if syntax python
Here is the next script of Python you will enter, which introduces you to the if- statement. Type this in, make it run exactly right, and then we’ll see if your practice has paid off.
1 people = 20 2 cats = 30 3 dogs = 15 4 5 6 if people < cats: 7 print "Too many cats! The world is doomed!" 8 9 if people > cats: 10 print "Not many cats! The world is saved!" 11 12 if people < dogs: 13 print "The world is drooled on!" 14 15 if people > dogs: 16 print "The world is dry!" 17 18 19 dogs += 5 20 21 if people >= dogs: 22 print "People are greater than or equal to dogs." 23 24 if people <= dogs: 25 print "People are less than or equal to dogs." 26 27 28 if people == dogs: 29 print "People are dogs."
Too many cats! The world is doomed! The world is dry! People are greater than or equal to dogs. People are less than or equal to dogs. People are dogs.
In Python, If Statement is used for decision making. It will run the body of code only when IF statement is true. When you want to justify one condition while the other condition is not true, then you use “if statement“.
- What do you think the if does to the code under it?
- Why does the code under the if need to be indented four spaces?
- What happens if it isn’t indented?
- Can you put other boolean expressions from Exercise 27 in the if- statement? Try it.
- 5. What happens if you change the initial variables for people, cats, and dogs?
What does += mean?
The code x += 1 is the same as doing x = x + 1 but involves less typing. You can call this the “increment by” operator. The same goes for – = and many other expressions you’ll learn later.