# Project1 : quadratic equation .
# peter.vlasschaert@gmail.com,22-08-2022
#.....................................................
# ref : a primer on scientic programming with python
#     : Hans Petter Langtangen (Fifth ed.)
#     : Springer
# ----------------------------------------------------
print("math presentation >")
print("...................")
bb='a*x^2+b*x+c'
# https://www.codegrepper.com/ , python
print
print(bb)
print("python presentation")
print("...................")
aa = "a*x**2+b*x+c"
a = input(" variable a = ")
b = input(" variable b = ")
c = input(" variable c = ")
print(aa[0])
# position of a
m1=aa.replace(aa[0],a)
print(m1)
# position of b
m2=aa.find("b")
print(m2)
m2a=m1.replace(m1[m2],b)
print(m2a)
m3=len(aa)
# position of c
# m3-1 ,start index from 0
m3a=m2a.replace(m2a[m3-1],c)
print(m3a)
# computation : eval(string)
quadratic = lambda x:eval(m3a)
print(quadratic(2))
# makelist x= 1,2,3,4
m4=[quadratic(1),quadratic(2),quadratic(3),quadratic(4)]
print(m4)

def f(x):
    m5=eval(m3a)
    return m5

# output single value
#...............................
print(f(1))

# output list of values ,see : m4
#.................................
x1=1
list=[f(x) for x in range(x1, len(m4)+1)]
print(list)
# str ( = string )
list1=[ str(f(x)) for x in range(x1, len(m4)+1)]
print(list1)
# convert list of strings to floats
#..................................
# https://www.delftstack.com/howto/python/convert-list-to-float-python/
int_lst = [] # empty list (float_lst)
for item in list1:
    int_lst.append(int(item))    
print(int_lst)
# rem : code change: "int" to "float"