chapter five examples | Python Fiddle

#basic loop
"""
n = 5
while n > 0:
    print n
    n = n - 1
print "Blastoff!!!"

#infinite loop w/ break

n = 5
while n > 0:
    print "Infinite"
    print "loop"
    break
    
#zero trip loop

n = 0
while n >0:
    print "blah"
print "zero trip loop"

#breaking out of a oop
while True:
    line = raw_input("> ")
    if line == "done":
        break
    print line
print "Done"

#finishing an iteration with continue
# continue moves computer back up to the top of loop for next iterations
while True:
    line = raw_input('>')
    if line[0] == '#':
        continue
    if line == "done":
        break
    print line
print "Done"
#While loops are called "indefinte loops" because they keep running until a 
#logical condition becaomes False

#definite loops = runs loop once for each of the items in a set
# uses "for" and are called definite loop because they execute an exact 
# number of times

for i in [5, 4, 3, 2, 1]:
    print i
print 'Blastoff!!'

friends = ['Joseph', 'Glenn', 'Sally']

for friend in friends:
    print "Happy New Year: ", friend
print "Done"

loop idioms
loops have a high level view of what we want them to do

print 'before'
for thing in [9, 41, 12, 3, 74, 15]:
    print thing
print 'After'

largest_so_far = -1
print 'Before', largest_so_far
for the_number in [9, 41, 12, 3, 74, 15]:
    if the_number > largest_so_far:
        largest_so_far = the_number
    print largest_so_far, the_number
print 'After', largest_so_far

zork = 0
print "Before ", zork
for thing in [9, 41, 12, 3, 74, 15]:
    zork = zork + 1
    print zork, thing
print "After, ", zork

#summing in a loop
n = 0
print 'Before ', n 
for item in [9, 41, 12, 3, 74, 15]:
    n = n + item
    print n, "increment value ", item
print 'After ', n

count = 0.0
sum = 0.0
print 'before ', count, sum
for value in [9, 41, 12, 3, 74, 15]:
    count = count + 1
    sum = sum + value
    print count, sum, value
print 'After ', count, sum, sum / count

#filtering a loop
print 'Before'
for value in [9, 41, 12, 3, 74, 15]:
    if value > 20:
        print 'Large number', value
print 'After'

#search using a boolean variable
found = False
print 'Before ', found
for value in [9, 41, 12, 3, 74, 15]:
    if value == 3:
        found = True
    	break
    print found, value
print 'After ', found

smallest = None
print "Before"
for value in [9, 41, 12, 3, 74, 15]:
    if smallest is None:
        smallest = value
    elif value < smallest:
        smallest = value
    print smallest, value
print "After ", smallest
"""

largest = None
smallest = None
while True:
    num = raw_input("Enter a Number: ")
    if num == "done": 
        print "Done"
        break
    else:
        try:
            int(num) == True
        except:
            print "Invalid input"
            continue
    print num
    for the_number in num:
    	if largest is None:
            largest = the_number
        elif the_number > largest:
            largest = the_number
    for the_number in num:
        if smallest is None:
            smallest = the_number
        elif the_number < smallest:
            smallest = the_number
    
print "Maximum", largest
print "Minimum", smallest

Python Fiddle

Python Cloud IDE