How to extract numbers from a string in Python?

Question

I would extract all the numbers contained in a string. Which is the better suited for the purpose, regular expressions or the isdigit() method?

Example:

Answer 1

@jmnas, I liked your answer, but it didn't find floats. I'm working on a script to parse code going to a CNC mill and needed to find both X and Y dimensions that can be integers or floats, so I adapted your code to the following. This finds int, float with positive and negative vals. Still doesn't find hex formatted values but you could add "x" and "A" through "F" to the num_char tuple and I think it would parse things like '0x23AC'.

s = 'hello X42 I\'m a Y-32.35 string Z30'
xy = ("X", "Y")
num_char = (".", "+", "-")

l = []

tokens = s.split()
for token in tokens:

    if token.startswith(xy):
        num = ""
        for char in token:
            # print(char)
            if char.isdigit() or (char in num_char):
                num = num + char

        try:
            l.append(float(num))
        except ValueError:
            pass

print(l)