Python, Replace all array values with formatted string

Question

I have a numpy array which is built of decimal hours like so:

13.1 13.2 13.3 13.4
14.1 14.2 14.3 14.4
15.1 15.2 15.3 15.4

What I wish to do is convert this array to a time string and then replace all the values in this array with a custom string formatting. I calculate the times like so:

hours = int(time)
minutes = int((time*60) % 60)
seconds = int((time*3600) % 60)

From there the conversion will be done like so to get a time string:

ftime = "{}:{}:{}".format(str(hours), str(minutes), str(seconds))

And lastly I wish to use this formatting rule and replace all the values in the array with it so I get a result like so:

13:06:00 13:12:00 13:18:00 13:24:00
14:06:00 14:12:00 14:18:00 14:24:00
15:06:00 15:12:00 15:18:00 15:24:00

What is the best way to go about this?

Delgan · Accepted Answer · 2017-08-11 09:28:14Z

1

You can simply multiply your array with a numpy.timedelta64() object representing 1 hour.

dates = np.array(hours * np.timedelta64(3600, 's'), dtype=str)

print(dates)
# [['13:06:00' '13:12:00' '13:18:00' '13:24:00']
#  ['14:06:00' '14:12:00' '14:18:00' '14:24:00']
#  ['15:06:00' '15:12:00' '15:18:00' '15:24:00']]

edited Aug 11, 2017 at 9:28

answered Aug 11, 2017 at 9:14

Delgan

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1 Comment

cd123 Over a year ago

This solution is equally valid as the first one however due to the fact that it is a single line solution makes it more preferable to me I'll be using this one so thank you for that.

stamaimer · Accepted Answer · 2017-08-11 09:08:56Z

1

You can use np.vectorize to make a function element wised.

import numpy as np

def format_time(time):
    hours = int(time)
    minutes = int((time*60) % 60)
    seconds = int((time*3600) % 60)
    return "{:02}:{:02}:{:02}".format(hours, minutes, seconds)

format_time = np.vectorize(format_time)

result = format_time(array)

edited Aug 11, 2017 at 9:08

answered Aug 11, 2017 at 8:57

stamaimer

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1 Comment

cd123 Over a year ago

Yep this is exactly what I was looking for thank you.

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