Convert from numbers to letters

[rh0dium]

Hi All,

While I know there is a zillion ways to do this.. What is the most
efficient ( in terms of lines of code ) do simply do this.

a=1, b=2, c=3 ... z=26

Now if we really want some bonus points..

a=1, b=2, c=3 ... z=26 aa=27 ab=28 etc..

Thanks

[rh0dium]

Python 2.3.5 (#1, Mar 20 2005, 20:38:20)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1809)] on darwin

Traceback (most recent call last):
File "<stdin>", line 1, in ?
NameError: name 'sorted' is not defined

I think you're probably using 2.4 ??

[Bill Mill]

On 19 May 2005 12:20:03 -0700, rh0dium <sk****@pointci rcle.com> wrote:

Python 2.3.5 (#1, Mar 20 2005, 20:38:20)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1809)] on darwin

Traceback (most recent call last):
File "<stdin>", line 1, in ?
NameError: name 'sorted' is not defined

I think you're probably using 2.4 ??
Yes, sorted() is new in python 2.4 .You could use a very lightly
tested pure-python partial replacement:

def sorted(lst, **kwargs):
l2 = lst[:]
if kwargs.has_key( 'key'):
f = kwargs['key']
l2.sort(lambda a,b: cmp(f(a), f(b)))
return l2
l2.sort()
return l2

And from your other email: I need to go the other way! tuple2coord

Sorry, I only go one way. It should be transparent how to do it backwards.

Peace
Bill Mill
bi*******@gmail .com

[Peter Otten]

Bill Mill wrote:

Traceback (most recent call last):
File*"<stdin> ",*line*1,* in*?
NameError: name 'sorted' is not defined

I think you're probably using 2.4 ??

Yes, sorted() is new in python 2.4 .You could use a very lightly
tested pure-python partial replacement:

By the way, sorted() can be removed from your original post.

Code has no effect :-)

Peter

[Bill Mill]

On 5/19/05, Peter Otten <__*******@web. de> wrote:

Bill Mill wrote:

Traceback (most recent call last):
File"<stdin>" ,line1,in?
NameError: name 'sorted' is not defined

I think you're probably using 2.4 ??

Yes, sorted() is new in python 2.4 .You could use a very lightly
tested pure-python partial replacement:

By the way, sorted() can be removed from your original post.

Code has no effect :-)

I'm gonna go ahead and disagree with you:

sorted([''.join((x, y)) for x in alpha \ .... for y in [''] + [z for z in alpha]], key=len) == \
.... [''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]]
False

If you want to see why, here's a small example:
alpha = 'abc'
[''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]] ['a', 'aa', 'ab', 'ac', 'b', 'ba', 'bb', 'bc', 'c', 'ca', 'cb', 'cc']
sorted([''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]],

key=len)
['a', 'b', 'c', 'aa', 'ab', 'ac', 'ba', 'bb', 'bc', 'ca', 'cb', 'cc']

Peace
Bill Mill
bill.mill at gmail.com

[Gary Wilson Jr]

Bill Mill wrote:

On 5/19/05, Peter Otten <__*******@web. de> wrote:

Bill Mill wrote:

Traceback (most recent call last):
File"<stdin >",line1,in?
NameError : name 'sorted' is not defined

I think you're probably using 2.4 ??

Yes, sorted() is new in python 2.4 .You could use a very lightly
tested pure-python partial replacement:
By the way, sorted() can be removed from your original post.

Code has no effect :-)

I'm gonna go ahead and disagree with you:

Me too, although I would forgo the sort altogether (while making things
a little more readable IMO):
alpha = 'abcdefghijklmn opqrstuvwxyz'.u pper()
pairs = [''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]]
pairs = sorted(pairs, key=len)

alpha = 'abcdefghijklmn opqrstuvwxyz'.u pper()
pairs = [x for x in alpha] + [''.join((x,y)) for x in alpha for y in alpha]

[Peter Otten]

Bill Mill wrote:

By the way, sorted() can be removed from your original post.

Code has no effect :-)

I'm gonna go ahead and disagree with you:

sorted([''.join((x, y)) for x in alpha \ ...****for*y*in *['']*+*[z*for*z*in*alph a]],*key=len)*==*\
... [''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]]
False

That's not your original code. You used the contents to modify the locals()
(effectively globals()) dictionary:

alpha = 'abcdefghijklmn opqrstuvwxyz'
for i, digraph in enumerate(sorte d([''.join((x, y)) for x in alpha \ for*y*in*['']*+*[z*for*z*in*alph a]],*key=len)):
...*****locals( )[digraph]*=*i*+*i
...

Of course you lose the order in that process.
When you do care about order, I suggest that you swap the for clauses
instead of sorting, e. g:

alpha = list("abc")
items = [x + y for x in [""] + alpha for y in alpha]
items == sorted(items, key=len)

True

Peter

[Peter Otten]

Peter Otten wrote:

[Something stupid]

You are right. I finally got it.

Peter

[Jason Drew]

We weren't really backwards; just gave a full solution to a half-stated
problem.

Bill, you've forgotten the least-lines-of-code requirement :-)

Mine's still a one-liner (chopped up so line breaks don't break it):

z = lambda cp: (int(cp[min([i for \
i in xrange(0, len(cp)) if \
cp[i].isdigit()]):])-1,
sum(((ord(cp[0:min([i for i in \
xrange(0, len(cp)) if \
cp[i].isdigit()])][x])-ord('A')+1) \
* (26 ** (len(cp[0:min([i for i in \
xrange(0, len(cp)) if \
cp[i].isdigit()])])-x-1)) for x in \
xrange(0, len(cp[0:min([i for i in \
xrange(0, len(cp)) if \
cp[i].isdigit()])]))))-1)

print z("B14")
# gives (13, 1)

Maybe brevity isn't the soul of wit after all ...

[Mike Meyer]

Bill Mill <bi*******@gmai l.com> writes:

On 19 May 2005 11:59:00 -0700, rh0dium <sk****@pointci rcle.com> wrote:

This is great but backwards...

Ok because you all want to know why.. I need to convert Excel columns
A2 into , [1,0] and I need a simple way to do that..

( The way this works is A->0 and 2->1 -- Yes they interchange -- So
B14 == [13,1] )

why didn't you say this in the first place?

def coord2tuple(coo rd):
row, col = '', ''
alpha = 'abcdefghijklmn opqrstuvwxyz'.u pper()
pairs = [''.join((x,y)) for x in alpha for y in [''] + [z for z in alpha]]
pairs = sorted(pairs, key=len)
coord = coord.upper()
for c in coord:
if c in alpha:
row += c
else:
col += c
return (int(col)-1, pairs.index(row ))

That seems like the long way around. Python can search strings for
substrings, so why not use that? That gets the search loop into C
code, where it should be faster.

from string import uppercase

def coord2tuple2(co ord):
if len(coord) > 1 or uppercase.find( coord) < 0:
raise ValueError('coo rd2tuple2 expected a single uppercase character, got "%s"' % coord)
return uppercase.index (coord) + 1

Without the initial test, it has a buglet of return values for "AB"
and similar strings. If searching uppercase twice really bothers you,
you can drop the uppercase.find; then you'll get less informative
error messages if coord2tuple2 is passed single characters that aren't
in uppercase.

<mike
--
Mike Meyer <mw*@mired.or g> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

[Gary Wilson Jr]

Gary Wilson Jr wrote:

alpha = 'abcdefghijklmn opqrstuvwxyz'.u pper()
pairs = [x for x in alpha] + [''.join((x,y)) for x in alpha for y in alpha]

I forget, is string concatenation with '+' just as fast as join()
now (because that would look even nicer)?