Compare and Contrast int vs. float

Programming languages must distinguish between different types of data. Since we want to introduce simple Python computations, it makes sense to discuss numerical data. The goal of this section is to introduce two fundamental numerical data types: int and float. The int data type refers to integer data. Numbers not containing digits to the right of the decimal point such as - 10 , 0, and 357 are integers. The float data type refers to floating-point data. Numbers containing digits to the right of the decimal point such as 1.3, -3.14, and 300.345567 are floating-point numbers.

After you complete this section, you should be able to explain the difference between int and float. There are deeper reasons (beyond the scope of this course) why you might distinguish between these data types; those have to do with how they are represented within a computer system. Our goal for this section is simply to be able to visually identify integer and floating-point numbers. On this page, you will see more examples of int and float.

The int data type refers to integer numerical data. In the rightmost window of the Repl.it IDE, use your mouse to click to the right of the > command prompt. Next, type the integer 2 and press the "enter" key on your keyboard. You should see the IDE echo the value back to the screen. Try this a few times with other examples to be sure you understand the int data type.

The float data type refers to floating-point numerical data. In the rightmost window of the Repl.it IDE, use your mouse to click to the right of the > command prompt. Next, type the floating-point number 2.57 and press the "enter" key on your keyboard. You should see the IDE echo the value back to the screen. Try this a few times with other examples that have been provided to be sure you understand the float data type.

It is of the utmost importance that you understand the value 2 is of type int, while 2.0 is of type float. On paper, this might not seem like a big difference, but the decimal point is how a computer tells the difference between these two data types.

Arithmetic Operators

Operator Operation Expression English description Result
+ addition 11 + 56 11 plus 56 67
- subtraction 23 - 52 23 minus 52
* multiplication 4 * 5 4 multiplied by 5 20
** exponentiation 2 ** 5 2 to the power of 5 32
/ division 9 / 2 9 divided by 2 4.5
// integer division 9 // 2 9 divided by 2 4
% modulo (remainder) 9 % 2 9 mod 2 1

Types int and float

type is a set of values and operations that can be performed on those values.

Two of Python's numeric types:

  • int : integer

For example: 3, 4, 894, 0, -3, -18

  • float : floating-point number (an approximation of a real number)

For example: 5.6, 7.342, 53452.0, 0.0, -89.34, -9.5


Arithmetic Operator Precedence

When multiple operators are combined in a single expression, the operations are evaluated in order of precedence.

Operator Precedence
** highest
- (negation)
*, /, //, %
+ (addition), - (subtraction) lowest

Syntax and Semantics

Syntax: the rules that describe valid combinations of Python symbols.

Semantics: the meaning of a combination of Python symbols is the meaning of an instruction — what a particular combination of symbols does when you execute it.


Errors

A syntax error occurs when an instruction with invalid syntax is executed. For example:

>>>3)+2*4
SyntaxError: invalid syntax

A semantic error occurs when an instruction with invalid semantics is executed. For example:

>>> 89.4/0
Traceback(most recent call last):
    File"", line 1,in
    89.4/0
ZeroDivisionError:float division by zero

Source: MS, https://www.oercommons.org/authoring/5133-a-short-notes-on-python-programming/2/view#h2
Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License.

Last modified: Tuesday, February 22, 2022, 3:06 PM