or - in

{3:-4, 1:2, 0:-3}

-4x^3 + 2x - 3

# for example s = "4:3,2:1,-3:0,10:3"
def convert_str_list(s):
    result = []
    xs = s.split(",")
    for x in xs:
        ys = x.split(":")
        result.append((int(ys[0]), int(ys[1])))
    return result

def read_data(fname):
    with open(fname) as f:
        data = f.read().splitlines()
    newdata = []
    for line in data:
        x = line.split()
        newdata.append((x[0], convert_str_list(x[1]), convert_str_list(x[2])))
    return newdata

read_data("poly.dat")

[('add', [(-4, 3), (2, 1), (-3, 0)], [(9, 4), (8, 3), (4, 2)]),
 ('mul', [(4, 3), (2, 1), (3, 2), (-3, 0)], [(9, 4), (8, 3), (4, 2)])]

def add(p1,p2):
    pass

def mul(p1,p2):
    pass

def convert_list_file_str(p):
    result = ""
    for t in p:
        result = result + str(t[0]) + ":" + str(t[1]) + ","
    return result[:-1]

convert_list_file_str([(-4, 3), (2, 1), (-3, 0)])

'-4:3,2:1,-3:0'

def convert_list_display_str(p): remove all terms with 0 coefficient sort p in descending order of exponent for t in p: exponent = 0 exponent = 1 first term should not have a + sign in front of it positive coeff vs negative coeff

Monday 11 m to 2pm Thursday 9 am to Noon or email me the time

multiply polynomials 

result = {}
#Nested for loop
for t1 in p1:
    for t2 in p2:
        multiply t1 and t2 to get a new term 
        append the new term to the result using if-else
convert result into a list and then return the list 

add polynomials 

result = {}
# sequence of two for-loops
for t1 in p1:
    append t1 to result using if-else

for t2 in p2:
    append t2 to result using if-else
convert result into a list and then return the list 

def main():
    data = read_data(sys.argv[1])
    for x in data:
        if x[0] == "add":
            ???
        else:
            ???