Use an iterator of octet quadruples instead of building a list of string...

pingrange.py

@@ -21,34 +21,39 @@
 # python pingrange.py 10.1.0-1.0-255 will ping 10.1.0.0/23
 #
 #
+import itertools
 import re
 try:
-        from cli import cli
+    from cli import cli
 except ImportError:
-        from cisco import cli
+    from cisco import cli
 from argparse import ArgumentParser
 
-def expandrange(rangefunc):
-    hosts = []
-    octets = rangefunc.split('.')
-    for i,octet in enumerate(octets):
-        if '-' in octet:
-            octetrange = octet.split('-')
-            for digit in range(int(octetrange[0]), int(octetrange[1])+1):
-                ip = '.'.join(octets[:i] + [str(digit)] + octets[i+1:])
-                hosts += expandrange(ip)
-            break
-    else:
-        hosts.append(rangefunc)
-    return hosts
+
+def parse_octet_ranges(octet_ranges_spec):
+    """
+    Parses IP range spec into four iterables of numbers corresponding to each
+    octet's range.
+    """
+    octet_ranges = [
+        [int(n) for n in octet_range.split('-')]
+        for octet_range in octet_ranges_spec.split('.')
+    ]
+    return [
+        octet_range if len(octet_range) == 1
+        else range(octet_range[0], octet_range[1] + 1)
+        for octet_range in octet_ranges
+    ]
+
 
 parser = ArgumentParser('pingrange')
 parser.add_argument('ip', help='IP range to ping, e.g., 10.1.0-1.0-255 will expand to 10.1.0.0/23')
 parser.add_argument('options', nargs='*', help='Options to pass to ping', default=['count 1'])
 args = parser.parse_args()
-targets = expandrange(args.ip)
+a_range, b_range, c_range, d_range = parse_octet_ranges(args.ip)
 
-for ip in targets:
+for a, b, c, d in itertools.product(a_range, b_range, c_range, d_range):
+    ip = '%d.%d.%d.%d' % (a, b, c, d)
     m = re.search('([0-9\.]+)% packet loss', cli('ping %s %s' % (ip, ' '.join(args.options))))
     print('%s - %s' % (ip, 'UP' if float(m.group(1)) == 0.0 else 'DOWN'))