CODEWITHSUNDEEP
python-3.x
psmith
psmith

Reputation: 1813

fill out missing values for dates

I can pull average currency exchange (EUR->PLN) here: https://api.nbp.pl/api/exchangerates/rates/a/eur/2022-12-01/2022-12-31/?format=json

in the 'rates' field I have values :

"rates":[{"no":"232/A/NBP/2022","effectiveDate":"2022-12-01","mid":4.6892},{"no":"233/A/NBP/2022","effectiveDate":"2022-12-02","mid":4.6850},{"no":"234/A/NBP/2022","effectiveDate":"2022-12-05","mid":4.6898},{"no":"235/A/NBP/2022","effectiveDate":"2022-12-06","mid":4.6995},{"no":"236/A/NBP/2022","effectiveDate":"2022-12-07","mid":4.6968},{"no":"237/A/NBP/2022","effectiveDate":"2022-12-08","mid":4.6976},{"no":"238/A/NBP/2022","effectiveDate":"2022-12-09","mid":4.6821},{"no":"239/A/NBP/2022","effectiveDate":"2022-12-12","mid":4.6912},{"no":"240/A/NBP/2022","effectiveDate":"2022-12-13","mid":4.6945},{"no":"241/A/NBP/2022","effectiveDate":"2022-12-14","mid":4.6886},{"no":"242/A/NBP/2022","effectiveDate":"2022-12-15","mid":4.6843},{"no":"243/A/NBP/2022","effectiveDate":"2022-12-16","mid":4.6934},{"no":"244/A/NBP/2022","effectiveDate":"2022-12-19","mid":4.6886},{"no":"245/A/NBP/2022","effectiveDate":"2022-12-20","mid":4.6804},{"no":"246/A/NBP/2022","effectiveDate":"2022-12-21","mid":4.6648},{"no":"247/A/NBP/2022","effectiveDate":"2022-12-22","mid":4.6551},{"no":"248/A/NBP/2022","effectiveDate":"2022-12-23","mid":4.6364},{"no":"249/A/NBP/2022","effectiveDate":"2022-12-27","mid":4.6558},{"no":"250/A/NBP/2022","effectiveDate":"2022-12-28","mid":4.6938},{"no":"251/A/NBP/2022","effectiveDate":"2022-12-29","mid":4.6969},{"no":"252/A/NBP/2022","effectiveDate":"2022-12-30","mid":4.6899}]

But I don't have values for all days of the month - for example 2022-12-03, 2022-12-04 etc. What I would like to achieve is assign last known value ("mid"), so for example for 2022-12-03 it should be 'mid' value from 2022-12-02, for 2022-12-04 it should also be value from 2022-12-02

This is a piece of code I have to convert abouve response to dictionary: date->mid:

exchange_rates = {}
response = requests.get("https://api.nbp.pl/api/exchangerates/rates/a/eur/2022-12-01/2022-12-31/?format=json")
rates = response.json()['rates']
for i in range(len(rates)):
    exchange_rates[rates[i]['effectiveDate']]=rates[i]['mid']

I have no idea how the algorithm should look like... Any hint is much appreciated.

Upvotes: 1

Views: 42

Answers (1)

Haoliang
Haoliang

Reputation: 1264

We can use a for loop:

exchange_rates = {}
response = requests.get("https://api.nbp.pl/api/exchangerates/rates/a/eur/2022-12-01/2022-12-31/?format=json")
rates = response.json()['rates']
for i in range(len(rates)):
    exchange_rates[rates[i]['effectiveDate']]=rates[i]['mid']

# since 2022-12-01 has a rate, we can use it as the initial value
prev_rate = exchange_rates['2022-12-01']

# use a for loop to go from 2022-12-02 to 2022-12-31
for i in range(2, 32):
    date = '2022-12-' + str(i).zfill(2)
    if date in exchange_rates:
        prev_rate = exchange_rates[date]
    else:
        exchange_rates[date] = prev_rate

Upvotes: 1

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