Pastetool - natural_sort

##  usage:
##  from natural_sort import natsort
##  print natsort(['a5', 'A7', 'a15', 'a9', 'A8'])

def try_int(s):
    "Convert to integer if possible."
    try: return int(s)
    except: return s

def natsort_key(s):
    "Used internally to get a tuple by which s is sorted."
    import re
    return map(try_int, re.findall(r'(\d+|\D+)', s))

def natcmp(a, b):
    "Natural string comparison, case sensitive."
    return cmp(natsort_key(a), natsort_key(b))

def natcasecmp(a, b):
    "Natural string comparison, ignores case."
    return natcmp(a.lower(), b.lower())

def natsort(seq, cmp=natcmp):
    "In-place natural string sort."
    seq.sort(cmp)
    return seq
    
def natsorted(seq, cmp=natcmp):
    "Returns a copy of seq, sorted by natural string sort."
    import copy
    temp = copy.copy(seq)
    natsort(temp, cmp)
    return temp