large_file_python_iterate_method1.py

'''
Created on Jul 20, 2016
'''

import re


def main():
    f_path1 = "[the file path of big data file]"

    f1 = open(f_path1)


    ct = 0
    ptn1 = ".*?\d+0000000000000000(.*?)\s+(\d{4}\.)\s+0\..*?"
    ptn2 = ".*?\s+0000000000000000(.*?)\s+(\d{4}\.)\s+0\..*?"
    ptn3 = ".*?\d+0000000000000000(.*?)0\..*?"
    ptn4 = ".*?\s+0000000000000000(.*?)0\..*?"
    all_merchant = []
    epts = []


    for l in f1:
        ct += 1
        if ct == 501: break
        m1 = re.search(ptn1, l)
        
        if m1 != None:
            all_merchant.append(m1.group(1))
            print len(all_merchant)
            continue
        else:
            m2 = re.search(ptn2, l)
            if m2 != None:
                all_merchant.append(m2.group(1))
                print len(all_merchant)
                continue
            else:
                m3 = re.search(ptn3, l)
                if m3 != None:
                    epts.append(m3.group(1))
                    continue
                else:
                    m4 = re.search(ptn4, l)
                    if m4 != None:
                        epts.append(m4.group(1))
                        continue
                    else: print l
        
    

if __name__ == "__main__":
    main()