trying to show me how to run my programs regardless of where they are but, cding to directory alone should do it for me [atleast for now], right?

I don't get why that wouldn't do it for you every time. If you wanted to run your programs from the command line with one word I assume you'd have to make an sh file in /usr/bin/

[s3a]

Another thing I am not really getting:

Note for Regular Expression Users
Always use raw strings when dealing with regular expressions. Otherwise, a lot of backwhack-
ing may be required. For example, backreferences can be referred to as '\\1' or r'\1'.

I bolded what I don't get. for the first one, I keep thinking the \ makes the first ' diseappear and I am getting confused. Can someone clarify this for me please?

[LaRoza]

Another thing I am not really getting:

Note for Regular Expression Users
Always use raw strings when dealing with regular expressions. Otherwise, a lot of backwhack-
ing may be required. For example, backreferences can be referred to as '\\1' or r'\1'.

There are several ways of writing strings. A "raw" string is just that, a raw string. Nothing is interpreted.

x = "this\nis\nx\n\n"
y = r"this\nis\nx\n\n"

print x
print y