Scanning log file for instability
Additional Python Facilities example from a Well House Consultants training course
More on Additional Python Facilities [link]
Source code: eo2.py Module: Y115
""" This program reads in a data file with a series of lines of the
14-AUG-2007 16:16:04.00, 2.277, -649.20,0.00, 5792.00,237.77, 99.623
and reports on changes from one log line to the next of +- 1% in any
of the data fields after the timestamp. """
# Method to evaluate whether of not a big change occurred
c = float(a) / float(b)
if c > 1.0: c = 1.0 / c
if c < 0.99: return 1
# Define the pattern against which to match the data lines.
# Note the use of string functions to meaningfully build up
# a complex regular expression
date = r"\d\d-...-\d\d\d\d"
time = r"(\d\d):(\d\d):(\d\d.\d\d)"
whitespace = r"\s+"
floater = r"(-?\d+\.\d+)"
wholeline = date + whitespace + time + "," + whitespace + \
floater + "," + whitespace + floater + "," + floater + \
"," + whitespace + floater + "," + floater + "," + \
whitespace + floater
dataline = re.compile(wholeline)
fh = open("eo_monitor.txt","r")
# Grab in all valid data lines and reject short lines, headers, etc
datapool = 
for line in fh.readlines():
ihave = dataline.findall(line)
# Look for major changes in each column in turn
for probcol in range(3,9):
problems = 0
for row in range(1,len(datapool)):
ouch = bigchange(datapool[row][probcol],datapool[row-1][probcol])
problems += 1
print "Problems on column",probcol,"=",problems
# Also a good idea to report total data line count!
print "That's from",len(datapool),"rows"
Learn about this subject
This module and example are covered on the following public courses:
* Learning to program in Python
* Python Programming
* Intermediate Python
Also available on on site courses for larger groups
Books covering this topic
Yes. We have over 700 books in our library. Books covering Python are listed here and when you've selected a relevant book we'll link you on to Amazon to order.
This example comes from our "Additional Python Facilities" training module. You'll find a description of the topic and some other closely related examples on the "Additional Python Facilities" module index page.
Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.
Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
• The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.
Purpose of this website
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.
Web site author
This web site is written and maintained by Well House Consultants.
Conditions of use
Past attendees on our training courses are welcome to use individual examples in the course of their programming, but must check the examples they use to ensure that they are suitable for their job. Remember that some of our examples show you how not to do things - check in your notes. Well House Consultants take no responsibility for the suitability of these example programs to customer's needs.
This program is copyright Well House Consultants Ltd. You are forbidden from using it for running your own training courses without our prior written permission. See our page on courseware provision for more details.
Any of our images within this code may NOT be reused on a public URL without our prior permission. For Bona Fide personal use, we will often grant you permission provided that you provide a link back. Commercial use on a website will incur a license fee for each image used - details on request.
PH: 01144 1225 708225 • FAX: 01144 1225 899360 • EMAIL: firstname.lastname@example.org • WEB: http://www.wellho.net • SKYPE: wellho
PAGE: http://www.wellho.net/resources/ex.php4 • PAGE BUILT: Sun Jan 31 13:04:01 2016 • BUILD SYSTEM: WomanWithCat