random number generation

[Jah_Alarm]

hi,

I need to generate a binary array with a specified average proportion
of 1s (e.g. [1 0 0 0

0 1 0 0] has this proportion = 25%). In Matlab I run something like
random(m,n)<p where p is the value

between 0 and 1. I'm trying to use random.randint(0,2,size=[m,n]), but
I don't understand how to specify this proportion p.

thanks,

Alex

 

[Brian Blais]

hi,

I need to generate a binary array with a specified average proportion
of 1s (e.g. [1 0 0 0

0 1 0 0] has this proportion = 25%). In Matlab I run something like
random(m,n)<p where p is the value

between 0 and 1. I'm trying to use random.randint(0,2,size=[m,n]), but
I don't understand how to specify this proportion p.

if you're coming from matlab, then you should use the numpy package
(and you can post questions on the numpy list). In that case, you
can do:

from numpy import *
random.rand(5,7)<0.25

array([[False, True, True, False, False, True, False],
[False, False, False, False, True, False, False],
[ True, False, False, False, False, False, True],
[ True, False, True, False, False, False, False],
[False, False, False, False, False, False, False]], dtype=bool)


just like matlab.


bb

 

[Raymond Hettinger]

hi,

I need to generate a binary array with a specified average proportion
of 1s (e.g. [1 0 0 0

0 1 0 0] has this proportion = 25%). In Matlab I run something like
random(m,n)<p where p is the value

between 0 and 1. I'm trying to use random.randint(0,2,size=[m,n]), but
I don't understand how to specify this proportion p.

Try this:

from random import random
[1 if random() < 0.25 else 0 for i in range(20)]

[0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0]


Raymond