And, Or, Not: Combining Conditions

Name: And, Or, Not: Combining Conditions
Author: StemPy Lab

One simple condition is often not enough. A person can enter a club if they are old enough and have a ticket. A shop gives a discount to students or to senior citizens. In this course you combine conditions with and, or and not, check a range, ask whether a value is inside a group with in, and put one decision inside another. You learn to prove a combined condition with a truth table, and to simplify a condition with the rule of not. A club entry program at the end uses everything. The practice tests your conditions on many cases and tells you which ones fail.

5 lessons, about 2 h 30 min5 simulations13 problems10 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (5 lessons)

Lesson 1about 35 min
and, or and not
and, or and not join conditions. A and B is True only when both are True. A or B is True when at least one is True. not A turns True into False and False into True. In a long condition, Python does not first, then and, then or, and brackets change the order. Write each comparison in full: age >= 18 and age <= 60 is right, and age >= 18 and <= 60 is a SyntaxError.
1 simulation2 practice questions4 Python programs6 problems2 Python labs1 question set
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Lesson 2about 30 min
Ranges and the word in
To check a range, write two comparisons joined by and, or use the short chain 50 <= marks <= 75. The word in asks whether a value is inside a group: a letter in a text, a word in a longer text, or a value in a list. not in is the opposite. A condition such as letter == 'a' or 'e' is a trap, because the text 'e' alone is always True, so each comparison must have its own left side. Use in to write such a test in one short line.
1 simulation2 practice questions3 Python programs4 problems2 Python labs
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Lesson 3about 30 min
A decision inside a decision
A decision can sit inside another decision. The inner if is asked only when the outer condition is True, and it needs one more level of indent. Nested decisions give different messages for different reasons, but they quickly become hard to read. The same logic can often be written flat with and and elif. Choose the form that is easier to read, test every branch, and avoid going deeper than two levels.
1 simulation2 practice questions2 Python programs2 problems1 Python lab
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Lesson 4about 30 min
Truth tables and the rule of not
A truth table lists every possible combination of True and False for the parts of a condition and the result for each. With two parts there are four rows, and with three there are eight. A truth table proves that two conditions are the same. The rule of not says that not (A and B) is the same as (not A) or (not B), and not (A or B) is the same as (not A) and (not B). Use it to simplify a condition. A leap year check is a good example, with the rule: divisible by 4, except for a century year that is not divisible by 400.
1 simulation2 practice questions3 Python programs1 problem1 Python lab
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Lesson 5about 25 min
Project: who can enter the club?
In this project we write the entry rules of a club. Under 18 is never allowed. At 18 or more, a person needs a ticket, but a member enters without a ticket. We write the rules in plain words, build a table of the cases, write the condition with and, or and not, test all the combinations, and then extend the club with a closing time and a guest rule. The project uses combined conditions, a flat decision with elif, and a test table with every branch.
1 simulation2 practice questions1 Python program1 Python lab1 note
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And, Or, Not: Predict the Output

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And, Or, Not: Combining Conditions

Course outline (5 lessons)

and, or and not

Ranges and the word in

A decision inside a decision

Truth tables and the rule of not

Project: who can enter the club?

Test Your Learning

Your teacher

Discussion (0)