ruby - 计算 Ruby 数组中的 Fixnums

Question

我有一个带有任意数量参数的函数。我的函数如下所示:

sum(n, *rest)

我如何遍历数组 rest 以便检查参数是否为 Fixnum，如果是则求和，否则不执行任何操作？例如:

sum(5,1,2,k,D,3)
# => 6

Answer 1

做如下:

ary = rest.grep(Fixnum)
# return the summation of the array elements, if array is not empty
# 0, when array is empty or contains only one element as `0`.
ary.reduce(0,:+) 

看#reduce和 grep .

例子:

ary = [1,"2",{1 => 2 },8]
ary.grep(Fixnum).inject(0,:+) # => 9
ary = ["2",{1 => 2 },(1..2)]
ary.grep(Fixnum).inject(0,:+) # => 0

# counting the how many Fixnums are there
ary = [1,"2",{1 => 2 },8]
ary.grep(Fixnum).size # => 2