Is there any ruby method that I can use to replace two different arrays elements?
For instance, I have these two arrays:
#Before exchange
arr_one = [1,2,3,4,5]
arr_two = ["some", "thing", "new"]
After replacements the elements I am expecting something like this:
#After exchange
arr_one = ["some", "thing", "new"]
arr_two = [1,2,3,4,5]
How can I handle this with or without a ruby method?
You mean, you want to 'exchange' values of local variables? It's quite easy in Ruby:
arr_one, arr_two = arr_two, arr_one
If you need to have the arrays stay put (i.e. the values of the variables not change) and exchange the contents, then this should do:
arr_tmp = arr_one.dup
arr_one.replace(arr_two)
arr_two.replace(arr_tmp)
Related
I have been trying to randomize the values in an ordered array (ex:[0,1,2,3]) in Godot. There is supposed to be a shuffle() method for arrays, but it seems to be broken and always returns "null". I have found a workaround that uses a Fisher-Yates shuffle, but the resulting array is considered "unsorted" by the engine, and therefore when I try to use methods such as bsearch() to find a value by it's position, the results are unreliable at best.
My solution was to create a dictionary, comprised of an array containing the random values I have obtained, merged with a second array of equal length with (sorted) numbers (in numerical order) which I can then use as keys to access specific array positions when needed.
Question made simple...
In GDScript, how would you take 2 arrays..
ex: ARRAY1 = [0,1,2,3]
ARRAY2 = [a,b,c,d]
..and merge them to form a dictionary that looks like this:
MergedDictionary = {0:a, 1:b, 2:c, 3:d}
Any help would be greatly appreciated.
Godot does not support "zip" methodology for merging arrays such as Python does, so I am stuck merging them manually. However... there is little to no documentation about how to do this in GDScript, despite my many hours of searching.
Try this:
var a = [1, 2, 3]
var b = ["a", "b", "c"]
var c = {}
if a.size() == b.size():
var i = 0
for element in a:
c[element] = b[i]
i += 1
print("Dictionary c: ", c)
If you want to add elements to a dictionary, you can assign values to the keys like existing keys.
In Go (golang), is it possible to define a map from strings to arrays, and in each array element I want to store a slice. Like this:
var data = make(map[string][2]Slice[]float64)
Then I want to retrieve my data, something like this:
floatValue0 = data["string-key"][0][#]
floatValue1 = data["string-key"][1][#]
data := map[string][2][]float64{"golang": {[]float64{3.14, 3.15}, []float64{3.12, 3.16}}}
fmt.Println(data["golang"][0][0])
output:
3.14
I'm very new to Ruby so please go easy on me. I have this small function that doesn't want to perform an intersection command. If I go into irb and enter the arrays then set the intersection command like: third_array = array1 & array2, third_array returns the common element. But when I run this snippet through irb, it just returns [ ]. Any suggestions?
class String
define_method(:antigrams) do |word2|
array1 = []
array2 = []
array1.push(self.split(""))
array2.push(word2.split(""))
third_array = array1 & array2
third_array
end
end
After looking at what you have, I think your code boils down to this:
class String
def antigrams(word)
self.chars & word.chars
end
end
"flurry".antigrams("flagrant")
# => ["f", "l", "r"]
If you're calling split('') on a word that's effectively the same as chars, though a lot less efficient. Another mistake was pushing a whole array into an array, which creates a nested array of the form [ [ 'f', 'l', ... ] ]. Since the two resulting array-of-arrays have nothing in common, their inner arrays are different, the & operation returns an empty array.
What you meant was to concatenate the one array to the other, something that can be done with += for example.
Whenever you're curious what's happening, either use irb to try out chunks of code, or p to debug at different points in your method.
I need to take two arrays and return a single array with the combination of the items in them, listing the first items first. Like so:
combinations(["on","in"],["to","rope"])
# => ["onto","onrope","into","inrope"]
I've written a method that does this, but after that, I can't figure out where to go.
Use Array#product:
["on","in"].product(["to","rope"]).map(&:join)
# => ["onto", "onrope", "into", "inrope"]
def combinations(ary1, ary2)
ary1.map {|i| ary2.map {|i2| "#{i}#{i2}" }}.flatten
end
I have two arrays like this:
a = [{'one'=>1, 'two'=>2},{'uno'=>1, 'dos'=>2}]
b = ['english', 'spanish']
I need to add a key-value pair to each hash in a to get this:
a = [{'one'=>1, 'two'=>2, 'language'=>'english'},{'uno'=>1, 'dos'=>2, 'language'=>'spanish'}]
I attempted this:
(0..a.length).each {|c| a[c]['language']=b[c]}
and it does not work. With this:
a[1]['language']=b[1]
(0..a.length).each {|c| puts c}
an error is shown:
NoMethodError (undefined method '[]=' for nil:NilClass)
How can I fix this?
a.zip(b){|h, v| h["language"] = v}
a # => [
# {"one"=>1, "two"=>2, "language"=>"english"},
# {"uno"=>1, "dos"=>2, "language"=>"spanish"}
# ]
When the each iterator over your Range reaches the last element (i.e. a.length), you will attempt to access a nonexisting element of a.
In your example, a.length is 2, so on the last iteration of your each, you will attempt to access a[2], which doesn't exist. (a only contains 2 elements wich indices 0 and 1.) a[2] evaluates to nil, so you will now attempt to call nil['language']=b[2], which is syntactic sugar for nil.[]=('language', b[2]), and since nil doesn't have a []= method, you get a NoMethodError.
The immediate fix is to not iterate off the end of a, by using an exclusive Range:
(0...a.length).each {|c| a[c]['language'] = b[c] }
By the way, the code you posted:
(0..a.length).each {|c| puts c }
should clearly have shown you that you iterate till 2 instead of 1.
That's only the immediate fix, however. The real fix is to simply never iterate over a datastructure manually. That's what iterators are for.
Something like this, where Ruby will keep track of the index for you:
a.each_with_index do |hsh, i| hsh['language'] = b[i] end
Or, without fiddling with indices at all:
a.zip(b.zip(['language'].cycle).map(&:reverse).map(&Array.method(:[])).map(&:to_h)).map {|x, y| x.merge!(y) }
[Note: this last one doesn't mutate the original Arrays and Hashes unlike the other ones.]
The problem you're having is that your (0..a.length) is inclusive. a.length = 2 so you want to modify it to be 0...a.length which is exclusive.
On a side note, you could use Array#each_with_index like this so you don't have to worry about the length and so on.
a.each_with_index do |hash, index|
hash['language'] = b[index]
end
Here is another method you could use
b.each_with_index.with_object(a) do |(lang,i),obj|
obj[i]["language"] = lang
obj
end
#=>[
{"one"=>1, "two"=>2, "language"=>"english"},
{"uno"=>1, "dos"=>2, "language"=>"spanish"}
]
What this does is creates an Enumerator for b with [element,index] then it calls with_object using a as the object. It then iterates over the Enumerator passing in each language and its index along with the a object. It then uses the index from b to find the proper index in a and adds a language key to the hash that is equal to the language.
Please know this is a destructive method where the objects in a will mutate during the process. You could make it non destructive using with_object(a.map(&:dup)) this will dup the hashes in a and the originals will remain untouched.
All that being said I think YAML would be better suited for a task like this but I am not sure what your constraints are. As an example:
yml = <<YML
-
one: 1
two: 2
language: "english"
-
uno: 1
dos: 2
language: "spanish"
YML
require 'yaml'
YAML.load(yml)
#=>[
{"one"=>1, "two"=>2, "language"=>"english"},
{"uno"=>1, "dos"=>2, "language"=>"spanish"}
]
Although using YAML I would change the structure for numbers to be more like language => Array of numbers by index e.g. {"english" => ["zero","one","two"]}. That way you can can access them like ["english"][0] #=> "zero"