Binomial Distribution

The binomial distribution is one of discrete probability distribution　of the number of success in a sequence of statistically independent bernoulli trail.
I've just tried to created graph of binomial distribution with python. Hence it's somewhat of memo of that:)

Prepare the calss of bernoulli trial

At first, I created python class of bernoulli trial which return probability of bernoulli trial with parameter n,k,p. Following is what I implemented.

	import scipy.misc as scm
	def bernoulli_trial_calc(n,k,p):
	"""
	Parameter
	----------------
	n : number of statistically independent Bernoulli traial
	k : the number of success
	p : probability of success
	Retrun
	----------------
	Probability of this bernoulli traial
	"""
	return scm.comb(n,k) * ((p) **k) * ((1-p)**(n-k))
	class bernoulli_trial:
	"""
	class of beroulli_traial requeires two parameter n,p for initilization.
	"""
	def __init__(self,n,p):
	"""
	Parameter:
	----------------
	n : number of statistically indepent Bernoulli trial
	p : probabillity of success
	"""
	self.n = n
	self.p = p
	def calc(self,klist):
	"""
	Parameter:
	----------------
	k : list of number of success
	"""
	prob_list = []
	for suc_num in klist:
	prob_list.append(bernoulli_trial_calc(self.n,suc_num,self.p))
	return prob_list
	if __name__ == '__main__':
	n = 3
	p = 1/3
	ber_trial = bernoulli_trial(n,p)
	klist = [0,1,2,3]
	probability_list = ber_trial.calc(klist)
	print(probability_list)

view raw bernoulli_traial.py hosted with ❤ by GitHub

Create graph of binomial distribution with various probability of success

Following is the graph with various probability of success in bernoulli trial.

From the result bellow, the vertex of probability distribution seems to be determined by probability of success in bernoulli trial.

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view raw BinomialDistrution.ipynb hosted with ❤ by GitHub

Create graph of binomial distribution with various the number of bernoulli traial

Following is the graph with various number of bernoulli trial.

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view raw BinomialDistribution2.ipynb hosted with ❤ by GitHub

How to use '@' option in zip command ??

You can specify files to be zipped from standard input by using '@' option as following.

    
$ touch {a,b,c,d}
$ ls
a b c d
$ ls -ltrh
total 0
-rw-r--r--  1 user1  staff     0B  2  1 16:44 d
-rw-r--r--  1 user1  staff     0B  2  1 16:44 c
-rw-r--r--  1 user1  staff     0B  2  1 16:44 b
-rw-r--r--  1 user1  staff     0B  2  1 16:44 a
$ vi filelist
$ 
$ cat ./filelist 
a
b
c
d
$ cat ./filelist | zip -@ ./test.zip
  adding: a (stored 0%)
  adding: b (stored 0%)
  adding: c (stored 0%)
  adding: d (stored 0%)
$ ls
a        b        c        d        filelist test.zip
$ mkdir result
$ unzip ./test.zip -d $_
Archive:  ./test.zip
 extracting: ./result/a              
 extracting: ./result/b              
 extracting: ./result/c              
 extracting: ./result/d              
$ ls ./result/
a b c d
$ 
    

In case that there are several files in a directory, and partially you wanna zip, you can specify which file you wanna zip thorough file-list or standard input.