HomePython Page 9 - Python 101 (part 2): If Wishes Were Pythons
Time For Lunch - Python
Begin your tour of Python with a look at its number and stringtypes, together with examples of how they can be used in simple Pythonprograms. Along the way, you'll also learn how to build conditionalexpressions, slice and dice strings, and accept user input from the commandline
Python also allows you to combine multiple conditional tests with the "and", "or" and "not" logical operators. If you consider the following code snippet,
if weekday == "Thursday":
if time == "12":
if place == "Italy":
lunch = "pasta"
you'll agree that is both complex and frightening. And so, in
addition to the comparison operators we've used so liberally thus far, Python also provides the "and", "or" and "not" logical operators which allow you to group conditional expressions together. The following table should make this clearer.
Assume delta = 12, gamma = 12 and omega = 9
delta == gamma and delta > omega
True
delta == gamma and delta < omega
False
delta == gamma or delta < omega
True
delta > gamma or delta < omega
False
not delta
False
Given this knowledge, it's a simple matter to rewrite
the example above in terms of logical operators:
if weekday == "Thursday" and time == "12" and place == "Italy":
lunch = "pasta"
Simple and elegant, wot?
And that's about it for the
moment. You've learned a lot today - you now know how to manipulate strings and numbers, obtain user input from the command line, and use the "if" family of conditional statements to control the flow of your program.
In the next article, I'll be discussing some of Python's loops, together with a close look at another very useful and interesting Python data structure - the list. You make sure that you come on back for that one!
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