Skip to main content

Conditional Statements


Conditional STATEMENTS

 Normally, the statements are executed sequentially as written in the program (i.e. Top to bottom). This is known as the normal flow of control. But sometimes the operational flow of control has to
be altered depending upon a condition. The statements that allow to do so, are known as selection statements. Most important selection statement that python offers is the If statement.
Selection statements are also known as conditional statements or decision statements.

THE IF STATEMENT

 An if statement tests a particular condition; if the condition evaluates to true, a course of action is followed i.e. a statement of a set of statements is executed. If the condition is false the course of action is ignored.
The syntax of if statement is as shown below:
if (expression) :
Statement

THE ELIF STATEMENT

 In some cases the program requires you to write multiple if statements. This results in many condition evaluations thus slowing up the program. So to avoid this elif statements can be used.
Unlike if statement elif statements stops further evaluation of conditional statement once a condition is true. The keyword ‘elif‘ is short for ‘else if’, and is useful to avoid excessive indentation.
An if ... elif ... elif ... sequence is a substitute for
the switch or case statements found in other languages.
USING ELSE
If all the conditions inside conditional statements are false then
the body of the else loop will be executed.
If (expression) :
Statement1
Elif(expression):
Statement2
Else:
Statement3
If , elif and else this way, together form the if-elif-else ladder
Labels:

Comments

Post a Comment

Popular posts from this blog

Writing first python program

  We are here to write our first program,it will  be an easy program just printing the entered word or value. The syntax of python language is very simple and easy and you dont have to confuse your mind with any complexity. So here is our first program print ( "Hello my name is abc" ) print command is used to display the output written in brackets with inverted commas. As we have typed the sentence "Hello my name is abc". So this command will simply print this sentence as show above in the picture.  
Post a Comment
Read more

Loop Statements

Loop STATEMENTS The Loop statements allow a set of instructions to be performed repeatedly until a certain condition is fulfilled. The iteration statements are also called loops or looping statements. THE FOR LOOP The for loop is the easiest to understand of the python loops. Syntax: For I in range(lowerlimit,upperlimit): Loop Body The program will run until I value becomes equal to upperlimit – 1. Example: For I in range(1,5): Print(“Hello”) This program will print Hello 4 times, ie from 1 to 4 (upper limit-1)  I value will start as 1 then loop body will get executed and I value will be incremented. This keeps on taking place until I ==upper limit-1 . After that the program comes out of loop body. THE WHILE LOOP The second loop available in python is the while loop. The while loop is an entry controlled loop. The syntax of a while loop is while (expression): Loop-body Where loop body keep on getting executed until the expression becomes false. When the expression becomes false, th...
Post a Comment
Read more