Quadratic equation

[Daniel Sidorowicz]

Hello I need some hello I need some help with a programingproject, I'm
fairly new to programming so I do find it slightly confusing.

Here is my code for my main function which
passes my variable from a text file,
however when i run it I get the error code:

import math
import quadroot

def main():
        print "\n--------------------------------------------\n"
        print "Daniel Sidorowicz \n", "325 \n", "MCS 260, Spring 2009 \n",
"mp1id325"
        print "For instructions open file named README"
        print "Enter control-C to quit"
        infile = open("abc.txt",'r')
        L = infile.readlines()
        S = L.split()
        print S
        infile.close()
        outfile = open("output.txt",'a')
        eq = "ax^2.0 + bx + c = 0\n"

        for line in L:

                coef= a,b,c = (float(S[0]),float(S[1]),float(S[2]))
                print coef
                print "\n--------------------------------------\n"
                d = b**2.0 - 4.0*a*c

                if a != 0:
                    if d == 0.0 :
                     outfile.write(eq)
                     outfile.write(str(quadroot.root1(a,b,c,d)))
                    elif d > 0.0 :
                     outfile.write(eq)
                     outfile.write(str(quadroot.root2(a,b,c,d)))
                    elif d < 0.0 :
                     outfile.write(eq)
                     outfile.write(str(quadroot.root3(a,b,c,d)))
                    else :
                      "Never get here!"
                elif a ==  0 :
                   if b != 0:
                     outfile.write(eq)
                     outfile.write(str(quadroot.root5(b,c)))
                   else:
                      if c == 0:
                       outfile.write(eq)
                       outfile.write(str(quadroot.root6()))
                      else:
                         outfile.write(eq)
                         outfile.write(str(quadroot.root4(a,b,c,d)))
                else:
                  "Never get here!"

        outfile.close()

main()

AttributeError: 'list' object has no attribute 'split'

Can someone please explain/clarify this issue to me thanks!
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