An assignment gives a value to a variable or changes the current
value of a variable. A simple assignment instruction is:
number = 4
In the preceding program, a simple assignment instruction is:
store_a=0. The left side of the assignment (before the equal sign) contains
the name of the variable to receive a value from the right side (after
the equal sign). The right side can be an actual value (such as
4)
or an expression. An expression is something that needs to be evaluated,
such as an arithmetic expression. The expression can contain numbers,
variables, or both.
number = 4 + 4
number = number + 4
In the first example, the value of number is 8.
If the second example directly followed the first in a program, the
value of number would become 12. More about
expressions is in section Using Expressions.