Extracting multiple data from a single list

Question

I working on a text file that contains multiple information. I converted it into a list in python and right now I'm trying to separate the different data into different lists. The data is presented as following:

CODE/ DESCRIPTION/ Unity/ Value1/ Value2/ Value3/ Value4 and then repeat, an example would be:

P03133 Auxiliar helper un 203.02 417.54 437.22 675.80

My approach to it until now has been:

Creating lists to storage each information:

codes = []
description = []
unity = []
cost = []

Through loops finding a code, based on the code's structure, and using the code's index as base to find the remaining values.

Finding a code's easy, it's a distinct type of information amongst the other data. For the remaining values I made a loop to find the next value that is numeric after a code. That way I can delimitate the rest of the indexes:

• The unity would be the code's index + index until isnumeric - 1, hence it's the first information prior to the first numeric value in each line.

• The cost would be the code's index + index until isnumeric + 2, the third value is the only one I need to store.

• The description is a little harder, the number of elements that compose it varies across the list. So I used slicing starting at code's index + 1 and ending at index until isnumeric - 2.

for i, carc in enumerate(txtl):
    if carc[0] == "P" and carc[1].isnumeric():
        codes.append(carc)
        j = 0
        while not txtl[i+j].isnumeric():
            j = j + 1
        description.append(" ".join(txtl[i+1:i+j-2]))
        unity.append(txtl[i+j-1])
        cost.append(txtl[i+j])

I'm facing some problems with this approach, although there will always be more elements to the list after a code I'm getting the error:

  while not txtl[i+j].isnumeric():
    txtl[i+j] list index out of range.

Accepting any solution to debug my code or even new solutions to problem.

OBS: I'm also going to have to do this to a really similar data font, but the code would be just a sequence of 7 numbers, thus harder to find amongst the other data. Any solution that includes this facet is also appreciated!

Answer 1

A slight addition to your code should resolve this:

        while i+j < len(txtl) and not txtl[i+j].isnumeric():
            j += 1

The first condition fails when out of bounds, so the second one doesn't get checked.

Also, please use a list of dict items instead of 4 different lists, fe:

thelist = []
thelist.append({'codes': 69, 'description': 'random text', 'unity': 'whatever', 'cost': 'your life'})

In this way you always have the correct values together in the list, and you don't need to keep track of where you are with indexes or other black magic...

EDIT after comment interactions: Ok, so in this case you split the line you are processing on the space character, and then process the words in the line.

from pprint import pprint  # just for pretty printing


textl = 'P03133 Auxiliar helper un 203.02 417.54 437.22 675.80'
the_list = []

def handle_line(textl: str):
    description = ''
    unity = None
    values = []
    for word in textl.split()[1:]:
        # it splits on space characters by default
        # you can ignore the first item in the list, as this will always be the code
        # str.isnumeric() doesn't work with floats, only integers. See https://stackoverflow.com/a/23639915/9267296
        if not word.replace(',', '').replace('.', '').isnumeric():
            if len(description) == 0:
                description = word
            else:
                description = f'{description} {word}' # I like f-strings
        elif not unity:
            # if unity is still None, that means it has not been set yet
            unity = word
        else:
            values.append(word)
    return {'code': textl.split()[0], 'description': description, 'unity': unity, 'values': values}

the_list.append(handle_line(textl))

pprint(the_list)    

str.isnumeric() doesn't work with floats, only integers. See https://stackoverflow.com/a/23639915/9267296