从列表中随机选择 50 个项目写入文件 [英] Select 50 items from list at random to write to file
问题描述
到目前为止,我已经弄清楚了如何导入文件、创建新文件和随机化列表.
So far I have figured out how to import the file, create new files, and randomize the list.
我无法从列表中随机选择 50 个项目写入文件?
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+'
')
所以如果总随机化文件是
So if the total randomization file was
example:
random_total = ['9','2','3','1','5','6','8','7','0','4']
我想要 3 个文件 (out_file1|2|3),其中第一个随机集为 3,第二个随机集为 3,第三个随机集为 3(对于此示例,但我要创建的文件应该有 50)
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']
所以不会包含最后的4",这很好.
So the last '4' will not be included which is fine.
如何从随机化的列表中选择 50 个?
How can I select 50 from the list that I randomized ?
更好的是,我如何从原始列表中随机选择 50 个?
推荐答案
如果列表是随机排列的,你可以只取前50个.
If the list is in random order, you can just take the first 50.
否则,使用
import random
random.sample(the_list, 50)
random.sample
帮助文本:
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)
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