PYTHON DICTIONARY

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Comments

Data types

Variables

If Else

If Elif Else

Functions

For loop

While loop

Data structures

String slicing

User defined function

Local/Global variable

Validation and Try

Methods

​File I/O

Pseudocode

Modules​

What is an If Else statement?

If-Else allows your code to split in response to what the user chooses to do. For example,  you can use If-Else to code a simple yes or no question and based on the user choice, either the Yes code will be followed or the No code will be followed.

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Python challenge - If statement

​Enter the following code in a Python code editor. Before running the code, what do you think it will do?. Press "F5" then "Enter" to run

Explanation:
The first line declares a variable called SkyColour that holds the value blue

The third line creates a condition based on SkyColour being blue. If it is true that the SkyColour is blue, then the line "The sky is blue today" will be displayed on the screen (line 4)

Line 6 will display "Good bye!" on the screen

If Statement explained

It is important to make the distinction in  Python between one equals sign and two equals sign:

= sets a value to a variable
== is a relational operator that means "is equal to". Other examples include:

Relational operator	Description
==	If the values of two operands are equal, then the condition becomes true.
!=	If values of two operands are not equal, then condition becomes true.
>	If the value of left operand is greater than the value of right operand, then condition becomes true.
<	If the value of left operand is less than the value of right operand, then condition becomes true.
>=	If the value of left operand is greater than or equal to the value of right operand, then condition becomes true.
<=	If the value of left operand is less than or equal to the value of right operand, then condition becomes true.

In this program, we have only coded for when a condition is met i.e. A message is displayed when the age is 18 or above, but we have not coded for if the condition is not met. We can do this by introducing the "Else" statement.

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Python challenge - If-Else and the input function

In this example, a user is prompted to enter either a "y" or a "n". Based on the users choice, a condition is met, the code branches and one of the messages is displayed.

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Python challenge - Greater than or equal to

Look at the code below. What will happen? What changes can you make to the code display the message "you are old enough to vote!"?

Python challenge - If-Else

In this example, we have coded for both a condition being met or not being met.​
Enter the following code in a Python code editor. Note that we have set the food as a kebab.  Press "F5" then "Enter" to run

What happens if you change the food to "chips" in both the variable called food and in the IF statement?