File I/O Test

"""
Testing ground for file input and output.
Learning the fun way of course.

== Changelog ==

6/18/13: Started. Timestamp() function created.
6/23/2013: After obnoxious amounts of fail, Timestamp() update works.

"""

# Modules imported. datetime for Timestamp(), re for regex functions.

from datetime import datetime
import re

# Global variables defined.

Now = datetime.now() # really ugly format by default, so I prettied it in Timestamp().
CurrentYear = Now.year
CurrentMonth = Now.month
CurrentDay = Now.day
CurrentHour = Now.hour
CurrentMinute = Now.minute
CurrentSecond = Now.second

# Timestamp function formats and prints current date and time.
# Adds a new line, then the stamp, instead of smashing them together now.

def Timestamp():
    Date = (str(CurrentMonth) + '/' + str(CurrentDay) +  '/' + str(CurrentYear)) # month/day/year
    Time = (str(CurrentHour) + ':' + str(CurrentMinute) + ':' + str(CurrentSecond)) # hour:minute:seconds

    return "Last modified: " + str(Date) + " at " + str(Time)

# Opens the test file to be used; creates it if it doesn't exist in proper directery.
# 'a' is 'append'; adds data from file.write() to the end of file without overwriting.
# 'w' will overwrite the entire freaking file. 'r' is read only, 'r+' is read+write.

Test = open('test.txt', 'r+')

# Checks if test.txt already contains a time stamp. If not, it is appended to the file.

if re.search('Last modified: [\d]+/[\d]+/[\d]+ at [\d]+:[\d]+:[\d]+', Test.read()) == None:
    Test = open('test.txt', 'a')
    Test.write('\n' + str(Timestamp()))
    print("Timestamp added")

Test = open('test.txt', 'r+')

# Holy shit the timestamp updates :O

OriginalFile = Test.read() # Original file before any edits.
# Timestamp() format, to recognize and replace. [\d]+ means "At least one integer here"
TestCompile = re.compile('Last modified: [\d]+/[\d]+/[\d]+ at [\d]+:[\d]+:[\d]+')
# Original file + new Timestamp() edit.
NewFile = re.sub(TestCompile, str(Timestamp()), OriginalFile)
# Clears the entire file, because this appends a copy of entire file even though its not set to append.
Test.write('')
Test.close()
Test = open('test.txt', 'r+')
# Replace entire original file with the new, updated file.
Test.write(NewFile)


"""
ALWAYS make sure file is closed when finished.
Python will write any and all file.write() data to a buffer, then the file,
and only save the changes when file is closed. The code below closes then
double checks closed status.
"""

Test.close()

if Test.closed == False:
    Test.close()