#!/usr/bin/env python
# specialrange.py
"""
Contains a general purpose object for arbitrary ranges
i.e.
a-z = abcdefghijklmnopqrstuvwxyz
A-Z = ABCDEFGHIJKLMNOPQRSTUVWXYZ
1-9 = 123456789
0-9 = 0123456789
0-1000 = 0123456789...1000
Copyright 2011 by Sunjay Varma. All Rights Reserved.
Check out www.sunjay.ca
"""
LOWERCASE = "abcdefghijklmnopqrstuvwxyz"
UPPERCASE = LOWERCASE.upper()
LETTERS = LOWERCASE+UPPERCASE
NUMBERS = "123456789"
try:
basestring
xrange
except NameError:
basestring = str
xrange = range
class irange(object):
def __init__(self, start, stop=None, step=1):
if stop is None:
stop = start
start = 0
if not isinstance(start, (float, int)) and not isinstance(stop, (float, int)) and \
type(start) != type(stop):
raise TypeError("The types of start and stop must be the same!")
try:
if "." in start:
start = float(start)
else:
start = int(start)
if "." in stop:
stop = float(stop)
else:
stop = int(stop)
except (ValueError, TypeError):
pass # will be handled later
if isinstance(start, basestring): # the types of start and stop will be the same
assert len(start) and len(stop), "There must be at least one character!"
if len(start) > 1 or len(stop) > 1:
raise ValueError("Longer start and stop values are unsupported!")
if start in LETTERS and stop in LETTERS:
self.iterrange = self._char_range(start, stop, step)
else:
self._cannot_understand(start, stop, step)
elif isinstance(start, (float, int)):
self.iterrange = self._number_range(start, stop, step)
else:
self._cannot_understand(start, stop, step)
def _cannot_understand(self, start, stop, step):
raise ValueError("Cannot understand: %s, %s, or %s"%(start, stop, step))
@staticmethod
def _in_seq(seq, *args):
for x in args:
if x not in seq:
return False
return True
def _char_range(self, start, stop, step):
is_lower = self._in_seq(LOWERCASE, start, stop)
if not(is_lower or self._in_seq(UPPERCASE, start, stop)):
raise ValueError("start and stop must both be in the uppercase or lowercase letters")
seq = is_lower and LOWERCASE or UPPERCASE
start_i = seq.index(start)
stop_i = seq.index(stop)
delta = abs((start_i - stop_i) // step) #+ 1 # the +1 will give even the last character in the result
if stop_i < start_i and step >= 0 or stop_i > start_i and step <= 0:
# the number will never reach
return iter([])
return (seq[start_i + step * i] for i in xrange(delta))
@staticmethod
def _number_range(start, stop, step):
if stop < start and step >= 0 or stop > start and step <= 0:
# the number will never reach
return iter([])
delta = abs((start - stop) // step)
return (start + step * i for i in xrange(int(delta)))
def __iter__(self):
return self
def next(self):
return self.iterrange.next()
def __next__(self): # py3
return self.iterrange.__next__()
srange = lambda start, stop=None, step=1: list(irange(start, stop, step))
Diff to Previous Revision
--- revision 2 2011-02-26 23:36:01
+++ revision 3 2011-03-30 16:42:47
@@ -21,8 +21,11 @@
try:
basestring
+ xrange
+
except NameError:
basestring = str
+ xrange = range
class irange(object):
