How to use float variable with range function in python?

Question

Description: I have three variable a, x and y. I want to apply the following, if variable a in range(x, y) print the a variable

Code:

a = "0.50"
x = "-14.40"
y = "0.50"

for a in range(int(x), int(y)):
    print a

Error (of course):

ValueError: invalid literal for int() with base 10: '-14.40'

Pythonista i need your help here please!!

yes you're totally right @DanielRoseman but like you know range don't support float rather than int number — ME_sociaty, May 16 '18 at 08:38
`range` is not intended to be used in this way. Why don't you simply check `if a >= x and a <= y: # then do something`. — JenkinsY, May 16 '18 at 08:38
It's not clear to me what you actually want that code to do. Do you want it to print all the integers between -14.40 and 0.5 ? — PM 2Ring, May 16 '18 at 08:41
You may want this: https://stackoverflow.com/questions/7267226/range-for-floats/7267806 — JenkinsY, May 16 '18 at 08:41
It looks like you want to go from `x` to `y` in steps of 0.5. You can't use `range()` for that, it is for integers. Write a loop and do the addition yourself. — BoarGules, May 16 '18 at 08:42
@BoarGules Where do you get that "steps of 0.5"? I suspect that the OP doesn't actually want to do any looping at all... — PM 2Ring, May 16 '18 at 08:44
@PM2Ring It looked to me as if what he actually wanted to do was `for a in range(-14.4,0.5,0.5):`. But it appears his misunderstanding of `range()` was even more fundamental than I imagined. — BoarGules, May 16 '18 at 08:49

score 1 · Accepted Answer · answered May 16 '18 at 08:51

The Python 2 range function is irrelevant for this task. You just need to convert those strings to floats and do simple comparison tests. Eg,

a = "0.50"
x = "-14.40"
y = "0.50"

afloat = float(a)
if float(x) <= afloat and afloat <= float(y):
    print a

output

0.50

This can be written more simply (and more efficiently) using Python's comparison chaining.

a = "0.50"
x = "-14.40"
y = "0.50"

if float(x) <= float(a) <= float(y):
    print a

FWIW, in Python 3, the range object can be useful for testing membership of a range, but it wouldn't be useful for your case. Eg,

>>> r = range(1, 10, 2)
>>> list(r)
[1, 3, 5, 7, 9]
>>> 3 in r
True
>>> 4 in r
False
>>> 3.5 in r
False

score 1 · Answer 2 · answered May 16 '18 at 08:51

1

From the comments

i need to check if a in range of x and y or not.

Then do

a = "0.50"
x = "-14.40"
y = "0.50"

if float(x) <= float(a) <= float(y):  # checks a is between x and y (inclusive)
     # do something

range does something very different. It is for making iterators which we can use in for loops, like this:

for i in range(4):
    print(i * 2)
0
2
4
6

answered May 16 '18 at 08:51

FHTMitchell

Hermes Morales · Answer 3 · 2019-04-27T18:50:14.950

0

You can use numpy arange.

import numpy as np
r = np.arange(-14.4,0.5, 0.5)

def isinside(x):
if x in r:
    print ("x")
else:
    print ("x no in a")

isinside(-12)

returns

x no in a

If you want to print the whole serie

print ([round(x) for x in r])# round to avoid long numbers

edited Apr 27 '19 at 18:50

answered Apr 27 '19 at 18:33

Hermes Morales

3 Answers3