检查部分值是内部阵列

Question

我有这样的阵列：

>> arr = [["a",1,"b"],["a",2,"b"],["b",3,"d"],["t",6,"a"]] 

我要检查，如果[“一”，1]存在于arr内部而忽略了arr项的第三值。

是否有更好的方法，然后在arr第一去除每个项目的第3个值：

>> new_arr = [["a",1],["a",2],["b",3],["t",6]] 

，然后做

>> new_arr.include? ["a",1] 
true 

喜欢的东西：

arr.include? ["a",1,/*/] #the 3rd value can be anything 

感谢。

Answer 1

你可以试试下面的：

arr = [["a",1,"b"],["a",2,"b"],["b",3,"d"],["t",6,"a"]] 
arr.any? { |v1, v2, *| [v1, v2] == ["a", 1] } 
# => true 
arr.any? { |v1, v2, *| [v1, v2] == ["a", 4] } 
# => false 

包装逻辑的方法中：

def check_subarray(ary, sub_ary) 
    ary.any? { |e1, e2, *| [e1, e2] == sub_ary } 
end 

arr = [["a",1,"b"],["a",2,"b"],["b",3,"d"],["t",6,"a"]] 
check_subarray(arr, ["a", 1]) # => true 

Answer 2

另一种方式：

def values_there?(arr, val) 
    arr.transpose[0,val.size].transpose.include? val 
end 

values_there?(arr, ["a", 2]) #=> true 
values_there?(arr, [3, "d"]) #=> false 

Answer 3

下面是一个更复杂的版本@奥雅纳的答案（它可以处理任意长度）

def match_head(*head) 
    ->(full_array) { 
    head.each_with_index do |head_elem, idx| 
     return false if full_array[idx] != head_elem 
    end 

    true 
    } 
end 

ary = [["a",1,"b"],["a",2,"b"],["b",3,"d"],["t",6,"a"]] 
ary.any?(&match_head('a')) # => true 
ary.any?(&match_head('c')) # => false 
ary.any?(&match_head('a', 1)) # => true 
ary.any?(&match_head('a', 1, 'b')) # => true 
ary.any?(&match_head('a', 1, 'f')) # => false