Reading and analyzing data from a text file:
My gentle introduction to writing a Python script. A script I needed to read in a log file and extract all inkjet printhead temperature values in Celcius recorded for the duration of the print run. Very simple. Open file and read each line of text, finding those whose string contains “Temperature”, for those that do strip away “Printhead Temperature (Celcius) = ” and strip away the newline character, leaving us with the raw temperature value printed on each line.
import string
file = open( 'C:\\Arrayjet\\MyLogfile.txt' )
for line in file.readlines():
s = line
if string.find( s, "Temperature" ) != -1:
k = string.strip( s, "Printhead Temperature (Celcius) = " )
k = string.strip( k, "\n" )
print k
Raise a set of numbers to the power of 2; print the result:
import math for i in range(0, 32): print int( math.pow( 2, i ) )
Reading / Writing from text files :
# open a file for reading, get the whole string linestring = open( "C:\Text.txt", 'r' ).read() # open text file for writing outfile = open( "C:\OutText.txt", 'w' ) # output string to output file outfile.write( linestring )
Read data from Excel, modify data and output to text file:
If you don’t already have it, download and install Python package for extracting data from Excel files. This is an example of making a small modification to all entries in a large tab-separated file, in order to make it compatible with other software I am using.
import xlrd import string # open spreadsheet wb = xlrd.open_workbook( "C:\Arrayjet\Daryl Williams\cb5vance9thsept.xls" ) # get the first xls sheet by index sh = wb.sheet_by_index( 0 ) # open up a text file for writing outfile = open( "C:\Arrayjet\Daryl Williams\Out.txt", 'w' ) # iterate through rows and print their values. Add extra tab after first column # and output all this to text file “Out.txt” for rownum in range( sh.nrows ) : col0 = sh.cell( rownum, 0 ).value col1 = sh.cell( rownum, 1 ).value col2 = sh.cell( rownum, 2 ).value col3 = sh.cell( rownum, 3 ).value linestring = col0 + "\t" + col1 + "\t" + col2 + "\t" + col3 + "\n" outfile.write( linestring )
