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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
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Handling huge data
File Handling example from a Well House Consultants training course
More on File Handling [link]

This example is described in the following article(s):
   • Python - fresh examples from recent courses - [link]

Source code: majorcooker.py Module: Y110

""" Handling huge data

Here's a program that reads 30 log files totalling over 1Gbyte of data - that's
over 4 million lines of web server logs - and filters them for lines containing
"Melksham". On an Apple laptop (MacBook Pro) this program took just under 5 seconds
to run.

Note the use of xreadlines to keep the memory profile low - lines are only read in
as they're needed, rather than reading in the whole of an input file in to a huge
list! """


import os
import time

def getplace(where):
        global overall
        fyles = os.listdir(".")
        for fyle in fyles:
                if fyle.startswith("ac_201011"):
                        for line in open(fyle).xreadlines():
                                overall += 1
                                if line.find(where) > -1:
                                        # print "Found one"
                                        yield line

matched = 0
overall = 0
started = time.time()
for access in getplace("Melksham"):
        bits = access.split(" ")
        # print bits[0],bits[6]
        matched += 1
finished = time.time()

print "matches =",matched,"of",overall
print "elapsed time: ",finished - started

""" Output:

wizard:pyoo graham$ python majorcooker.py
matches = 32678 of 4212183
elapsed time: 4.60196805
wizard:pyoo graham$

"""


Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Python
 * Python Programming
Also available on on site courses for larger groups

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Other Examples
This example comes from our "File Handling" training module. You'll find a description of the topic and some other closely related examples on the "File Handling" module index page.

Full description of the source code
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Other resources
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This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

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