Q: Why does this work???

[Jim Cerra]

I'm very new to Python, and I've been examing a bit of code... I can't
figure out why the following doesn't produce an error:

# begin code
# ----------------------------

import string

# --- Global variables

total_hits   = 0
hits_by_page = {}  # maps document URL to hit count for that document

# --- Functions

def read_logfile(filename):
    inf = open(filename)

    line = inf.readline()
    while line != "":
        fields = string.split(line)
        process_request(fields[0], fields[3], fields[4], fields[5],
fields[6],
                        fields[7], fields[8], fields[9])

        line = inf.readline()

    inf.close()

def process_request(host, date, timezone, method, url, protocol, code,
bytes):
    global total_hits


    if code > "399": return # request was not successful, so don't count it

    total_hits = total_hits + 1

    url = string.split(url, "?")[0] # remove script arguments, if any

    if hits_by_page.has_key(url):
        hits_by_page[url] = hits_by_page[url] + 1
    else:
        hits_by_page[url] = 1

report_top = \
"""
<title>Web server statistics</title>
<h1>Web server statistics</h1>
<table>
<tr><th>Total number of hits:  <td>%d
<tr><th>Total number of pages: <td>%d
</table>
"""

def produce_report():
    print report_top % (total_hits, len(hits_by_page))

    pages = []
    for (url, hits) in hits_by_page.items():
        pages.append((hits, url))
    pages.sort()
    pages.reverse()

    print "<table>"
    print "<tr><th>Page   <th>Hits"
    for (hits, url) in pages:
        print "<tr><td>%s <td>%d" % (url, hits)
    print "</table>"


# --- Main program

import sys

if len(sys.argv) != 2:  # script name is sys.argv[0]
    print "Usage: %s <log file name>" % sys.argv[0]
    sys.exit(1)

read_logfile(sys.argv[1])
produce_report()


# ----------------------------
# end code

In the function, process_request(), why isn't the variable, hits_by_page,
declared as a global var?  I tried putting in that code ("    global
hits_by_page") and there is no effect.  The script still works.

My question is Why???

Please excuse any ignorance on my part; Python is not my native programming
language. ;-)

--
Jimmy Cerra
"my mind is slipping away ... day by glorious day" - RG