python: Replace Variable in VB-Expression-File (.cal) [ArcGis 9.3]

Question

I'm trying to modify a VB-Expression saved in a cal-file:

dim out
if [D19830701]=-9999 then
    out= [D19830501]
else
    out= [D19830701] 
end if
__esri_field_calculator_splitter__
out

with this simple script:

import os, sys
o = open("D:\\Expressionnew.cal","a") #open for append
for line in open("D:\\Expression.cal"):
    line = line.replace("D19830701","D19830801")
    o.write(line + "\n")
o.close()

but all i get is this:

d i m   o u t 


 i f   [ D 1 9 8 3 0 7 0 1 ] = - 9 9 9 9   t h e n 


     o u t =   [ D 1 9 8 3 0 5 0 1 ] 


 e l s e 


     o u t =   [ D 1 9 8 3 0 7 0 1 ]   


 e n d   i f 


 _ _ e s r i _ f i e l d _ c a l c u l a t o r _ s p l i t t e r _ _ 


 o u t 

No Replacement, the script just added "spaces" between every letter.
I want to use this Replacement-Script to fit the cal-file for several calculations i need to make.

Is there maybe a problem with the encoding (unicode?) when the script opens the file?
Maybe somebody has had the same problem ;)
or a nice workaround.

Thank you for reading.... Markus

Answer 1

To demonstrate consider the following test.txt file

"D19830701"

stuff

more stuff

"D19830701"

consider the following Python code

infile = "c:\\temp\\test.txt"
outfile = "c:\\temp\\testout.txt"
input = open(infile,"r")    #open for append
output = open(outfile, "w") #open for write
for line in input.readlines():
  print line
  outline = line.replace("D19830701","D19830801")
  output.write(outline)
input.close()
output.close()

and the resultant output (for the life of me I can't get code single spaced so ignore the extra empty lines).

"D19830801"

stuff

more stuff

"D19830801"

It is safe since it maintains your existing code and readline has been replaced with readlines since a string is an iterable, readlines reads the whole line at once.

Answer 2

Is python a requirement? The .cal files are plain text that can be changed by a text editor. I've used Notepad++ to edit them before. Notepad++, or other free tools, have the capability to replace text strings in a given file, or in files found in a specified folder (all files or a subset that match specific filters).

Answer 3

The saved script is UTF-16. Set the file's encoding in your favorite text editor and you should be able to edit it.