CODEWITHSUNDEEP
pythondatetimesubset
Ryan E Lima
Ryan E Lima

Reputation: 25

Python subsetting data by hour and minute, ignoring date

I have a list of image timestamps in the format '20121002_1639' ('%Y%m%d_%H%M')

I want to create a function that takes in a list of these timestamps and excludes images taken between 1500(3:00pm) and 1700 (5:00pm). However When I try to just parse the %H%M portion of the string, it automatically assigns those datetimes to the date 19000101_1500 and 19000101_1700. So I need to create objects which contain just hours and minutes but are not associated with a date.

The pseudo code would be something like this:

import datetime as dt

# example datetime string

datestrings = ['20121002_1639', '20111101_1229', '20160424_1502', '20170328_1100']

Start_time = dt.datetime.strptime('1500', '%H%M')
End_time = dt.datetime.strptime('1700', '%H%M')

good_times = []

for time in datestrings:

    if dt.datetime.strptime(time[9:13], '%H%M') is between(Start_time, End_time):
         continue
    else: 
         good_times.append(time)

Upvotes: 0

Views: 174

Answers (1)

azro
azro

Reputation: 54168

You may use only the time part from the datetime object, for that use the .time() method. So you don't need to parse only a part of the given string, parse all and then take it's time part too

datestrings = ['20121002_1639', '20111101_1229', '20160424_1502', '20170328_1100']

Start_time = dt.datetime.strptime('1500', '%H%M').time()
End_time = dt.datetime.strptime('1700', '%H%M').time()

good_times = []

for time in datestrings:
    if not (Start_time <= dt.datetime.strptime(time, '%Y%m%d_%H%M').time() < End_time):
        good_times.append(time)

print(good_times)  # ['20111101_1229', '20170328_1100']

In fact you coud even do it with basic int comparisons

Start_time = 1500
End_time = 1700
for time in datestrings:
    if not (Start_time <= int(time.split("_")[-1]) < End_time):
        good_times.append(time)

Upvotes: 1

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