how to split the digits of pi into a list

Question

I am plotting the digits of pi on a matplotlib graph, however in order to do this I must split the digits into individual integers. I am using math.pi for this, is there any other way I could do it to make it easier?

I think .split() only works on strings however I may be wrong.

How do you mean *split the digits into individual integers*? — Moses Koledoye, Dec 12 '16 at 21:24
You have a float and would like to split the digits into a list? — Elliot Roberts, Dec 12 '16 at 21:25
`math.pi` won't give you many digits. Here is a function that will return as many digits as you want, in a string: http://stackoverflow.com/a/40834329/4996248 — John Coleman, Dec 12 '16 at 21:29
Exact dupe of [Separate float into digits](http://stackoverflow.com/questions/29770437/separate-float-into-digits) — chickity china chinese chicken, Dec 12 '16 at 21:30

score 1 · Accepted Answer · answered Dec 12 '16 at 21:28

You are correct that strings have a .split() method and doubles do not.

I think you are thinking about the number as a string, though. Numbers don't really have separate digits, except in their textual representation in some base. So, you could convert the number to a string and go from there.

Eg.

text = "%.20f" % math.pi
digits = [int(s) for s in text if s != "."]
print(digits)

Max · Answer 2 · 2016-12-12T21:31:02.540

1

Do you want to split each digit into a list? If so, I would convert it to a string (since numbers are treated as the number itself and not digits that make it up) Then remove the decimal point by making a list that excludes decimal points.

import math

listOfDigits = [item for item in str(math.pi) if item != "."]

edited Dec 12 '16 at 21:31

answered Dec 12 '16 at 21:28

Max

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loose the `list()`, `str()` is iterable – Dalvenjia Dec 12 '16 at 21:29
1

Or `list(str(math.pi).replace('.', ''))` – Moses Koledoye Dec 12 '16 at 21:33
that is also a valid way to do it. – Max Dec 12 '16 at 21:34
Somebody downvoted it - may I ask what was bad about my answer? So that I can improve next time. – Max Dec 12 '16 at 22:32

Scott Colby · Answer 3 · 2016-12-12T22:00:26.240

You can do this with a generator:

def split_number(number):
    number_as_string = str(number)
    for character in number_as_string:
        if not character.isdigit():
            continue
        yield int(character)

import math
print(list(split_number(math.pi)))
# [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 9]

Or if you prefer a one-liner:

list(int(character) for character in str(math.pi) if character.isdigit())
# or
[int(character) for character in str(math.pi) if character.isdigit()]

I believe these answers are preferable because of the use of isdigit instead of special-casing only the . character.

how to split the digits of pi into a list

3 Answers3