在 python 的一行中查找小数

Question

I have a file with multiple lines like these:

hello check2check number 1235.67 thanks[4]
also 67907 another number of interest[45]

I am trying to find these numbers (float) in each line (they exist only once per line) but the last string might have integers in square brackets or an integer might exist before (as in check2check shown above)

1235.67
67907

import re

def updates (self, fileHandler,spec):
   for line in fileHandler:
      line_new = line.strip('\n')
      ll = line_new.split()
      l = len(ll)


   for i in range (l-1): 
            delay = re.search('\d*\.?\d+',i)

I keep getting this error:

TypeError: expected string or bytes-like object

Is this the correct way to look for the numerical values?

Answer 1

This for i in range (l-1) iterates over integers.

Use

for line in fileHandler:
  match = re.search(r'(?<!\S)\d*\.?\d+(?!\S)', line)
  if match:
    print(match.group())

In your class:

def updates (self, fileHandler, spec):
    results = []
    for line in fileHandler:
        match = re.search(r'(?<!\S)\d*\.?\d+(?!\S)', line)
        if match:
            results.append(match.group())
    return results

Remove spec if not needed.

Answer 2

One approach could apply

• a regex matching numbers ( (?<= |^)\d+(\.\d+)?(?= |$) ) in your string, using re.findall method
• the cast of each value to the float type, using Python built-in map function

on each of your string by iterating using a list comprehension.

import re

def updates (self, fileHandler,spec):
    return [map(float, re.findall('(?<= |^)\d+(\.\d+)?(?= |$)', line)[0]) for line in fileHandler]