matlab - 如何在 matlab 中使用 if 和 or 语句比较数字？

Question

如果数组的元素b=[1,2,3,4,5]等于 1 或 2 或 5，我想返回 true。我该怎么做？

Answer 1

There are different ways to do that:

• Test an individual element against one number

  b(1) == 5

• Test an individual element against several numbers, i.e. is the first element either 1 or 2 or 5?

  b(1) == 1 || b(1) == 2 || b(1) == 5

  %# which is equivalent to

  any(b(1) == [1 2 5];

• Test all (or many) elements against one number

  b == 1; %# a vector with t/f for each element

• Test all elements against several numbers

  b == 1 | b == 2 | b == 5 %# note that I can't use the shortcut ||

  %# this is equivalent to

  ismember(b,[1 2 5])

Answer 2

这很简单。要测试数字的相等性，您只需使用==运算符。

if (b(1) == 5)
    %% first element of b is 5 
    %% now implement code you require

同样，您可以测试矩阵中任何元素的相等性。要测试多个值，请使用逻辑或运算符||，==例如

if (b(1) == 5 || b(1) == 2 || b(1) == 1)
    %% first element of b is 1,2 or 5 
    %% now implement code you require