Else statement did not get executed

I have a text file that reads. I managed to get everything sorted but what I don't understand is that my code did not get executed in the else statement. (The Else statement will skip the useless data and will not add to the PriorityQueue.)

id_is_g0000515

num_is_0.92

id_is_g0000774

uselessdata2

num_is_1.04

hithere

id_is_g0000377

num_is_1.01

pt21

id_is_g0000521

num_is_5.6

import os, sys, shutil, re


def readFile():
    from queue import PriorityQueue
    str1 = 'ID_IS'
    str2 = 'NUM_IS'
    q = PriorityQueue()
    #try block will execute if the text file is found
    try:
        fileName= open("Real_format.txt",'r')
        for line in fileName:
                for string in line.strip().split(','):
                    if string.find(str1): #if str1 is found
                        q.put(string[-4:]) #store it in PQ
                    elif string.find(str2):#if str2 is found
                        q.put(string[-8:]) #store it in PQ
                    else:
                        line.skip() #skip the useless string
                        #q.remove(string)

        fileName.close() #close the file after reading          
        print("Displaying Sorted Data")
        #print("ID TYPE       Type")
        while not q.empty():
            print(q.get())

            #catch block will execute if no text file is found
    except IOError:
                print("Error: FileNotFoundException")
                return

readFile()