Select 50 items from list at random to write to file
So far I have figured out how to import the file, create new files, and randomize the list.
I'm having trouble selecting only 50 items from the list randomly to write to a file?
def randomizer(input,output1='random_1.txt',output2='random_2.txt',output3='random_3.txt',output4='random_total.txt'):
#Input file
query=open(input,'r').read().split()
dir,file=os.path.split(input)
temp1 = os.path.join(dir,output1)
temp2 = os.path.join(dir,output2)
temp3 = os.path.join(dir,output3)
temp4 = os.path.join(dir,output4)
out_file4=open(temp4,'w')
random.shuffle(query)
for item in query:
out_file4.write(item+'\n')
So if the total randomization file was
example:
random_total = ['9','2','3','1','5','6','8','7','0','4']
I would want 3 files (out_file1|2|3) with the first random set of 3, second random set of 3, and third random set of 3 (for this example, but the one I want to create should have 50)
random_1 = ['9','2','3']
random_2 = ['1','5','6']
random_3 = ['8','7','0']
So the last '4' will not be included which is fine.
How can I select 50 from the list that I randomized ?
Even better, how could I select 50 at random from the original list ?
If the list is in random order, you can just take the first 50.
Otherwise, use
import random
random.sample(the_list, 50)
random.sample
help text:
sample(self, population, k) method of random.Random instance
Chooses k unique random elements from a population sequence.
Returns a new list containing elements from the population while
leaving the original population unchanged. The resulting list is
in selection order so that all sub-slices will also be valid random
samples. This allows raffle winners (the sample) to be partitioned
into grand prize and second place winners (the subslices).
Members of the population need not be hashable or unique. If the
population contains repeats, then each occurrence is a possible
selection in the sample.
To choose a sample in a range of integers, use xrange as an argument.
This is especially fast and space efficient for sampling from a
large population: sample(xrange(10000000), 60)
One easy way to select random items is to shuffle then slice.
import random
a = [1,2,3,4,5,6,7,8,9]
random.shuffle(a)
print a[:4] # prints 4 random variables
I think random.choice()
is a better option.
import numpy as np
mylist = [13,23,14,52,6,23]
np.random.choice(mylist, 3, replace=False)
the function returns an array of 3 randomly chosen values from the list
-
we have 3 samples ('orange','mango','apple'). Created series, should contain 7 elements & randomly selected from list.
random.choice
import random import numpy as np fruits = ['orange','mango','apple'] np.random.choice(fruits, 7, replace=True)
Output
array(['orange', 'mango', 'apple', 'orange', 'orange', 'mango', 'apple'], dtype='<U6')
-
Random selection from list (less than 3 values)
random.sample
import random random.sample(fruits, 3)