# variables and lists
# pmb 10/2/02

# variable are sort-of like the cells in a spreadsheet
# they can hold numbers or character strings
x=5
iamavariable='hi mom'
print x,iamavariable

# all variables have names; variables with different caps
# are different variables
IamAVariable='hi dad'
print iamavariable, IamAVariable

# you can do math on variables if they both have numbers in them
zxy = 32
print "zxy is now ", zxy,
zxy = zxy + 10
print " and now its ",zxy

# lists- you can make lists of variables if it's a handy way to access them
years = [ 1980, 1982, 1984, 1986, 1977 ]
print " list of years is ", years
# lists are accessed thusly- this gets the 4th year in the list
print "4th year is ",years[4]

# for loops let you cycle through entries in a list easily
for zxy in years:
    print zxy

# you can cycle through consecutive numbers with a range list
for zxy in range( 2,10 ):
    print "for list with range ",zxy

# there are also lists of characters
presidents = [ 'carter','ford','reagan','bush','clinton']
print "there are ",len(presidents)," presidents, first is ",presidents[0]
for x in presidents:
    print 'hail to chief ', x

# sorting lists of chars is easy
presidents.sort()
print "sorted presidents ", presidents

# can even have lists of chars and numbers
aMixedList = [ 1996, 'clinton',2002, 'churchill' ]
for x in aMixedList:
    print x

#variables can also be objects, like in vpython demos
#there are also hashes and tuples