CODEWITHSUNDEEP
pythonpython-3.x
Tronald Dump
Tronald Dump

Reputation: 1350

clean up an input to numbers and decimals

I am trying to clean up some user input to a valid float type with only numbers and decimal points.

I found this approach

def to_numeric(s):
    try:
        s = str(s).strip()
        if s is None or len(s) < 1:
            return None
        else:
            s = ''.join(filter(lambda x: x in '.0123456789', str(s)))
            if s is None or len(s) < 1:
                return None
            else:
                s = float(s)
                return s

    except ValueError as detail:        
        return None

    except Exception as detail:        
        return None

But the cast to float complains of

float() argument must be a string or a number, not 'filter'

How can I get the string back from the filter?

Upvotes: 2

Views: 914

Answers (2)

standy
standy

Reputation: 1065

Use 

s = float("".join(s))

instead of

s = float(s)

In Python 3, filter returns an iterator and float expects str

Upvotes: 0

Uriel
Uriel

Reputation: 16184

filter returns an iterable that yields single chars for that case (it iterates over the string and yields acceptable characters). Try using ''.join to make them come back as a string:

s = ''.join(filter(lambda x: x in '.0123456789', str(s)))
s = float(s)

Upvotes: 3

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