[FIXED] Python: for a long string where a certain word is repeated, how to identify the first occurrence of the word after a unique word?

Issue

I have a large file that is made up of many blocks of data. For example, two blocks of data would look like:

name1   1234567           comment                           
property1 = 1234567.98765 property2 = 1234567.98765
property3 = 1234567.98765
final

name2   1234568           comment                           
property1 = 987654.321 property2 = 9876543.0
property3 = 1234567.98765
final
...

Problem. I have code to modify one block of data. However, the code results in a string (updated_string) that contains ALL data blocks in the file (the modified data block and all other unmodified data blocks).

Goal. I only want the modified data block in updated_string and then I want to put only updated_string in an external file and leave all other data blocks in the file unmodified.

So far I have figured out from previous posts here how to delete everything from updated_string that comes before the modified data block. For example, if the second data block has been modified, I would do:

mystring = "name2"
begin = string.find(mystring)
string[:begin]

However, I am not able to delete everything after the "final" in the data block I want. I know I can do

mystring2 = "final"
stop = string.find(mystring2)
string[stop:]

but it doesn't identify the particular data block I want. Can anyone please suggest how I might look for the first "final" after name2 so that I can get a string made up of only the data block I want?

Solution

The logic is not fully clear, but assuming you want to find the block between name2 and the first final that follows it, just adapting your current logic should work:

mystring = "name2"
begin = string.find(mystring)
string = string[begin:]         # we drop all before mystring

mystring2 = "final"
stop = string.find(mystring2)   # now we find the stop in the new string
string = string[:stop+len(mystring2)]

Or, better, use the start parameter of str.find:

mystring = "name2"
begin = string.find(mystring)

mystring2 = "final"
# now we only search the stop word after
# the position of the start word (+ its length)
stop = string.find(mystring2, begin+len(mystring))

out = string[begin:stop+len(mystring2)]

Output:

name2   1234568           comment                           
property1 = 987654.321 property2 = 9876543.0
property3 = 1234567.98765
final

Answered By - mozway