How to make string to dictionary and update values that exist?

问题

I open a file that contains this:

    TransactionNo   Date        CustomerId      PurchasePairs
    -------------   ----        ----------      -------------
    1               09-04-2014  barakobama      potatoes:2.67,sugar:1.98,cereal:5.99,crisps:1.09
    2               11-04-2014  barakobama      parsley:0.76,cereal:3.22
    3               11-04-2014  vladimirputin   bread:0.66,milk:2.87,parsley:1.33

and I want a dictionary like:

{'vladimirputin': {'milk': 2.87, 'parsley': 1.33, 'bread': 0.66}, 
'barakobama': {'parsley': 0.76, 'sugar': 1.98, 'crisps': 1.09, 
'potatoes': 2.67, 'cereal': 9.21}}

I have tried this:

def makeCustomerDictionary(fileNameStr):
    my_dict={}
    file=open(fileNameStr,'r')

    for line in file:
        if line.isdigit():
            line_split=line.split("\t")
            customer_key=set(line_split[2])

The problem is I dont know how to add the price of product "cereal" at barakobama's value.

回答1:

Try this:

#!/usr/bin/env python3

d = {}

with open("in.txt") as i:
    header1 = i.readline()
    header2 = i.readline()

    for line in i:
        fields = line.split()
        d[fields[2]] = dict(item.split(":") for item in fields[3].split(","))

print(d)

Output:

{'vladimirputin': {'milk': '2.87', 'bread': '0.66', 'parsley': '1.33'}, 'barakobama': {'parsley': '0.76', 'cereal': '3.22'}}

If you want floats, change the line to:

d[fields[2]] = dict((item.split(":")[0], float(item.split(":")[1])) for item in fields[3].split(","))

Output:

{'vladimirputin': {'milk': 2.87, 'parsley': 1.33, 'bread': 0.66}, 'barakobama': {'parsley': 0.76, 'cereal': 3.22}}

来源：https://stackoverflow.com/questions/23240008/how-to-make-string-to-dictionary-and-update-values-that-exist