How to convert a string containing "/" to a float in Python

Question

I have some dimensions typed as a text in inches format, example: text = "20 7/8 16 1/4" # the first two represent, let's say, the length, and the second two represent the width I can change this string into a list of strings using text.split() to get: ["20", "7/8", "16", "1/4"].

Now, I want to add the first two items 20 + 7/8 to get 20.875. How can I convert 7/8 to a float number?

Since you're using python3, you can use [`eval`](https://docs.python.org/3/library/functions.html#eval): `map(eval, ["20", "7/8", "16", "1/4"])` — pault, Feb 22 '18 at 23:03
@roganjosh I know but it kind of works nicely here. Caveat for OP: [Why is eval bad](https://stackoverflow.com/questions/1832940/why-is-using-eval-a-bad-practice)? — pault, Feb 22 '18 at 23:04
@pault I guess it kinds works in a lot of places until... it works too well :P — roganjosh, Feb 22 '18 at 23:05

score 5 · Answer 1 · answered Feb 22 '18 at 23:03

5

A quick Google search can show you the answer

from fractions import Fraction
print float(Fraction('7/8'))

answered Feb 22 '18 at 23:03

Sevy

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score 1 · Accepted Answer · answered Feb 22 '18 at 23:06

1

>>> from __future__ import division
... 
... result = []
... text = "20 7/8 16 1/4"
... for num in text.split():
...     try:
...         numerator, denominator = (int(a) for a in num.split('/'))
...         result.append(numerator / denominator)
...     except ValueError:
...         result.append(int(num))
... 
>>> result
[20, 0.875, 16, 0.25]

answered Feb 22 '18 at 23:06

G_M

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Don't need `from __future__ import division` for python3 – pault Feb 22 '18 at 23:06
@pault You are correct. I just have a Python 2.7 project open in PyCharm so that is what console I'm currently using. Sometimes I also like using `operator.truediv` for Python 2/3 compatibility since it's very obvious. – G_M Feb 22 '18 at 23:09

score 1 · Answer 3 · answered Feb 22 '18 at 23:28

1

text = "7/8"
x = text.find("/")
numerator = float(text[0:x])
denominator = float(text[x+1:])
print(numerator/denominator)

answered Feb 22 '18 at 23:28

O. Mohsen

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Your answer was flagged as low quality because it lacks explanation. Expand upon why your answer works, or it will be deleted. – Derek Brown Feb 23 '18 at 05:39
The code is self-explaining .. take the number to the left of " / ", convert it to a float, take the number to the right of " / ", convert it to a float; then perform a normal division !! – O. Mohsen Sep 26 '18 at 18:52

whackamadoodle3000 · Answer 4 · 2018-02-22T23:11:07.023

0

How can I convert 7/8 to a float number?

a="7/8".split("/")
a=int(a[0])/int(a[1])

Or if you don't care about safety:

a=eval("7/8")

edited Feb 22 '18 at 23:11

answered Feb 22 '18 at 23:04

whackamadoodle3000

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score 0 · Answer 5 · answered Feb 22 '18 at 23:05

0

num = '7/8'.split('/')
dec = int(num[0]) / int(num[1])

answered Feb 22 '18 at 23:05

MalloyDelacroix

2,193
1
13
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Yes, it would work. – MalloyDelacroix Feb 22 '18 at 23:40

How to convert a string containing "/" to a float in Python

5 Answers5