My method:
def scroll_images
images_all[1..images_all.length]
end
I don't like that I'm calling images_all twice, just wondering if there's a good trick to call self or something similar to make this a little cleaner.
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8
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1what is it that you are trying to do? – xlembouras Jul 18 '14 at 13:31
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get second element to last – neo Jul 18 '14 at 13:34
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You're not "calling" images_all, you're referencing elements of it. Grabbing `images_all.length` is a constant time operation, so what's to refactor? – pjs Jul 18 '14 at 13:40
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2@pjs `images_all` could be a (expensive) method call returning an array – Stefan Jul 18 '14 at 13:42
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@Stefan `images_all` sure looks like an array to me. – pjs Jul 18 '14 at 13:44
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1@pjs `def images_all; query_remote_webserver_for_large_array(); end` – Ajedi32 Jul 18 '14 at 13:51
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@Ajedi32 Easily dealt with by `def scroll_images; result = images_all; result[1..result.length]; end` if that's the case. – pjs Jul 18 '14 at 13:54
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@pjs Well, that's certainly *one* solution. Feel free to post as an answer, or see below for other solutions. – Ajedi32 Jul 18 '14 at 13:57
4 Answers
14
You can get the same result in a clearer way using the Array#drop method:
a = [1, 2, 3, 4]
a.drop(1)
# => [2, 3, 4]
toro2k
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2See also: [`Array#take`](http://ruby-doc.org/core-2.1.2/Array.html#method-i-take) for the other side of the array. – jonathan Jul 18 '14 at 15:35
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12
Use -1 instead of the length:
def scroll_images
images_all[1..-1] # `-1`: the last element, `1..-1`: The second to the last.
end
Example:
a = [1, 2, 3, 4]
a[1..-1]
# => [2, 3, 4]
falsetru
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2
Here is one more way using Array#values_at :-
a = [1, 2, 3, 4]
a.values_at(1..-1) # => [2, 3, 4]
Arup Rakshit
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1
If you're actually modifying the values of images_all i.e. explicitly drop the first element permanently, just use shift:
images_all.shift
konsolebox
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