[Tutor] Parsing Bible verses

[C or L Smith]

Here is something from my toolbox of routines that might be useful for the number ranges:

>>> indices('-5--2')
[-5, -4, -3, -2]
>>> indices('3-4')
[3, 4]
>>> indices('3-4,10')
[3, 4, 10]

/chris

def indices(s,n=None): #("1-3,7")->1,2,3,7;i("1,-3--1")->1,-3,-2,-1; or (slc,n=None)->slc.start,stop,step [for range(n)]
    """Return a list of indices as defined by a MSWord print dialog-like range:
    
    e.g. "1,3,5-7" -> [1, 3, 5, 6, 7]
    
    A trailing comma will be ignored; a trailing dash will generate an error."""

    # ranges must be increasing: -3--4 will not generate any numbers
    assert type(s) is str
    r=[x.strip() for x in s.split(',')]
    rv = []
    for ri in r:
        if not ri: continue
        if ri.find('-',1)>0: #ignore - in first position
            dashat = ri.find('-',1) #start searching at position 1
            nums = ri[:dashat],ri[dashat+1:]
            #one might want to use sys.maxint-1 for stop if the '-' is encountered, the
            #meaning being "from start to the end (as defined by the code elsewhere")
            #but then this should be made into an iterator rather than generating the
            #whole list
            if nums[1] in ['','-']:
                raise ValueError('missing number in request to indices: %s'%ri)
            start, stop = [int(x.strip()) for x in nums]
            for i in xrange(start, stop+1):
                rv.append(i)#yield i
        else:
            rv.append(int(ri))#yield int(ri)
    return rv