--- a/getting-started-strings/script.rst Wed Nov 17 23:24:57 2010 +0530
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,191 +0,0 @@
-.. Objectives
-.. ----------
-
-.. At the end of this tutorial, you should know --
-
-.. 1. How to define strings
-.. #. Different ways of defining a string
-.. #. How to concatenate strings
-.. #. How to print a string repeatedly
-.. #. Accessing individual elements of the string
-.. #. Immutability of strings
-
-.. Prerequisites
-.. -------------
-
-.. 1. getting started with ipython
-
-.. Author : Madhu
- Internal Reviewer : Punch
- External Reviewer :
- Language Reviewer : Bhanukiran
- Checklist OK? : <15-11-2010, Anand, OK> [2010-10-05]
-
-Script
-------
-
-{{{ Show the slide containing the title }}}
-
-Hello friends. Welcome to this spoken tutorial on Getting started with
-strings.
-
-{{{ Show the slide containing the outline }}}
-
-In this tutorial, we will look at what we really mean by strings, how
-Python supports the use of strings and some of the operations that can
-be performed on strings.
-
-{{{ Shift to terminal and start ipython }}}
-
-To begin with let us start ipython, by typing::
-
- ipython
-
-on the terminal
-
-So, what are strings? In Python anything within either single quotes
-or double quotes or triple single quotes or triple double quotes are
-strings.
-
-{{{ Type in ipython the following and read them as you type }}}::
-
- 'This is a string'
- "This is a string too'
- '''This is a string as well'''
- """This is also a string"""
- 'p'
- ""
-
-Note that it really doesn't matter how many characters are present in
-the string. The last example is a null string or an empty string.
-
-Having more than one control character to define strings is handy when
-one of the control characters itself is part of the string. For
-example::
-
- "Python's string manipulation functions are very useful"
-
-By having multiple control characters, we avoid the need for
-escaping characters -- in this case the apostrophe.
-
-The triple quoted strings let us define multi-line strings without
-using any escaping. Everything within the triple quotes is a single
-string no matter how many lines it extends::
-
- """Having more than one control character to define
- strings come as very handy when one of the control
- characters itself is part of the string."""
-
-We can assign this string to any variable::
-
- a = 'Hello, World!'
-
-Now 'a' is a string variable. String is a collection of characters. In
-addition string is an immutable collection. So all the operations that
-are applicable to any other immutable collection in Python works on
-string as well. So we can add two strings::
-
- a = 'Hello'
- b = 'World'
- c = a + ', ' + b + '!'
-
-We can add string variables as well as the strings themselves all in
-the same statement. The addition operation performs the concatenation
-of two strings.
-
-Similarly we can multiply a string with an integer::
-
- a = 'Hello'
- a * 5
-
-gives another string in which the original string 'Hello' is repeated
-5 times.
-
-Following is an exercise that you must do.
-
-%% %% Obtain the string ``%% -------------------- %%`` (20 hyphens)
- without typing out all the twenty hyphens.
-
-Please, pause the video here. Do the exercise and then continue.
-
-::
-
- s = "%% " + "-"*20 + " %%"
-
-Let's now look at accessing individual elements of strings. Since,
-strings are collections we can access individual items in the string
-using the subscripts::
-
- a[0]
-
-gives us the first character in the string. The indexing starts from 0
-for the first character and goes up to n-1 for the last character. We
-can access the strings from the end using negative indices::
-
- a[-1]
-
-gives us the last element of the string and
-::
-
- a[-2]
-
-gives us second element from the end of the string
-
-Following is an exercise that you must do.
-
-%% %% Given a string, ``s = "Hello World"``, what is the output of::
-
- s[-5]
- s[-10]
- s[-15]
-
-Please, pause the video here. Do the exercise and then continue.
-
-::
-
- s[-5]
-
-gives us 'W'
-::
-
- s[-10]
-
-gives us 'e' and
-::
-
- s[-15]
-
-gives us an ``IndexError``, as should be expected, since the string
-given to us is only 11 characters long.
-
-Let us attempt to change one of the characters in a string::
-
- a = 'hello'
- a[0] = 'H'
-
-As said earlier, strings are immutable. We cannot manipulate a
-string. Although there are some methods which let us manipulate
-strings, we will look at them in the advanced session on strings. In
-addition to the methods that let us manipulate the strings we have
-methods like split which lets us break the string on the specified
-separator, the join method which lets us combine the list of strings
-into a single string based on the specified separator.
-
-{{{ Show summary slide }}}
-
-This brings us to the end of another session. In this tutorial session
-we learnt
-
- * How to define strings
- * Different ways of defining a string
- * String concatenation and repetition
- * Accessing individual elements of the string
- * Immutability of strings
-
-{{{ Show the "sponsored by FOSSEE" slide }}}
-
-This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India
-
-Hope you have enjoyed and found it useful.
-Thank you!
-