Python – Loops and IterationLecture03

SumsWhat’s the sums of the numbers from 1 to 10?

sum = 0sum = sum + 1sum = sum + 2sum = sum + 3sum = sum + 4sum = sum + 5sum = sum + 6sum = sum + 7sum = sum + 8sum = sum + 9sum = sum + 10 print sum

SumsWhat’s the sums of the numbers from 1 to 1000?

sum = 0 for i in range(1001):   sum += i print sum

range()The range function generates an array up to its argument.

range(start)range(start, stop)range(start, stop, increment)

Operator - in

array = range(6) if 5 in array:   print "YEP!" for item in array:   print "YUP!"

For LoopsWhen you know how many times you want to loop

for x in range(1,10):   pass

While LoopsFor when you’re not sure how many times you want to iterate.

while (condition):   pass

Keywords for Iteration

breakcontinuepass

Break

sum = 0 for i in range(11):   sum += 1   if i == 5:      break   print sum

Continue

sum = 0 for i in range(11):   sum += 1   if i == 5:      continue   print sum

Pass

sum = 0 for i in range(11):   sum += 1   if i == 5:      pass   print sum

Nesting LoopsLoops can contain loops:

sum = 0 for i in range(10):   for j in range(10):      sum += 1 print sum

Printing a SquareIt can be accomplished the long way…

print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"print "* * * * * * * * * *"

Square – Deluxe Edition

for row in range(10):   for column in range(10):      print "*",   print ""