In Python, how do I convert all of the items in a list to floats?

I have a script which reads a text file, pulls decimal numbers out of it as strings and places them into a list.

So I have this list:

['0.49', '0.54', '0.54', '0.54', '0.54', '0.54', '0.55', '0.54', '0.54',  '0.54', 
 '0.55', '0.55', '0.55', '0.54', '0.55', '0.55', '0.54', '0.55', '0.55', '0.54']

How do I convert each of the values in the list from a string to a float?

I have tried:

for item in list:
    float(item)

But this doesn't seem to work for me.