How to split the textfile

Question

04-05-1993:1.068

04-12-1993:1.079

04-19-1993:1.079

06-06-1994:1.065

06-13-1994:1.073

06-20-1994:1.079

I have text file for date-year-price for gas and i want to calculate the avg gas prices for year. So i tried to split,

with open('c:/Gasprices.txt','r') as f: 
   fullfile=[x.strip() for x in f.readlines()]
datesprices=[(x.split('-')[0], x.split(':')[1]) for x in fullfile]
print(datesprices)

But I can't get year and price data but data like this.

('04', '1.068'), ('04', '1.079')

please let me know what should i know.

and plus, please let me know how to use split data to calculate the avg price per year using a dictionary if you can.

`x.split('-')[0]` gives you the day, use `x.split('-')[2]` to get the year. — Titouan L, May 10 '22 at 14:31

score 1 · Answer 1 · answered May 10 '22 at 14:41

As it was already mentioned, to get the year you should use a bit more complex split. But your format seems to be very consistent, you could probably go for:

datesprices=[(x[6:10], x[11:]) for x in fullfile]

but how to get average of it? You need to store list for specific year somewhere.

from statistics import mean

my_dict = {} # could be defaultdict too
for year, price in datesprices:
    if year not in my_dict:
        my_dict[year] = []
    my_dict[year].append(price)

for year, prices in my_dict.items():
    print(year, mean(prices))

score 1 · Accepted Answer · answered May 10 '22 at 15:03

1

I see no need to split the input lines as they have a fixed format for the date - i.e., its length is known. Therefore we can just slice.

with open('gas.txt') as gas:
    td = dict()
    for line in gas:
        year = line[6:10]
        price = float(line[11:])
        td.setdefault(year, []).append(price)
    for k, v in td.items():
        print(f'{k} {sum(v)/len(v):.3f}')

Output:

1993 1.075
1994 1.072

Note:

There is no check here for blank lines. It is assumed that there are none and that the sample shown in the question is malformed.

Also, no need to strip the incoming lines as float() is impervious to leading/trailing whitespace

answered May 10 '22 at 15:03

DarkKnight

19,739
3
6
22

I got output well, but i can't understand the code. Can you explain what td=dict() means? – ning May 10 '22 at 15:21
@Seb It assigns a reference to an empty dictionary to a variable named *td*. You may find this interesting:- https://stackoverflow.com/questions/34370599/difference-between-dict-and-set-python – DarkKnight May 10 '22 at 17:49

codester_09 · Answer 3 · 2022-05-10T14:47:58.360

0

TRY THIS


with open('c:/Gasprices.txt','r') as f: 
    fullfile=[x.strip() for x in f.readlines()]
datesprices=[(x.split('-')[0],x.split('-')[-1].split(':')[0], x.split(':')[1]) for x in fullfile]
print(datesprices)

OUTPUT

[('04', '1993', '1.068'), ('04', '1993', '1.079'), ('04', '1993', '1.079'), ('06', '1994', '1.065'), ('06', '1994', '1.073'), ('06', '1994', '1.079')]

OR

with open('c:/Gasprices.txt','r') as f: 
    fullfile=[x.strip() for x in f.readlines()]
datesprices=[(x.split('-')[-1].split(':')[0], x.split(':')[1]) for x in fullfile]
print(datesprices)

OUTPUT

[('1993', '1.068'), ('1993', '1.079'), ('1993', '1.079'), ('1994', '1.065'), ('1994', '1.073'), ('1994', '1.079')]

edited May 10 '22 at 14:47

answered May 10 '22 at 14:34

codester_09

5,622
2
5
27

2

I think the author wants only year and price, in order to get the average price for each year. – lemon May 10 '22 at 14:44
@lemon Thnx, I Added for both. – codester_09 May 10 '22 at 14:48

score 0 · Answer 4 · answered May 10 '22 at 15:01

    txt = ['04-05-1993:1.068', '04-12-1993:1.079', '04-19-1993:1.079', '06-06-1994:1.065', '06-13-1994:1.073', '06-20-1994:1.079']

    price_per_year = {}
    number_of_years = {}
    for i in txt:
      x = txt.split(':')
      Date = x[0]
      Price = x[1]
      year = date.split('-')[2]

      if year ~in price_per_year.keys:
        price_per_year.update({year:Price})
        number_of_years.update({year:1})
      else:
        price_per_year[year] += Price
        number_of_years[year] += 1
 
av_price_1993 = price_per_year[1993] / number_of_years[1993]
av_price_1994
 = price_per_year[1994] / number_of_years[1994]

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How to split the textfile

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