CODEWITHSUNDEEP
pythonnumpydatedatetimeindexing
bull selcuk
bull selcuk

Reputation: 162

Inserting a datetime value within a datetime array Numpy Python

I want to insert the date '2015-12-24 12:51:00' as a datetime value within array as first index how would I be able to do that and get to the Expected Output. to the datetime array a

import numpy as np 
import datetime 

a = np.array(['2017-09-15 07:11:00', '2017-09-15 12:11:00', '2017-12-22 03:26:00',
 '2017-12-22 03:56:00', '2017-12-22 20:59:00', '2017-12-24 12:51:00'], dtype='datetime64[ns]')
datetime = np.insert(a, 0, ('2015-12-24 12:51:00',dtype='datetime64[ns]'))

Error message:

  File "<ipython-input-5-ac3ba1f95707>", line 6
    datetime = np.insert(a, 0, ('2015-12-24 12:51:00',dtype='datetime64[ns]'))
                                                           ^
SyntaxError: invalid syntax

Expected output:

['2015-12-24T12:51:00.000000000' '2017-09-15T07:11:00.000000000'
 '2017-09-15T12:11:00.000000000' '2017-12-22T03:26:00.000000000'
 '2017-12-22T03:56:00.000000000' '2017-12-22T20:59:00.000000000'
 '2017-12-24T12:51:00.000000000']

Upvotes: 0

Views: 1071

Answers (2)

hpaulj
hpaulj

Reputation: 231385

np.array('2015-12-24 12:51:00',dtype='datetime64[ns]') is the correct syntax for creating a datetime array. dtype is a keyword parameter for the np.array function.

There are cases like hstack where you would want to cast this string to the correct dtype first, but insert does take care of that for you. It has a line:

values = array(values, copy=False, ndmin=arr.ndim, dtype=arr.dtype)

Certainly no harm in doing the conversion yourself, just use the correct syntax.

Upvotes: 0

Marius Šomka
Marius Šomka

Reputation: 216

You do not need to specify dtype on insert, that is basically what the error you get is saying. Just do np.insert(a, 0, ('2015-12-24 12:51:00'))

source: https://numpy.org/doc/stable/reference/generated/numpy.insert.html

Upvotes: 1

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