CODEWITHSUNDEEP
pythonpython-3.x
catzen
catzen

Reputation: 75

How to turn string decimals into float?

my_list=[['A','B','C','0.0'],['D','E','F','1.2'],['G','H','I','0'],['J','K','L','M']]

I tried these but they can only convert whole numbers into floats and leaves the rest as strings.

[[float(x) if x.isnumeric() else x for x in i] for i in my_list]

for i, sublist in enumerate(my_list):
     for j, x in enumerate(sublist):
            if x.isnumeric():
                my_list[i][j] = float(x)

Expected output

[['A','B','C',0.0],['D','E','F',1.2],['G','H','I',0],['J','K','L','M']]

Upvotes: 0

Views: 98

Answers (3)

Chase
Chase

Reputation: 5615

.isnumeric does not return True for float numbers represented as strings. It returns true for strings that only consists of numbers, . is not a number.

This is why your solution only converts integers, not floats.

The best choice to check if a string is a float, and hence convert it - is to just try float() and catching the raised ValueError and simply continuing.

If you know the nesting is only one level deep, deceze's solution should do it great.

If there may be more nesting, you could try a recursive function-

def convert_float(l: list):
    for i, v in enumerate(l):
        if type(v) == list:
            convert_float(v)
            continue
        try:
            l[i] = float(v)
        except ValueError:
            continue

Upvotes: 0

Mayank Porwal
Mayank Porwal

Reputation: 34046

You can also use regex to find this. Something like below:

In [105]: import re

In [106]: r = re.compile(r"^\d*[.,]?\d*$")

In [107]: [[float(v) if r.match(v) else v for v in l] for l in my_list]
Out[107]: 
[['A', 'B', 'C', 0.0],
 ['D', 'E', 'F', 1.2],
 ['G', 'H', 'I', 0.0],
 ['J', 'K', 'L', 'M']]

Upvotes: 0

deceze
deceze

Reputation: 522032

If you have no other criterion than "anything might or mightn't be a valid float", then just try them all:

def try_float(value):
    try:
        return float(value)
    except ValueError:
        return value

result = [[try_float(v) for v in l] for l in my_list]

Upvotes: 2

Related Questions