使用python解析文本文件，并在唯一的单词之间抓取单词

Question

I am trying to build a parser that will go through some SQL scripts and grab the data fields, tables etc. being used. I started it by trying to grab the field names. The SQL scripts all have a basic structure of:

select x,y,z,.. from table # sometimes it will be sel instead of select

This occurs usually multiple times in any script.

I have setup the below python code:

import csv
import re

def parser():                                     

           f=open('Book1.txt','r')
           data = f.read()
           print re.findall('sel.*from',data) 

I am only getting one of the select statements through this. Why is this not giving me all the texts between my select statements from which I can then parse through and determine the data fields being used? Maybe there is a better way to do this but I am hitting a wall.

Answer 1

Your regular expression is probably matching multiple select statements because it's working in greedy mode. Try using re.findall('sel.*?from', data) instead.