read/ edit line from stdin
Hello, for my project confux (http://confux.sourceforge.net) I want to read a line from stdin. But I don't want the user to type a new line. I want so display a value which the user can edit. For example I want to ask the user for a hostname and I print "localhost", the user modified it to "localserver" and I read it after . What is the fastest way to realize that? I do NOT want to use curses (yet) ;-). mfg - eth -- http://mail.python.org/mailman/listinfo/python-list
Re: read/ edit line from stdin
It's a bit more complicated. The field has a default and a preassigned Value. The default is p.e. 'localhost' and the value is 'www.gentoo.org'. Then localhost is chosen if the value is erased to ''. But i want to make it easy to keep the preassigned value! So if nothing is typed 'www.gentoo.org' should be used. I just thought that extending the commandline input interface would be quite useful. I want a text field that can be edited like common GUI-TextFields on command line... mfg - eth James Stroud wrote: > Clemens Hepper wrote: >> Hello, >> for my project confux (http://confux.sourceforge.net) I want to read >> a line from stdin. >> But I don't want the user to type a new line. I want so display a >> value which the user can edit. >> >> For example I want to ask the user for a hostname and I print >> "localhost", the user modified it to "localserver" and I read it >> after . >> >> What is the fastest way to realize that? I do NOT want to use curses >> (yet) ;-). >> >> mfg >> - eth > > Why don't you just make "localhost" the default and have the user enter > the complete name if they want it different. Seems like this is the way > every CL program I've ever seen works. > -- http://mail.python.org/mailman/listinfo/python-list
Re: Bitwise OR?
To look at the bit-structure i've implemented a little function: def bitstring(number, digits=32): """lsb-->msb""" result = "" for a in xrange(digits): if number & 1: result += '1' else: result += '0' number >>= 1 return result I wonder if there is something like sizeof() for int numbers. mfg - eth -- http://mail.python.org/mailman/listinfo/python-list
Re: Bitwise OR?
Hello, I've written a little (optimized) method to get a bit-string: def bitstringneg(number, digits=32): """optimized for negative numbers""" result = "" for a in xrange(digits): if number & 1: result += '1' else: result += '0' number >>= 1 return result def bitstringpos(number): """optimized for positive numbers""" result = "" while number: if number & 1: result += '1' else: result += '0' number >>= 1 return result def bitstring(number, digits=32): """lsb-->msb""" result = "" if number < 0: return bitstringneg(number, digits) else: return bitstringpos(number) BTW: Is there something like a sizeof() method for int numbers? mfg - eth -- http://mail.python.org/mailman/listinfo/python-list
Re: Bitwise OR?
Adam DePrince wrote:
>> BTW: Is there something like a sizeof() method for int numbers?
>
> import struct
> help( strict.calcsize )
Mh, that doesn't do what i want. I'd like to have something like:
def size(number):
return sizeof(number)
> Why one bit at a time?
Good question...
Here my new approach based on your idea:
_digits = { 0:"", 1:"1000", 2:"0100", 3:"1100",
4:"0010", 5:"1010", 6:"0110", 7:"1110",
8:"0001", 9:"1001", 0xa:"0101", 0xb:"1101",
0xc:"0011", 0xd:"1011", 0xe:"0111", 0xf:""}
def bitstring2(number):
"""lsb-->msb"""
rlist = list()
if number >= 0:
while number:
rlist.append( _digits[number & 0xF] )
number >>= 4
else:
while number != -1:
rlist.append( _digits[number & 0xF] )
number >>= 4
return ''.join(rlist)
This was faster for positive numbers. For negative numbers yours was
faster, but my version handles those numbers different.
Your version fails for Large numbers since hex( long ) returns
something like "0xFFFL" instead of "0xfff".
> Cheers - Adam
Cheers :)
- eth
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Re: Bitwise OR?
Okay... pythons build-in methods are quite fast. so is hex().
with about 64 kb memory i can write it with a 16 bit dictionary
where the dictionary generation itself is not yet optimized:
def genBitList(exp):
next = lambda now: [x+'0' for x in now]+[x+'1' for x in now]
result = [""]
for x in range(exp):
result = next(result)
return result
_digits = genBitList(16)
def bitstring2(number):
"""lsb-->msb"""
rlist = list()
if number >= 0:
while number:
rlist.append( _digits[number & 0x] )
number >>= 16
return ''.join(rlist).rstrip('0')
else:
while number != -1:
rlist.append( _digits[number & 0x] )
number >>= 16
return ''.join(rlist).rstrip('1')
this is quite fast and in lots of cases faster than the
hex()-version. however your method (with my inverses formatting) is
very fast, too and without so much memory expense:
_nibbles = {"0":"", "1":"0001", "2":"0010", "3":"0011",
"4":"0100", "5":"0101", "6":"0110", "7":"0111",
"8":"1000", "9":"1001", "a":"1010", "b":"1011",
"c":"1100", "d":"1101", "e":"1110", "f":"",
"l":"", "-":"", "x":""}
from string import maketrans, translate
_invert = maketrans('01', '10')
def bitstring3( number ):
if number > 0:
return ''.join( [_nibbles[d] for d in
hex( number ).lower()] ).lstrip( '0' )
else:
return translate(''.join( [_nibbles[d] for d in
hex( ~number ).lower()] ).lstrip( '0' ), _invert)
Benchmark:
for 0xa:
bitstring2: 0.61802315712
bitstring3: 0.91001200676
for 0x:
bitstring2: 0.561501026154
bitstring3: 1.11787199974
for 0x:
bitstring2: 1.2295820713
bitstring3: 1.61559510231
for 0x:
bitstring2: 1.90036797523
bitstring3: 2.2683339119
for -0x:
bitstring2: 2.81339716911
bitstring3: 2.74266886711
mfg
- eth
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Re: a problem to solve
Hi,
[EMAIL PROTECTED] wrote:
> That's one way to do it. I did it that way because I have the
> hex patterns memorized.
You should be able to generate your numbers like this:
number = int('001001000100100', 2)
mfg
- eth
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Re: Difference between 'is' and '=='
Roy Smith wrote:
> In article <[EMAIL PROTECTED]>,
> Joel Hedlund <[EMAIL PROTECTED]> wrote:
>
>> Which means that "is" comparisons in general will be faster than ==
>> comparisons.
>
> I thought that == automatically compared identify before trying to compare
> the values. Or am I thinking of some special case, like strings?
Even for strings there is a performance difference:
>>> timeit.Timer("'a'=='a'").timeit()
0.26859784126281738
>>> timeit.Timer("'a' is 'a'").timeit()
0.21730494499206543
mfg
- eth
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Re: Difference between 'is' and '=='
Dan Sommers wrote:
> This does *not* also mean constants and such:
>
> Python 2.4.2 (#1, Feb 22 2006, 08:02:53)
> [GCC 4.0.1 (Apple Computer, Inc. build 5247)] on darwin
> Type "help", "copyright", "credits" or "license" for more information.
> >>> a = 123456789
> >>> a == 123456789
> True
> >>> a is 123456789
> False
It's strange: python seem to cache constants from 0 to 99:
for x in xrange(1000):
if not eval("%d"%x) is eval("%d"%x):
print x
for me it printed 100-999.
- eth
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