# Assigning values: := => = assign sto Store

### 4.4.2 Assigning values: := => = assign sto Store

You can assign a value to a variable with the := operator. For example, to give the variable a the value of 4, you can enter

a:= 4

Alternatively, you can use the => operator; when you use this operator, the value comes before the variable;

4 => a

The function sto (or Store) can also be used; again, the value comes before the variable (the value is stored into the variable);

sto(4,a)

After any one of these commands, whenever you use the variable a in an expression, it will be replaced by 4.

You can use sequences or lists to make multiple assignments at the same time. For example,

(a,b,c):= (1,2,3)

will assign a the value 1, b the value 2 and c the value 3. Note that this can be used to switch the values of two variables; with a and b as above, the command

(a,b):= (b,a)

will set a equal to b’s original value, namely 2, and will set b equal to a’s original value, namely 1.

Another way to assign values to variables, useful in Maple mode, is with the assign command. If you enter

assign(a,3)

or

assign(a = 3)

then a will have the value 3. You can assign multiple values at once; if you enter

assign([a = 1, b = 2])

then a will have the value 1 and b will have the value 2. This command can be useful in Maple mode, where solutions of equations are returned as equations. For example, if you enter (in Maple mode)

sol:= solve([x + y = 1, y = 2],[x,y])

(see Section 5.55.6) you will get

[x=−1,y=2]

If you then enter

assign(sol)

the variable x will have value -1 and y will have the value 2. This same effect can be achieved in standard Xcas mode, where

sol:= solve([x + y = 1, y = 2],[x,y])

will return

⎡ ⎣ | ⎡ ⎣ | −1,2 | ⎤ ⎦ | ⎤ ⎦

In this case, the command

[x,y]:= sol[0]

will assign x the value -1 and y the value 2.