getting-started-files.rst
changeset 217 b595f90016c5
parent 216 7206fe0c03c5
child 218 620a644c0581
--- a/getting-started-files.rst	Wed Oct 06 15:08:52 2010 +0530
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,147 +0,0 @@
-========
- Script
-========
-
-Welcome to the tutorial on getting started with files. 
-
-{{{ Screen shows welcome slide }}}
-
-{{{ Show the outline for this tutorial }}} 
-
-In this tutorial we shall learn to read files, and do some basic
-actions on the file, like opening and reading a file, closing a
-file, iterating through the file line-by-line, and appending the
-lines of a file to a list. 
-
-{{{ switch back to the terminal }}}
-
-As usual, we start IPython, using 
-::
-
-  ipython -pylab 
-
-Let us first open the file, ``pendulum.txt`` present in
-``/home/fossee/``. 
-::
-
-  f = open('/home/fossee/pendulum.txt')
-
-``f`` is called a file object. Let us type ``f`` on the terminal to
-see what it is. 
-::
-
-  f
-
-The file object shows, the file which is open and the mode (read
-or write) in which it is open. 
-
-We shall first learn to read the whole file into a single
-variable. Later, we shall look at reading it line-by-line. We use
-the ``read`` method of ``f`` to read, all the contents of the file
-into the variable ``pend``. 
-::
-
-  pend = f.read()
-
-Now, let us see what is in ``pend``, by typing 
-::
-
-  print pend
-
-We can see that ``pend`` has all the data of file. Type just ``pend``
-to see more explicitly, what it contains. 
-::
-
-  pend
-
-%%1%% Pause the video here and split the variable into a list,
-``pend_list``, of the lines in the file and then resume the
-video. Hint, use the tab command to see what methods the string
-variable has. 
-
-#[punch: should this even be put? add dependency to strings LO,
-where we mention that strings have methods for manipulation. hint:
-use splitlines()]
-::
-
-  pend_list = pend.splitlines()
-
-  pend_list
-
-Now, let us learn to read the file line-by-line. But, before that
-we will have to close the file, since the file has already been
-read till the end. 
-#[punch: should we mention file-pointer?]
-
-Let us close the file opened into f.
-::
-
-  f.close()
-
-Let us again type ``f`` on the prompt to see what it shows. 
-::
-
-  f
-
-Notice, that it now says the file has been closed. It is a good
-programming practice to close any file objects that we have
-opened, after their job is done.
-
-Let us, now move on to reading files line-by-line. 
-
-%%1%% Pause the video here and re-open the file ``pendulum.txt``
-with ``f`` as the file object, and then resume the video.
-
-We just use the up arrow until we reach the open command and issue
-it again. 
-::
-
-  f = open('/home/fossee/pendulum.txt')
-
-Now, to read the file line-by-line, we iterate over the file
-object line-by-line, using the ``for`` command. Let us iterate over
-the file line-wise and print each of the lines. 
-::
-
-  for line in f:
-      print line
-
-As we already know, ``line`` is just a dummy variable, and not a
-keyword. We could have used any other variable name, but ``line``
-seems meaningful enough.
-
-Instead of just printing the lines, let us append them to a list,
-``line_list``. We first initialize an empty list, ``line_list``. 
-::
-
-  line_list = [ ]
-
-Let us then read the file line-by-line and then append each of the
-lines, to the list. We could, as usual close the file using
-``f.close`` and re-open it. But, this time, let's leave alone the
-file object ``f`` and directly open the file within the for
-statement. This will save us the trouble of closing the file, each
-time we open it. 
-
-for line in open('/home/fossee/pendulum.txt'):
-line_list.append(line)
-
-Let us see what ``line_list`` contains. 
-::
-
-  line_list
-
-Notice that ``line_list`` is a list of the lines in the file, along
-with the newline characters. If you noticed, ``pend_list`` did not
-contain the newline characters, because the string ``pend`` was
-split on the newline characters. 
-
-{{{ show the summary slide }}}
-
-That brings us to the end of this tutorial. In this tutorial we
-have learnt to open and close files, read the data in the files as
-a whole, using the read command or reading it line by line by
-iterating over the file object. 
-
-Thank you!   
-