3.4 Making Lists of Objects
In doing calculations, it is often convenient to collect together several objects, and treat them as a single entity. Lists give you a way to make collections of objects in Mathematica TE. As you will see later, lists are very important and general structures in Mathematica TE.
A list such as {3, 5, 1} is a collection of three objects. But in many ways, you can treat the whole list as a single object. You can, for example, do arithmetic on the whole list at once, or assign the whole list to be the value of a variable.
Here is a list of three numbers.
In[1]:= {3, 5, 1}
Out[1]= 
This squares each number in the list, and adds 1 to it.
In[2]:= {3, 5, 1}^2 + 1
Out[2]= 
This takes differences between corresponding elements in the two lists. The lists must be the same length.
In[3]:= {6, 7, 8} - {3.5, 4, 2.5}
Out[3]= 
The value of % is the whole list.
In[4]:= %
Out[4]= 
You can apply any of the mathematical functions in Section 2.3 to whole lists.
In[5]:= N[Sqrt[ % ]]
Out[5]= 
Just as you can set variables to be numbers, so also you can set them to be lists.
This assigns v to be a list.
In[6]:= v = {2, 4, 3.1}
Out[6]= 
Wherever v appears, it is replaced by the list.
In[7]:= v / (v - 1)
Out[7]= 
