#----------------------------------------------------------------------
# Techniques for reading text from files.
#
# Copyright (C) April 26, 2017 -- Dr. William T. Verts
#----------------------------------------------------------------------

#----------------------------------------------------------------------
# Technique #1: Read the entire file in as a single string
# The characters are then counted into a dictionary.
#----------------------------------------------------------------------

def Main1():
    Filename = pickAFile()             # Get a file name
    
    Infile = open(Filename, "r")       # Open a file handle for reading
    X = Infile.read()                  # Read entire file in as one string
    Infile.close()                     # Close file handle
    
    print X                            # Print the string (the whole file)
    print len(X)                       # Prints the number of characters in the string X

    D = {}                             # Build a dictionary containing the counts
    for CH in X:                       # of every character in the string/file.
        if not (CH in D): D[CH] = 0    # First check to see if the character is in the dictionary, initialize if not
        D[CH] = D[CH] + 1              # Increase the count
                                       #
    print D                            # Print the result
    
    return
    
#----------------------------------------------------------------------
# Technique #2: Read file into a list, one line of text per list entry.
# Note that line-breaks (\n) are present at the end of each string.
#----------------------------------------------------------------------

def Main2():
    Filename = pickAFile()             # Get a file name
    
    Infile = open(Filename, "r")       # Open a file handle for reading
    X = Infile.readlines()             # Read file in as list of strings (one line per string, including newline characters)
    Infile.close()                     # Close file handle
    
    print X                            # Print the list
    print len(X)                       # Print the number of items in the list (the number of lines in the file)

    return

#----------------------------------------------------------------------
# Technique #3: Same as Technique #2, except that trailing line-breaks
# are stripped out.  File is then capitalized and written out to a
# new file.
#----------------------------------------------------------------------

import string

def Main3():
    Filename = pickAFile()             # Get a file name
    
    Infile = open(Filename, "r")       # Open a file handle for reading
    X = Infile.readlines()             # Read file in as list of strings (one line per string), including newline characters
    Infile.close()                     # Close file handle
    
    X = [L.rstrip("\n") for L in X]    # Strip off trailing newlines
    
    X = [string.upper(L) for L in X]   # Capitalize all the strings (could be combined with previous statement)
    
    print X                            # Print the list
    print len(X)                       # Print the number of items in the list (the number of lines in the file)

    Dot = string.find(Filename,".")                     # Use string slicing to insert "NEW"
    Filename = Filename[:Dot] + "NEW" + Filename[Dot:]  # right before the dot in the filename.

    Outfile = open(Filename,"w")       # Open a file handle for new file for writing
    for L in X:                        #
        Outfile.write(L+"\n")          # Write out each line to the file, restoring line breaks
    Outfile.close()                    # Close file handle
    
    return