Ruby - how to use array with Date.strptime

Question

If I try to convert single String to date it works.

    require 'date'

    a=String.new
    a='20171023'
    puts b=Date.strptime(a,'%Y%m%d')
    puts b.yday()

How can I make it work with an array? I tried this way.

    require 'date'

    a=[20160106, 20132018, 20011221]
    b=a.each{|a| Date.strptime(a, '%Y%m%d').yday()}
    puts b

you tried same variable a withing block, try different one @lezi — Ganesh
– Ganesh, Commented Mar 30, 2018 at 19:17

Sebastián Palma · Accepted Answer · 2018-03-31 23:20:12Z

3

You need to pass a string, instead an integer as you're doing now:

a = ['20160106', '20130218', '20011221']

If you want to store the result of each operation in b, then you can use map instead each:

b = a.map { |date| Date.strptime(date, '%Y%m%d') }

Your second date is invalid, I guess is 20130218.

require 'date'

a = %w[20160106 20130218 20011221]
b = a.map { |date| Date.strptime(date, '%Y%m%d').yday }
p b # [6, 49, 355]

%w[ ... ] is an array of strings, where you avoid using quotes and commas.

When you don't need to pass arguments to a method call, you can avoid parenthesis.

answered Mar 30, 2018 at 19:13

Sebastián Palma

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Comments

Sagar Pandya · Accepted Answer · 2018-03-30 19:18:13Z

1

require 'date'

a = [20160106, 20131018, 20011221]
a.map { |n| (Date.parse n.to_s).yday }

NB the array is different from the OP's, I assume he made a typo of some sort as the second number-date was invalid.

answered Mar 30, 2018 at 19:18

Sagar Pandya

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