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Numbers can be any of the digit characters between and including 0 and 9.
Click PEP 8 -- Style Guide for Python Code to learn more about how to create identifiers for variables and other programming elements as well.
The first thing that you need to do is to start the interactive programming environment. If you have forgotten how to do that, see the module titled Itse1359-1010-Getting Started .
The interactive fragment shown in Figure 1 :
| Figure 1 . Create and use some variables. |
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>>>x=6 # create and populate x>>>y=5 # create and populate y>>>x+y # add x to y and display the sum
11>>> |
Using the informal jargon from an earlier paragraph, two pigeonholes are established in memory and are given nicknames of x and y.
Integer values of 6 and 5 are stored in the two pigeonholes using the assignment operator (=).
The use of the assignment operator in this fashion causes the value of its right operand to be stored in the pigeonhole identified by its left operand .
If you don't recognize the use of the term operand, see the earlier module titled Itse1359-1020-Numbers for an explanation.
In this case, the right operands of the assignment operators are literal numeric values .
The left operands of the assignment operators are the nicknames identifying the two memory locations that constitute the variables named x and y.
The values are retrieved from eachpigeonhole and added together in the third line of code. The result of the addition (11) is displayed as output from the expression x+y .
Python allows you to assign the same value to several variables, causing them to come into existence (begin to occupy memory) at the same time if necessary
Consider the interactive fragment shown in Figure 2 .
| Figure 2 . Assigning the same value to several variables. |
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>>>a=b=c=10 # assign 10 to several variables>>>a+b+c # add them together
30>>>a=b=c=20 # assign 20 to same variables>>>a+b+c # add them together
60>>> |
The first line of code in Figure 2 creates three variables named a , b , and c , and assigns a value of 10 to each of them.
They are then added together, in the second line of code, to produce an output value of 30.
The fourth line of code assigns the value of 20 to the same three variables, replacing what was previously there with the new value. Againthey are added together, this time producing an output value of 60.
Pigeonhole explanations are good for starters, but let's move on to a more comprehensive and technically correct explanation.
According to the Python gurus, everything (or at least almost everything) in Python is an object. I indicated earlier that data values are stored in variables.In reality, that is not the case. Figure 3 shows the truth about pigeonholes, variables, and objects.
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