Date post: | 09-Jul-2015 |
Category: |
Education |
Upload: | aswin-krishnamoorthy |
View: | 68 times |
Download: | 0 times |
AGENDA
Decision Making
Loops
Python Decision Making
Decision making structures require that the programmer specify one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.
Types of decision making statements
IF statements
IF...ELSE statements
Nested IF statements
IF statements Flow Diagram:
Test Exp
Body of if
TRUE FALSE
EXIT
IF...ELSE statements Flow Diagram:
Test Exp
Body of Else
FALSE
EXIT
If Block TRUE
The else statement is an optional statement and there could be at most only one else statement following if .
LOOPS
A loop statement allows us to execute a statement or group of statements multiple times
Python programming language provides following types of loops to handle looping requirements
While loop
For loop
While Loop
Example:
count = 0
while (count < 9):
print 'The count is:', count
count = count + 1
print "Good bye!"
For Loop
If a sequence contains an expression list, it is evaluated first. Then, the first item in the sequence is assigned to the iterating variable iterating_var. Next, the statements block is executed. Each item in the list is assigned to iterating_var, and the statement(s) block is executed until the entire sequence is exhausted.
Example:
for letter in 'Python':
print 'Current Letter :', letter
String
Loop Control Statements:
Loop control statements change execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed.
break statement continue statement pass statement
Break Statement:
Example
for letter in 'Python':
if letter == 'h':
break
print 'Current Letter :', letter
Break Statement
continue statement
The continue statement in Python returns the control to the beginning of the while loop. The continue statement rejects all the remaining statements in the current iteration of the loop and moves the control back to the top of the loop.
for letter in 'Python':
if letter == 'h':
continue
print 'Current Letter :', letter
continue statement
pass statement
The pass statement in Python is used when a statement is required syntactically but you do not want any command or code to execute.
The pass statement is a null operation; nothing happens when it executes.
for letter in 'Python':
if letter == 'h':
pass
print 'This is pass block'
print 'Current Letter :', letter
Reference
http://www.tutorialspoint.com/python/