How to callthe first float in a list in Python

Question

In Python if I have numerous lines of data containing both strings and floats (sample below) which I have tokenized, how can I call the first float value in each line if this position is not constant? I eventually want to use this as a reference point for latter tokens. Thanks in advance.

F + FR > FR* + F + E 11.60 0 2 FR > FR*

F + FR > FR*** + F 11.60 0 2382 FR > FR***

And what do you mean by "call"? Numbers are not callable (you can't say `123()`), do you want to store it in a variable, or print it? — tripleee, Mar 17 '14 at 15:55
Not worthy of a full answer, but generally after tokenizing you would convert the individual tokens into a parse tree, then you would traverse the parse tree to interpret the statement. Read up on PLY or ANTLR or any other lexer/parser type subsystems. — Joe Holloway, Mar 17 '14 at 16:03

score 0 · Accepted Answer · answered Mar 17 '14 at 16:21

You can use the re module. Just import it and look for digits with a . within them. For example,

import re
def findFloat(s): 
    return float( re.search('[0-9]+.[0-9]+', s).group() )

This finds the first occurrence of a group of numbers separated by a .

How to callthe first float in a list in Python

1 Answers1