Convert/split YYYYMMDD into data consisting of year, month, day in python

Question

My data looks like this and I need to use only the days. How can I split the int YYYYMMDD into three integers YYYY, MM, DD

YYYYMMDD
20170301
20170302
20170303
20170304
20170305

Answer 1

Edit: Just noted OP only wanted the day. If you don't care to interpret the string as a datetime object, @chrisz's answer is simpler.

For just the day:

my_date= '20170301'
my_day = int(my_date[-2:])

The [-2:] represents slicing the string, from the second last character to the end, which returns '01', and is then converted to an integer by int().

Original answer:

If you want to interpret the date as a datetime object for other references, use strptime from datetime module.

INPUT:

import datetime
my_str = '20170301'
my_date = datetime.datetime.strptime(my_str,'%Y%m%d')
print(my_date)
print(type(my_date))

OUTPUT:

2017-03-01 00:00:00
<class 'datetime.datetime'>

Now you can interpret the datetime object. You can now grab the year, month, day easily:

my_day = b.day
my_month = b.month
my_year = b.year
print(my_year, my_month, my_day)
print(type(my_year), type(my_month), type(my_day))

Returns:

2017 3 1
<class 'int'> <class 'int'> <class 'int'>

Answer 2

You can subscript strings like so, so just convert your int to a string, and do this, and then convert back using int() and str()

data = str(20170305)

year = int(data[0:4])
month = int(data[4:6])
day = int(data[6:8])

print(year, month, day)

Output:

2017 3 5 

If you actually want to convert this into a date object, @Idlehands's answer will help you.

If you just need the day, you can also do:

data = 20170305
day = abs(data) % 100
print(day)

Output:

5

Just note that this will not preserve the DD format, and you would have to account for that.

Answer 3

Using a for loop, you could extract year, month, and day, and convert them to integers.

data = ['20170301',
        '20170302',
        '20170303',
        '20170304',
        '20170305']

yyyy_mm_dd = []

for date in data:
    year = int(date[:4])
    month = int(date[4:6])
    day = int(date[6:])
    yyyy_mm_dd.append([year, month, day])

print(yyyy_mm_dd)
# [[2017, 3, 1], [2017, 3, 2], [2017, 3, 3], [2017, 3, 4], [2017, 3, 5]]

Use a list comprehension to extract days from yyyy_mm_dd:

days = [sub[-1] for sub in yyyy_mm_dd]

print(days)
# [1, 2, 3, 4, 5]