A data type is basically, the kind of value ( data) a variable can hold or store. Think of data types as the kind of data we use in our program. More technically, a data type dictates the size of memory allocated for a value.
For numbers, we have
integer also know as
int. We have
float which is also known as a
float. Floats are real numbers. For text, we have
string also known as
str. A string is a collection of at least zero characters, enclosed ( delimited) in single or double quote.
Eg of int: -3, -5, 2, 58, ... Eg of float: 1.0, 2.5, -3.000232, ... Eg of str: "", "John", 'Github', 'Python', "swift Python", '3', '-3.464', '+32-1', ...
''denote an empty string.
- '2' is not the same as 2. Why? This is because
'2'is a string because it is enclosed in a quote.
- A string is a text of any characters or just a sentence.
- If we want an output such as,
this is John's car, then what we have to do is to use double quote.
Eg: "This is John's car"or we have to escape it.
Eg: 'This is John\'s car'. We encourage the former.
int when the value of interest is an integer, a discrete data, such as age, number of people, number of babies, etc. For a value that can be counted, use
my_age = 45 number_of_babies = 3
float when the value of interest is a real, a continues value ( a real) such as the weight, height, time, speed, etc. For a value that can be measured, use
my_weight = 125.5 pi = 3.14
Python has a way of hinting the type of data passed into a variable. This is done by annotating the variable. It follows this format,
var_name:type=value . Note that this is not necessarily something we really should do - not compulsory. It will help catch some error though. We the developers ( the team) should decide whether we would like to use it or not. Hardly do I use it.
age:int = 34 name:str = "Veldora" weight:float = 120.50
Consider these whenever we want to create a variable.
- The variable must begin with a letter,
[a - z, A - Z]or an underscore
- Followed by any other character(s) such as a letter
[a - z, A - Z], numbers
[0 -9]or an underscore
- These must exclude any other character since these characters may have special meanings in python.
- Variable names are case sensitive, therefore,
Nameor any generic of
nameare not the same.
- A variable name must not be a reserved key words.
- PEP-8 has more on naming.
Exercise 1 ( creating a variable), and for the 10 variables we created earlier, state their data types
What will be the data type of the following values,
'University of github', 'swift-Python', 100, 12.0, 12, 'B+', '1 + 1', 345.0, 360, 3.1432, "sipping ice cream from a linux cup"
Now create a variable with a suitable name ( the name of the variable should be in a way that describes or gives information about what the value of interest is)
Eg: user_ip = '184.108.40.206' and full_name = 'John Doe'
- Data type refers to the kind of values we make use of in our program
- The Basic data types we have are the integer (int), float (float) and string (str) but there are also boolean values.
- A string is made up of zero or more characters enclosed in a single and a double quote.
name = ''is an empty string.
- Use int for counting values and float for measuring or continuous values.
- Once in a while go through PEP-8