The `*` operator as used in Ruby. So called because it looks like an insect that's splatted on a windscreen.
The * operator as used in Ruby. So called because it looks like an insect that's splatted on a windscreen.
Questions tagged [splat]
166 questions
5
votes
3 answers
What does this mean in Ruby language?
Run the following code,
a = [1, 2, 3, 4, 5]
head, *tail = a
p head
p tail
You will get the result
1
[2, 3, 4, 5]
Who can help me to explain the statement head,*tail = a, Thanks!
Just a learner
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votes
3 answers
ReactiveUI Dependency Injection Constructor
I am using the built in dependency injector/splat injector inside ReactiveUI.
I have constructors where I want to pass along their applicable data repository.
In other frameworks it just uses reflections with the interfaces, and uses the GetServices…
Glenn Watson
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5
votes
2 answers
splat over JavaScript object (with new)?
How do I splat across objects without using ECMA6 features?
Attempt
function can(arg0, arg1) {
return arg0 + arg1;
}
function foo(bar, haz) {
this.bar = bar;
this.haz = haz;
}
myArgs = [1,2];
With can I can just do:
can.apply(this,…
A T
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5
votes
4 answers
Why is splat argument in ruby not used all the time?
I know splat arguments are used when we do not know the number of arguments that would be passed. I wanted to know whether I should use splat all the time. Are there any risks in using the splat argument whenever I pass on arguments?
poorvank
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5
votes
2 answers
Making a Hash from an array - how does this work?
fruit = ["apple","red","banana","yellow"]
=> ["apple", "red", "banana", "yellow"]
Hash[*fruit]
=> {"apple"=>"red", "banana"=>"yellow"}
Why does the splat cause the array to be so neatly parsed into the Hash?
Or, more precisely, how does the…
uzo
- 2,821
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5
votes
3 answers
Why is the splat used inside an array definition here?
def initialize(apps, catch=404)
@apps = []; @has_app = {}
apps.each { |app| add app }
@catch = {}
[*catch].each { |status| @catch[status] = true }
end
In this method from Rack::Cascade, what purpose does the splat(*) serve in the [*catch]…
uzo
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4
votes
1 answer
Is it effcient to use a splat operator in a constructor?
In a constructor, it often happens that you want to turn the arguments into instance variables. A naive way to do it is:
class A
def initialize a, b, c
@a, @b, @c = a, b, c
end
end
but an easier way is:
class A
def initialize…
sawa
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4
votes
2 answers
How can I splattify an anonymous object so I can use &method on it?
I'm wanting to use the &method(:method_name) idiom when there's more than one object required by method_name. Can I do this under Ruby 1.9?
For example, if I've got
def move_file(old_filename, new_filename)
STDERR.puts "Moving…
Andrew Grimm
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4
votes
2 answers
How to print a list using splat-operator (*) without spaces
I'm trying to understand splat-operators in python. I have a code:
word = ['s', 't', 'a', 'c', 'k', 'o', 'v', 'e', 'r', 'f', 'l', 'o', 'w']
print(*word)
output:
s t a c k o v e r f l o w
I can't assign *word to some variable to check its type or…
Pavel Antspovich
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4
votes
2 answers
Why is Hash#merge using the splat operator returning an Array of Arrays of Hashes instead of an Array of Hashes?
TL;DR
I solved the problem through trial and error, but there's clearly a gap in my understanding of how the splat operator and pp method are consistently giving me a different object than the one I think I have. I'd like to understand that gap, and…
Todd A. Jacobs
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4
votes
1 answer
Passing an empty hash through double splat in ruby
The idea is similar to what you would do with a decorator in python, I don't know what arguments the method takes so i'm passing *args, **kwargs as a general case
The problem arises when I want to pass an empty hash as kwargs to a method that takes…
Asone Tuhid
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4
votes
2 answers
Does prolog have a spread/splat/*args operator?
In many procedural languages (such as python), I can "unpack" a list and use it as arguments for a function. For example...
def print_sum(a, b, c):
sum = a + b + c
print("The sum is %d" % sum)
print_sum(*[5, 2, 1])
This code will print: "The…
byxor
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4
votes
1 answer
Powershell splat destroy variable
The argument to Split-Path below is incorrect and it should have been $delZipExe.
This makes the $delZipCmd hash be set to nothing.
I would expect WorkingDirectory value to be set to nothing in the $delZipCmd hash.
Why does this…
opedroso
- 103
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4
votes
1 answer
How to use a splat as a ruby method parameter
I'm looking at a ruby method
def test(*)
puts "hello"
end
I'm confused about the *. Obviously if I run test it returns "hello". But what if I pass an argument into test...
test("this argument")
How do I call that method within the test method…
thank_you
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4
votes
2 answers
Double splat on `nil`
My understanding is that a single splat on a non-array object calls to_a and then dissociates the elements apart. And since nil.to_a is defined to be [], the following conversion happens:
[:foo, *nil, :bar]
# => [:foo, *nil.to_a, :bar]
# => [:foo,…
sawa
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