Most elegant way to generate 3-char sequence

[Rob Cowie]

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

x = generate()
x.next() # etc, etc, etc,

[James Stroud]

Rob Cowie wrote:

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

x = generate()
x.next() # etc, etc, etc,

import string
alpha = string.lowercas e

def generator(choic es, length):
for a in choices:
if length > 1:
for g in generator(choic es, length-1):
yield a + g
else:
yield a

for a in generator(alpha , 3):
print a
--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

[James Stroud]

Rob Cowie wrote:

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

x = generate()
x.next() # etc, etc, etc,

A touch more efficient:

import string
alpha = string.lowercas e

def generator(choic es, length):
length -= 1
for a in choices:
if length:
for g in generator(choic es, length):
yield a + g
else:
yield a

for a in generator(alpha , 3):
print a

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

[David Isaac]

"Rob Cowie" <co*******@gmai l.com> wrote in message
news:11******** **************@ h76g2000cwa.goo glegroups.com.. .

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

Basically fine, but you only need one string. E.g.,
alpha = "abcd"
used three times.

Alan Isaac

[Grant Edwards]

On 2006-06-09, Rob Cowie <co*******@gmai l.com> wrote:

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

Why three separate lists? Why not

alpha = ['a','b','c','d'] #shortened for brevity

def generator():
for char in alpha:
for char2 in alpha:
for char3 in alpha:
yield char + char2 + char3

--
Grant Edwards grante Yow! I think I am an
at overnight sensation right
visi.com now!!

[John Machin]

On 10/06/2006 7:49 AM, Rob Cowie wrote:

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...
You're not wrong.

alpha = ['a','b','c','d'] #shortened for brevity
Hope you remember the alphabet correctly.
Why type all that punctuation?
Any reason this cruft is global (i.e. not local to the generator)?
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']
Hope you get the redundant copy/paste right.

def generator():
for char in alpha:
Why stop at two spaces? One-space indentation is syntactically correct :-)
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

x = generate()
Did you meant "generator" ?
x.next() # etc, etc, etc,

|>> def generator():
.... import string
.... alpha = string.ascii_lo wercase
.... for char in alpha:
.... for char2 in alpha:
.... for char3 in alpha:
.... yield char + char2 + char3
....
|>> x = generator()
|>> the_lot = list(x)
|>> len(the_lot) == 26 ** 3
True
|>> [the_lot[i] for i in (0, 1, 25, 26, -27, -26, -1)]
['aaa', 'aab', 'aaz', 'aba', 'zyz', 'zza', 'zzz']

Cheers,
John

[David Isaac]

alpha = string.lowercas e
x=(a+b+c for a in alpha for b in alpha for c in alpha)

[James Stroud]

Rob Cowie wrote:

Hi all,

I wish to generate a sequence of the form 'aaa', 'aab', aac'.... 'aba',
'abb', 'abc' etc. all the way to 'zzz'.

How would you construct a generator to acheive this?

A simple, working but somewhat inelegant solution is...

alpha = ['a','b','c','d'] #shortened for brevity
alpha2 = ['a','b','c','d']
alpha3 = ['a','b','c','d']

def generator():
for char in alpha:
for char2 in alpha2:
for char3 in alpha3:
yield char + char2 + char3

x = generate()
x.next() # etc, etc, etc,

Yet a little more efficient.

import string
alpha = string.lowercas e

def generator(choic es, length):
length -= 1
if length:
for a in choices:
for g in generator(choic es, length):
yield a + g
else:
for a in choices:
yield a

for a in generator(alpha , 3):
print a

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

[SuperHik]

and the winner is... :D
David Isaac wrote:

alpha = string.lowercas e
x=(a+b+c for a in alpha for b in alpha for c in alpha)

[James Stroud]

SuperHik wrote:

and the winner is... :D
David Isaac wrote:

alpha = string.lowercas e
x=(a+b+c for a in alpha for b in alpha for c in alpha)

Not necessarily vying for winner, but David's solution is highly
specific as it doesn't do so well for something like

aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aaa
aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aaaaaaaaaaaaaaa aab
..
..
..
zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzy
zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzzzzzzzzzzzzzz zzz
James

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/