正则表达式以匹配括号内的数字

Question

I have problem in extraction of certain data in the following program where it has been marked with bold and italics. I want to extract those data from a file and process it as follows.

i 1CAT(0)

i 2CAT(1)

o 22CAT(10)

o 23CAT(9)

g1 ***and*** 6CAT(**3**) 3CAT(**2**) ; 11CAT(**5**)

g2 ***or*** 3CAT(**2**) 1CAT(**0**) ; 10CAT(**16**)

Example:

line 5: if(and) appears then do 3+2*5

line 6: if(or) appears then do 2-0+16

etc....

Code till now:

import os
os.chdir('/home/pr/Documents/')
inputFile=open('C17.txt','r')
inputfile.readline()
print inputFile.read()
inputFile.close()

Answer 1

You need to distinguish between braces you want to match in the string and braces that belongs to your regular expression.

All kind of braces have a special meaning for a regular expression, so if you want to match them, you need to escape them.

Regarding your regex from your comment

re.findall(r'(0-9)',inputFile)

• re.findall (link) , needs a string as second argument and not a file handle.

• (0-9) is just matching one digit and because the brackets aren't escaped the value is stored in a capturing group. (Check here the paragraph (...) ) . If you want to match numbers with more than one digit at once, you should have a look into quantifiers ( + , * , {m,n} same link than before).

Regarding your code in the OP

You are aware that the code you presented has not much to do with the task (except the file opening and closing). You may want to have a look at the Python tutorial about "Reading and Writing Files"