#In this example we will look at some loops, the differences and their use
#We will only be looking at two loops in this example but they're many more
#the two loops in which we'll be looking at are FOR and WHILE LOOPS

#1. FOR LOOP
#The first loop we are going to look at is the for loop, this is one of the most common used loops
#A for loop in python is really a foreach loop, they are all one in python under for loop
#A for loop can be used when checking something e.g. 1 is less than 2
#there's many different uses for loops in python, we shall look at some of the ocmmon ones

#let us look at an example below:
for i in range(1, 5):
	print i
#the above will loop through all values between one and 5 and then print them all out
#NOTE that it prints 1 but does not print out 5, the last vaue is the number you wish to go up to
#the value i equals the current item we are looping i.e. i will first equal 1
#The range defines that we wish to search a range of numbers in the range 1 to 5

#Let us look at another example of a for loop, this time we shall loop through each item in a list
#we first set up a list called mylist and give it some values, these can be both integer or a string

mylist = [1,2,3,4,5,"hello","world"]
#we will now loop through each item in mylist printing out each element within it
for i in mylist:
    print i
#that is all, we tell i to equal the current item within the list and then go through each item
#we then print out each item.  We use i because it is easy to write :-)
#also notice that we mix both integers and strings within the list as this is allowed



#2. WHILE LOOP

#ok it is time to look at a different type of loop, this time the while loop.
#this loop is very effective if used correctly but has many side effects if used wrongly
#one of these side effects being tieing up the whole CPU which stops you doing anything within a program

#the while loop is used while something is happening e.g. while 1 is less than 5 do something
#the following example shows an example of a while loop in operation

count = 0 #we first create a variable called count
while (count < 9): #we say while count is less than 9 we wish to do something
   print 'The count is:', count # we then print out the words "the count is:" followed by count value
   count = count + 1 #next we increment the value of count by one and we go around the loop again

#NOTE:- I always try and stay away from while loops unless i need to use them, for loops are better
#For loop are also easier on the CPU but sometimes you do need to use a while loop as the following shows:
#while something:
   #do something

#the above experession is perfectly correct syntax in python, it means an expression like that would be allowed
#the above while loop style can be used when reading lines from a text file etc.
#a final advanced while loop statement is shown below

#we create a variable called var and tell it to equal to one
var = 1
while var == 1 :  # This constructs an infinite loop, while it is equal to 1 we want the following to happen 
   num = raw_input("Enter a number  :") #num variable equals the raw_input, this is data in which user enters
    #the raw input will say "enter a number :" and the user will type in a number which is then printed
   print "You entered: ", num
    #we tel var to equal 2 to get out of the loop
   var = 2
#good bye is then printed here, notice though the while loop keeps looping until user types something in and hits enter
print "Good bye!"

#THAT IS ALL, YOU NOW KNOW HOW TO USE LOOPS IN PYTHON
#YOU CAN LOOK UP OTHER TYPES OF LOOP TOO WUCH AS 'DO' AND 'DO WHILE' LOOPS BUT THEY ARE NOT COMMONLY USED DEPENDING ON YOUR PURPOSE