Python 从列表中随机选择 50 个项目写入文件
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Select 50 items from list at random to write to file
提问by O.rka
So far I have figured out how to import the file, create new files, and randomize the list.
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。
I'm having trouble selecting only 50 items from the list randomly to write to a file?
我无法从列表中随机选择 50 个项目写入文件？
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
所以如果总随机化文件是
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)
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 个）
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.
所以最后的“4”不会被包括在内，这很好。
How can I select 50 from the list that I randomized ?
如何从随机化的列表中选择 50 个？
Even better, how could I select 50 at random from the original list ?
更好的是，我怎么能从原始列表中随机选择 50 个？
采纳答案by John La Rooy
If the list is in random order, you can just take the first 50.
如果列表是随机排列的，您可以只取前 50 个。
Otherwise, use
否则，使用
import random
random.sample(the_list, 50)
random.samplehelp text:
random.sample帮助文字：
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)
回答by Moeen MH
I think random.choice()is a better option.
我认为random.choice()是更好的选择。
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
该函数从列表中返回一个由 3 个随机选择的值组成的数组
回答by Mani
One easy way to select random items is to shuffle then slice.
选择随机项目的一种简单方法是先洗牌，然后再切片。
import random
a = [1,2,3,4,5,6,7,8,9]
random.shuffle(a)
print a[:4] # prints 4 random variables
回答by AlketCecaj
Say your list has 100 elements and you want to pick 50 of them in a random way. Here are the steps to follow:
假设您的列表有 100 个元素，并且您想以随机方式选择其中的 50 个。以下是要遵循的步骤：
- Import the libraries
- Create the seed for random number generator, I have put it at 2
- Prepare a list of numbers from which to pick up in a random way
- Make the random choices from the numbers list
- 导入库
- 创建随机数生成器的种子，我把它放在 2
- 准备一个数字列表，从中随机抽取
- 从数字列表中随机选择
Code:
代码：
from random import seed
from random import choice
seed(2)
numbers = [i for i in range(100)]
print(numbers)
for _ in range(50):
selection = choice(numbers)
print(selection)
