very good reasons?
Grant Griffin
g2 at seebelow.org
Fri Sep 29 13:37:27 EDT 2000
Hi Gang,
I was trying to chain "sort" and "reverse" together the other day <<confess>>,
ala Perl, but I found that it didn't work, e.g.:
Python 2.0b2 (#6, Sep 26 2000, 14:59:21) [MSC 32 bit (Intel)] on win32
>>> a=[1,2,3,4]
>>> b=a.sort().reverse()
Traceback (most recent call last):
File "<stdin>", line 1, in ?
AttributeError: 'None' object has no attribute 'reverse'
>>> c=a.sort()
>>> repr(c)
'None'
I would have expected sort and reverse to return the list in question, but
instead they return None. So I had to do something like:
>>> a=[1,2,3,4]
>>> a.sort()
>>> a.reverse()
>>> b=a
>>> b
[4, 3, 2, 1]
Likewise, I wondered the other day why "real" and "imag" are "attributes" of
complex numbers instead of functions:
>>> a=1+2j
>>> a.imag
2.0
>>> a.real
1.0
Then I realized <head slap!>, that it must be so you could _assign_ to them:
Hey, that sounds kindda useful! However:
>>> a.real = 5
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: object has read-only attributes
>>> a.imag = 6
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: object has read-only attributes
Having faith in our BDFL as I do, I'm sure there are very good reasons for these
things. Does anybody know what they are?
hoping-for-more-head-slaps-<<endorphins>>-ly y'rs,
=g2
_____________________________________________________________________
Grant R. Griffin g2 at dspguru.com
Publisher of dspGuru http://www.dspguru.com
Iowegian International Corporation http://www.iowegian.com
More information about the Python-list
mailing list