Question

I’ve got a little script which is not working nicely for me, hope you can help and find the problem.

I have two starting files:
traveltimes: contains the lines I need, it’s a column file (every row has just a number). The lines I need are separated by a line which starts with 11 whitespaces

header lines: contains three header lines

output_file: I want to get 29 files (STA%s). What’s inside? Every file will contain the same header lines after which I want to append the group of lines contained in the traveltimes file (one different group of lines for every file). Every group of lines is made by 74307 rows (1 column)

So far this script creates 29 files with the same header lines but then it mixes up everything, I mean it writes something but it’s not what I want.

Any idea????

def make_station_files(traveltimes, header_lines):
"""Gives the STAxx.tgrid files required by loc3d"""
sta_counter = 1
with open (header_lines, 'r') as file_in:
    data = file_in.readlines()
    for i in range (29):
        with open ('STA%s' % (sta_counter), 'w') as output_files: 
            sta_counter += 1
            for i in data [0:3]:
                values = i.strip()                   
                output_files.write ("%s\n\t1\n" % (values))
                with open (traveltimes, 'r') as times_file:
                    #collector = []
                    for line in times_file:
                            if line.startswith ("            "):
                                break
                            output_files.write ("%s" % (line))

Answer 1

Suggestion:

• Read the header rows first. Make sure this works before proceeding. None of the rest of the code needs to be indented under this.
• Consider writing a separate function to group the traveltimes file into a list of lists.
• Once you have a working traveltimes reader and grouper, only then create a new STA file, print the headers to it, and then write the timegroups to it.

Build your program up step-by-step, making sure it does what you expect at each step. Don’t try to do it all at once because then you won’t easily be able to track down where the issue lies.

My quick edit of your script uses itertools.groupby() as a grouper. It is a little advanced because the grouping function is stateful and tracks it state in a mutable list:

def make_station_files(traveltimes, header_lines):
    'Gives the STAxx.tgrid files required by loc3d'

    with open (header_lines, 'r') as f:
        headers = f.readlines()

    def station_counter(line, cnt=[1]):
        'Stateful station counter -- Keeps the count in a mutable list'
        if line.strip() == '':
            cnt[0] += 1
        return cnt[0]

    with open(traveltimes, 'r') as times_file:
        for station, group in groupby(times_file, station_counter):
            with open('STA%s' % (station), 'w') as output_file:
                for header in headers[:3]:
                    output_file.write ('%s\n\t1\n' % (header.strip()))
                for line in group:
                    if not line.startswith('           '):
                        output_file.write ('%s' % (line)) 

This code is untested because I don’t have sample data. Hopefully, you’ll get the gist of it.