javascript Ruby 中的 indexOf

Question

提问by Hymanie Chan

Just wondering is there the same method for an Array object similar to indexOf in JavaScript?

只是想知道对于类似于 JavaScript 中的 indexOf 的 Array 对象是否有相同的方法？

For example:

例如：

arr = %w{'a', 'b', 'c'}
c = 'c'
if (arr.indexOf(c) != -1)
// do some stuff
else
// don't do some stuff

Answer 1

It is the .indexmethod of Array.

它是.indexArray的方法。

In ruby, only falseand nilare considered as false value, so you could just do:

在 ruby 中， onlyfalse和nil被认为是假值，所以你可以这样做：

arr = %w{a, b, c}
c = 'c'
if arr.index c
  # do something
else 
  # do something else
end

Answer 2

If you want to check the presence of an element in the array, you can use include?:

如果要检查数组中是否存在某个元素，可以使用include?：

if arr.include?(c)
  # do stuff
else 
  # don't
end

Answer 3

Use Array#index for this:

为此使用 Array#index：

c = 'c'
%w{a b c}.index(c)

Answer 4

if arr.last == c
  # do some stuff
else
  # don't do some stuff
end