4525.sagews

def validIsbn(list,length):
    c=11
    for i in range(0,length):
        c=c-(length+1-i)*list[i]
        
    c1=mod(c,11)
    print 'One obtains c1=',c1, 'hence the ISBN code is: ',
    for j in range(0,length):
        if ((mod(j,3)==0)&(j!=0)):
            print '-',
        print list[j],
    print '-',c1

validIsbn([2,1,0,0,5,0,6,9,2],9)

One obtains c1= 7 hence the ISBN code is: 2 1 0 - 0 5 0 - 6 9 2 - 7

def eanCode(list):
    c=10;a=0;b=0
    for i in range(0,6):
        a=a+list[2*i]
    print a
    for i in range(1,7):
        b=b+list[2*i-1]
    print b
       
    c0=mod(10-(a+3*b),10)
    print 'The EAN-13 code is: ',
    for i in range(0,12):
        if ((i==1)|(i==7)):
            print '-',
        print list[i],
    print c0

eanCode([9,7,8,2,1,0,0,5,0,6,9,2])

27 22 The EAN-13 code is: 9 - 7 8 2 1 0 0 - 5 0 6 9 2 7