Tag Archives: lessons

Learning Python – Lesson 5: More on Numbers and Math

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Python Programming

It’s time to dig deeper into our work with numbers (including math) and strings.

What is Your Type?

First of all, it might be handy (especially as you learning), to have Python report the type of a variable or a literal value. For example:

C:\Users\terry>py
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> type(199.9)
<class 'float'>
>>> type("Howdy!")
<class 'str'>
>>> type(10043)
<class 'int'>
>>> a = "This is cool!"
>>> type(a)
<class 'str'>
>>>

More on Division

Division in Python comes in two variations:

/ carries out floating point division

// caries out integer (truncating) division

For example:

>>> 15 / 4
3.75
>>> 15 // 4
3

Math Precedence

Many of the math precedence rules would make sense to us (those that took some math in school!) For example, multiplication wins over addition. But fortunately, Python supports the use of ( ) to indicate precedence. This keeps us from having to worry about default behaviors. Here is an example:

Continue reading Learning Python – Lesson 5: More on Numbers and Math →

Learning Python – Lesson 3: Introducing Variables

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Free Python Training

We all know that variables are a key part of programming and scripting languages, and sure enough, they are a big part of Python. Here is how simple they are to implement:

#Today we are going to create and use some variables! 
#This is really cool! 
#Hey just to remind you, these are comments that are here to make our code "self-documenting"! 
#Python itself is ignoring the s#$t out of these! 
my_books = 14
my_years_on_planet = 47
books_per_year_on_planet = my_books / my_years_on_planet
print ("Below is my books per year on the planet!")
print (books_per_year_on_planet)

Notice here I am using Python 3 so I need parenthesis around the objects and text that I want to print instead of the older quotation marks! This is the most noticeable difference between Python version 2 and version 3. The PRINT function got a nice little update in this regard.

Here is the result of my program!

Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> 
======================= RESTART: C:\Users\terry\ex3.ps =======================
Below is my books per year on the planet!
0.2978723404255319

>>>
If you are you are using Python 2, you need the “older” syntax to make those print functions work right. Here is that version of our code for you:

#Today we are going to create and use some variables! 
#This is really cool! 
#Hey just to remind you, these are comments that are here to make our code "self-documenting"! 
#Python itself is ignoring the s#$t out of these! 
my_books = 14.0
my_years_on_planet = 47.0
books_per_year_on_planet = my_books / my_years_on_planet 
print "Below is my books per year on the planet!" 
print books_per_year_on_planet

Notice another change here – I need to indicate my variables are of the Float type in order to display my result in the format I need. So I enter my 14.0 and 47.0 for the variable values. I will discuss this in greater detail in the next post!

One final note, if you wanted to use the print function so that it would work in both version 2 and version 3, you would want to use both the ( and the ” as I did in the first program above. For example, I am using Python 2 now:

print ("Hello World!")

This returns:

Hello World!

just as it would in Python 3.

Remember, free Python training is waiting for you at CBT Nuggets!