A data type consisting of numbers letters and symbols in PYTHON
The five main data types you will need to understand and use are: Show
Integer - Is a whole number which can be either positive (0 or above) or negative (under 0). Lets look at how this can be used in pseudocode and Python. Real - Is any number (positive or negative) including decimal places. In Python areal number is called a floating-point number or float for short. Character - Is a single symbol such as a letter. Take the word “hello” this could be defined as 5 single characters “h”, ”e”, “l”, “l”, and “o”. String - Is a series of characters that are combined to make a single piece of data. They are defined by adding speech marks around the value. However, in Python anything that the user inputs is treated as a string text unless otherwise specified.
Boolean - Boolean values can have one of two values, usually True or False and cannot be left empty. Casting - Casting is when you convert a variable value from one type to another. This is, in Python, done with functions such as int() or float() or str(). IntroductionIn Python, like in all programming languages, data types are used to classify one particular type of data. This is important because the specific data type you use will determine what values you can assign to it and what you can do to it (including what operations you can perform on it). In this tutorial, we will go over the important data types native to Python. This is not an exhaustive investigation of data types, but will help you become familiar with what options you have available to you in Python. PrerequisitesYou should have Python 3 installed and a programming environment set up on your computer or server. If you don’t have a programming environment set up, you can refer to the installation and setup guides for a local programming environment or for a programming environment on your server appropriate for your operating system (Ubuntu, CentOS, Debian, etc.) BackgroundOne way to think about data types is to consider the different types of data that we use in the real world. An example of data in the real world are numbers: we may use whole numbers (0, 1, 2, …), integers (…, -1, 0, 1, …), and irrational numbers (π), for example. Usually, in math, we can combine numbers from different types, and get some kind of an answer. We may want to add 5 to π, for example:
We can either keep the equation as the answer to account for the irrational number, or round π to a number with a brief number of decimal places, and then add the numbers together:
But, if we start to try to evaluate numbers with another data type, such as words, things start to make less sense. How would we solve for the following equation?
For computers, each data type can be thought of as being quite different, like words and numbers, so we will have to be careful about how we use them to assign values and how we manipulate them through operations. NumbersAny
number you enter in Python will be interpreted as a number; you are not required to declare what kind of data type you are entering. Python will consider any number written without decimals as an integer (as in IntegersLike in
math, integers in computer programming are whole numbers that can be positive, negative, or 0 (…, Info:
To follow along with the example code in this tutorial, open a Python interactive shell on your local system by running the We can print out an integer like this:
Or, we can declare a variable, which in this case is essentially a symbol of the number we are using or manipulating, like so:
We can do math with integers in Python, too:
Integers can be used in many ways within Python programs, and as you continue to learn more about the language you will have a lot of opportunities to work with integers and understand more about this data type. Floating-Point NumbersA floating-point number or a float is a real number, meaning that it can be either a rational or an irrational number. Because of this, floating-point numbers can
be numbers that can contain a fractional part, such as Like we did with the integer, we can print out a floating-point number like this:
We can also declare a variable that stands in for a float, like so:
And, just like with integers, we can do math with floats in Python, too:
With
integers and floating-point numbers, it is important to keep in mind that 3 ≠ 3.0, as BooleansThe Boolean data type can be one of two values, either True or False. Booleans are used to represent the truth values that are associated with the logic branch of mathematics, which informs algorithms in computer science. Whenever you see the data type Boolean, it will start with a capitalized B because it is named for the mathematician George Boole. The values Many operations in math give us answers that evaluate to either True or False:
Like with numbers, we can store a Boolean value in a variable:
We can then print the Boolean value with a call to the
Since 5 is not greater than 8, we will receive the following output:
As you write more programs in Python, you will become more familiar with how Booleans work and how different functions and operations evaluating to either True or False can change the course of the program. StringsA string is a sequence of one or more characters (letters, numbers, symbols) that can be either a constant or a variable. Strings exist within either single quotes
You can choose to use either single quotes or double quotes, but whichever you decide on you should be consistent within a program. The basic program “Hello, World!” demonstrates how a string can be used in computer programming, as the characters that make up the phrase
As with other data types, we can store strings in variables:
And print out the string by calling the variable:
Like numbers, there are many operations that we can perform on strings within our programs in order to manipulate them to achieve the results we are seeking. Strings are important for communicating information to the user, and for the user to communicate information back to the program. ListsA
list is a mutable, or changeable, ordered sequence of elements. Each element or value that is inside of a list is called an item. Just as strings are defined as characters between quotes, lists are defined by having values between square brackets A list of integers looks like this:
A list of floats looks like this:
A list of strings:
If we define our string list as
We can print them out by calling the variable:
And the output looks exactly like the list that we created:
Lists are a very flexible data type because they are mutable in that they can have values added, removed, and changed. There is a data type that is similar to lists but that can’t be changed, and that is called a tuple. TuplesA tuple is used for grouping data. It is an immutable, or unchangeable, ordered sequence of elements. Tuples are very similar to lists, but they use parentheses A tuple looks like this:
We can store a tuple in a variable and print it out:
Like in the other data types, Python prints out the tuple just as we had typed it, with parentheses containing a sequence of values. DictionariesThe dictionary is Python’s built-in mapping type. This means that dictionaries map keys to values and these key-value pairs
are a useful way to store data in Python. A dictionary is constructed with curly braces on either side Typically used to hold data that are related, such as the information contained in an ID, a dictionary looks like this:
You will notice that in addition to the curly braces, there are also colons throughout the dictionary. The words to the left of the colons are the keys. Keys can be made up of any immutable data type. The keys in the dictionary above are:
The words to the right of the colons are the values. Values can be comprised of any data type. The values in the dictionary above are: Like the other data types, let’s store the dictionary inside a variable, and print it out:
If we want to isolate Sammy’s color, we can do so by calling
As dictionaries offer key-value pairs for storing data, they can be important elements in your Python program. ConclusionAt this point, you should have a better understanding of some of the major data types that are available for you to use in Python. Each of these data types will become important as you develop programming projects in the Python language. You can learn about each of the data types above in more detail by reading the following specific tutorials:
Once you have a solid grasp of data types available to you in Python, you can learn how to convert data types. What is the data type for symbols in Python?Strings. A string is a sequence of characters enclosed in single quotes double quotes or triple quotes. The character present in a string can be any digit, letter, special symbols, or white spaces. String in python is an immutable data type that is once a value is assigned to the variable it cannot be changed later.
What type of data is numbers in Python?In Python, numeric data type represent the data which has numeric value. Numeric value can be integer, floating number or even complex numbers. These values are defined as int , float and complex class in Python.
What are the 3 data types in Python?Python Numbers. int (signed integers). float (floating point real values). complex (complex numbers). What is alphanumeric data type in Python?Python String isalnum() Method
The isalnum() method returns True if all the characters are alphanumeric, meaning alphabet letter (a-z) and numbers (0-9). Example of characters that are not alphanumeric: (space)!
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