CODEWITHSUNDEEP
python
scwat
scwat

Reputation: 45

How can I make this function count the number of digits in a float?

I am creating a function that takes a number and prints the number of digits in the number. I have it working for ints but I want it to work for floats, too. I know it's simple but I am a beginner. I tried using int(float(num)) but that produced an error (ValueError: could not convert string to float: '-f'). I also tried using .replace but that didn't work. Any hints? Thank you

import sys

def digits(num):
    count = len(num)
    return count

num = sys.argv[1]
count = digits(num)
print(digits(num))

Upvotes: 1

Views: 2769

Answers (3)

Vladyslav Chaikovskyi
Vladyslav Chaikovskyi

Reputation: 326

If you just want to count how many values are in the number you can modify your code as follows (only for positive floats and integers)

count = len(num.replace('.', ''))

To work around with negative values you can use json module. It will cover you mantisa case.

import json
def count_digits(num):
    num = json.loads(num) # returns type bound value
    digit_str = str(abs(num)).replace('.', '')
    return len(digit_str)

Try:

my_float = '1e+30'
actual_float = json.loads(my_float)
print(type(actual_float)) # returns <class 'float'>

Notice: json.loads works only with string objects, so you're good to go with applying this function to your arguments as they are strings by default.

You can also use re module (regular expressions):

import re
def count_digits(num):
    return len(re.sub(fr'[.+-]', '', num))

Here you use re.sub to substitute ., +, and - sign for nothing and return the length of the resulting string. Notice: with re module you're working with strings!

The last approach I can come up with is by using eval function

eval('-1e+15')

Upvotes: 1

Raul Gomez
Raul Gomez

Reputation: 11

Your function is not working with int nor float it is all strings

So i would say you should subtract 1 to the count if there is a decimal point

Try this:

def digits(num):
    count = len(num) if '.' not in num else len(num) - 1
    return count

Upvotes: 0

David Scholz
David Scholz

Reputation: 9836

Try this function

def getDigitCount(input):
    s=str(abs(input))
    t=-1 if "." in s else 0
    return len(s) + t

Use it as follows

getDigitCount(2312.5262627)

which yields to 11. Notice, that this works for negative floats as well.

getDigitCount(-2312.5262627)

which also yields to 11 as desired.

Upvotes: 0

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