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 Need to use range with decimals
#1
Hello,

I need to write a program that asks for values from a user and then use the values in a formula. One thing I need to do is ask the user if they want a range, list, or single value for one of the parameters, but I can't figure out how to do this. I don't think I'm allowed to use numpy for this. Here is my code:

import math

h = float(input("What is the value of H0 (in km/s/Mpc)?"))
z = float(input("What is the value of the redshift?")
j = float(input("what is the value of the matter density parameter?"))
cs = input("Do you want a flat or open cosmology (1 = flat, 0 = open)?")
ran = input("Do you want a range of readshifts (min, max, increment), or a list (type range, list, o$

if ran == "range":
    i = float(input("What is the minimum of the range you desire (enter min z value)?"))
    k = float(input("What is the maximum of the range you desire (enter max z value)?"))
    u = float(input("By what increment do you want z to be calculated (enter increment size)?"))
    for z in range(i, k, u):
        z = z + u

There's more after that, but I don't want to post my entire code for this issue unless I have to.
So, the range gives me SOMETHING if I give it only integers, but it only gives me one value and I don't know why. For example, if I use (1, 3, 1), it only gives one value instead of 3. Beyond this, using integers only makes the range pointless as redshifts aren't often integers.If anyone knows a way this can be done, I greatly appreciate it. Thank you.
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#2
Quote:for one of the parameters,
which one?
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#3
If you want to build the list based on the user providing a min, max, and increment, you don't need to use range:

data = []
current = min_value
while current < max_value:
    data.append(current)
    current += increment
Craig "Ichabod" O'Brien - xenomind.com
I wish you happiness.
Recommended Tutorials: BBCode, functions, classes, text adventures

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#4
A range is a list, and a list can have a single value.
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#5
Ok,so now I have this:

if ran == "range":
    i = float(input("What is the minimum z value?"))
    k = float(input("What is the maximum z value?"))
    u = float(input("By what increment?"))
    data = []
    current = i
    while i < k:
        data.append(i)
        current += u

But after asking for the min, max and increment, nothing happens. I'm guessing I need something in the brackets after data, but I'm not sure what would go there.
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#6
Well, you haven't shown us the code after that section, so we have no way of knowing what should happen. What inputs are you using, and what is the value of data after the loop?
Craig "Ichabod" O'Brien - xenomind.com
I wish you happiness.
Recommended Tutorials: BBCode, functions, classes, text adventures

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#7
Here is the entire program:
import math

h = float(input("What is the value of H0 (in km/s/Mpc)?"))
j = float(input("what is the value of the matter density parameter?"))
cs = input("Do you want a flat or open cosmology (1 = flat, 0 = open)?")
ran = input("Do you want a range of readshifts (min, max, increment), or a list (type range, list, o$


if ran == "range":
    i = float(input("What is the minimum z value?"))
    k = float(input("What is the maximum z value?"))
    u = float(input("By what increment?"))
    z = i
    data = [z]
    while i < k:
        data.append(i)
        z += u

def eta(a, omega):
    s = ((1- omega)/omega)**(1/3)
    return 2*math.sqrt(s**3 + 1)*(1/(a**4) - 0.01540*s/(a**3) + 0.4304*(s**2)/(a**2)\
                                  + 0.19097*(s**3)/a +0.066942*s**4)**(-1/8)
c = 3e8
q = (j/2)

d1 = (1/(1 + z))*(c/h)*(eta(1, j) - eta(1/(1 +z), j))
d1 = d1*(math.pi/180)*(1/3600)

d2 = (c/(h*q**2))*(((z*q) +(q - 1)*(math.sqrt(2*z*q + 1) - 1))/((1 + z)**2))
d2 = d2*(math.pi/180)*(1/3600)

if cs == "1":
    print(d1)
else:
    print(d2)

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#8
You create the list data, and then you don't do anything with it. Nothing is going to happen with data if you don't use it.

And those single letter variable names make your code really hard to read. Please try to use more descriptive variable names.
Craig "Ichabod" O'Brien - xenomind.com
I wish you happiness.
Recommended Tutorials: BBCode, functions, classes, text adventures

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