help on message splitting code

[akilasekaran]

filename = message.split()[1]  
    f = open(filename[1:])  
        outputdata = f.read()

what is the actual function of code here. first and second lines are hard to figure out :-/

[bvdet]

To begin with, the indentation is wrong.

message is a string object. String method split() is used to break the string into parts using whitespace as a delimiter.

>>> s = "A simple\tstring\nobject."
>>> s
'A simple\tstring\nobject.'
>>> print s
A simple    string
object.
>>> s.split()
['A', 'simple', 'string', 'object.']
>>> 

The code expects element 1 ('simple' in the example above) to be the name of a file object with an unwanted prefix character.

>>> fn = s.split()[1]
>>> fn[1:]
'imple'
>>> 

A file object is created with built-in function open() and read with file object method read().

Really, this is very basic Python. All this information is readily available in the Python documentation. A good place to start is python.org.

[akilasekaran]

i am familiar with split(),open() and read(). but my major concern is about the [1:].. i have neva come across such param with open(filename[1:]).

1.could u temme what [1:] signifies?
2.what is split function followed by [1] mean ?

[bvdet]

@akilasekaran
1. Elements of sequence types are accessed by the index operator (s[i]), slice operator (s[i:j]) and extended slice operator (s[i:j:stride]). Given a string "abcdef":

>>> "abcdef"[1:]
'bcdef'
>>> "abcdef"[:1]
'a'
>>> "abcdef"[1]
'b'
>>> "abcdef"[0:5:2]
'ace'
>>> 

2. String method split() returns a list. Index operator s[1] returns the element at index 1. Note the first element in a list is at index 0.

[dwblas]

Joining and splitting strings http://www.diveintopython.net/native...ing_lists.html and splitting and slicing http://www.freenetpages.co.uk/hp/alan.gauld/tuttext.htm.

[akilasekaran]

oh wow i totally understood it.. thanks dwblas and bvdet :)