How to deal with commas for decimal AND thousand separator

Question

Due to reasons that are not important here, I have an excel sheet where my numbers have commas for decimal points as well as thousands separators. The only way to differentiate if the comma is supposed to be a decimal or a thousands separator, is the number of digits after the comma:

decimal = 7,29
thousands = 23,767,209

My approach, which works fine for my case, is to read in the numbers as strings and execute the following code:

strings = ["0", "87,390,112", "78", "9,27", "1"]
strings_new = []

for i in strings:
    if len(i) >= 3:
        # check if third last char is a comma --> decimal
        if i[-3] == ',':
            i = i[:-3] + '.' + i[-3 + 1:]              
    if len(i) >= 4:
        # check if fourth last char is a comma --> all commas are thousands
        if i[-4] == ',':
            i = i.replace(",", "")

    strings_new.append(i)

strings_new = [float(i) for i in strings_new]

And the output looks fine:

strings_new = [0.0, 87390112.0, 78.0, 9.27, 1.0]

Are there any special cases this code is missing that I haven't thought of? And is there maybe a more efficient way to deal with this problem?

Answer 1

Two cases:

1. If the decimal is only one digit: 100,1 . Use i.rfind(',') to get the comma position instead of hard-coding it with -3 .

2. If it contains both conditions: 10,000,24 . It will slip through the second if-clause ( 10,000.24 ). Always running i.replace(",", "") without the if-clause should be fine.