在 python 操作行中读取文件

Question

So i have this file:

#Name, IdNb, Age, Direct, Fitness, Immune:
Bruno, cvd443, 37, <cvd221, cvd343, cvd245, cvd556>, 3, Yes 
Manuela, cvd256, 72, <cvd173, cvd132>, 4, No

I want to read it and create a list of lists and i coded this:

def readSocialNetwork (filename):

    inFile = open (filename, "r")
    fileContent = inFile.readlines()
    fileContent = fileContent [1:]

    socialNetworkList = []

    for line in fileContent:

        socialDetails = line.strip().split (", ")
        socialNetworkList.append(socialDetails) #socialNetworkObject

    return socialNetworkList

And it returns this:

[['Bruno', 'cvd443', '37', '<cvd221', 'cvd343', 'cvd245', 'cvd556>', '3', 'Yes'], ['Manuela', 'cvd256', '72', '<cvd173', 'cvd132>', '4', 'No']]

The only problem is i want the info between < > to be all together inside the same string, but because of the split function it doesnt happen. Any ideas on how to solve this?

Thanks for the help!

Answer 1

You can use the csv library to parse the comma-separated values (csv) file:

import csv


def read_csv(filename):
    with open(filename) as stream:
        next(stream)  # skip the first line
        csv_reader = csv.reader(stream, skipinitialspace=True)
        return list(csv_reader)


for stuff in read_csv("data.csv"):
    print(stuff)

Output:

['Bruno', 'cvd443', '37', '<cvd221', 'cvd343', 'cvd245', 'cvd556>', '3', 'Yes ']
['Manuela', 'cvd256', '72', '<cvd173', 'cvd132>', '4', 'No']

Update

My initial solution was dead wrong. In my revised solution, I added quotes around the < and >:

import csv


def translate(lines):
    for line in lines:
        yield line.replace('<', '"<').replace('>', '>"')

def read_csv(filename):
    with open(filename) as stream:
        next(stream)  # Skip the first line
        stream = translate(stream)
        csv_reader = csv.reader(stream, skipinitialspace=True)
        return list(csv_reader)


for stuff in read_csv("data.csv"):
    print(stuff)

Output:

['Bruno', 'cvd443', '37', '<cvd221, cvd343, cvd245, cvd556>', '3', 'Yes ']
['Manuela', 'cvd256', '72', '<cvd173, cvd132>', '4', 'No']

The translate function takes a bunch of lines, then add the quotes around the < and >.

Answer 2

The easiest solution is to use a standardized file format such as CSV . If you can't do that, you'll need a regular expression. Here's on that works on your sample input:

(?:\s|^)(?:([^<].*?)(?:,|\n|$)|<(.*?)>(?:,|\n|$))

Here's how it works:

• (?:\s|^) matches the beginning of the input or a whitespace token (ignored)
• (?: opens a non-capturing group that's going to contain our two match options
• ([^<].*?)(?:,|\n|$) matches and captures content that's not surrounded by <> , and is followed by a comma, newline, or string end.
• | or, since our non-capturing group has two options
• <(.*?)>(?:,|\n|$) matches and captures content that's surrounded by <> , and is followed by a comma, newline, or string end.
• ) closes the non-capturing group containing the new options.

Note this doesn't handle comment lines, I'll leave that to you to figure out as I'm a strong believer in being able to work with your own code base.