sample

问题 I want to draw a random sample from my dataset, using different proportions for each value of a factor variable, as well as using weights stored in some other column. dplyr solution in pipes will be preferred as it can be inserted easily in long code. Let's take the example of iris dataset. Species column is divided into three values 50 rows each. Let's also assume the sample weights are stored in column Sepal.Length . If I have to sample equal proportions (or equal rows) per species, the

问题 I want to draw a random sample from my dataset, using different proportions for each value of a factor variable, as well as using weights stored in some other column. dplyr solution in pipes will be preferred as it can be inserted easily in long code. Let's take the example of iris dataset. Species column is divided into three values 50 rows each. Let's also assume the sample weights are stored in column Sepal.Length . If I have to sample equal proportions (or equal rows) per species, the

问题 I want to draw a random sample from my dataset, using different proportions for each value of a factor variable, as well as using weights stored in some other column. dplyr solution in pipes will be preferred as it can be inserted easily in long code. Let's take the example of iris dataset. Species column is divided into three values 50 rows each. Let's also assume the sample weights are stored in column Sepal.Length . If I have to sample equal proportions (or equal rows) per species, the

来源： https://stackoverflow.com/questions/64445678/irregular-sampling-from-data

来源： https://stackoverflow.com/questions/55042334/pandas-sample-with-weights

来源： https://stackoverflow.com/questions/55042334/pandas-sample-with-weights

问题 I have a simple question regarding the sample function in R. I'm randomly sampling from 0s and 1s and summing them together, from an input vector of length 5, which designates the number of trials to run and sets the seed to generate reproducible random numbers. Seed works as expected, but I get different matrices of random numbers depending on what I put in the prob statement. In this case I assumed prob=NULL should be the same as prob=c(0.5,0.5). Why isn't it? vn<-c(12, 44, 9, 17, 28) > do

问题 i'm a newbie in Mongo and Cosmos DB. I'm trying to get some random values from one collection with the following aggregation query, but it delivers repeatedly same result: db.jokes.aggregate( [ { $sample: { size: 1 } } ] ) Operation consumed 2.39 RUs { "_id" : ObjectId("5b1526501e39b24ccc50d369"), "joke" : "Giraffes are born or created when Chuck Norris uppercuts a Horse!", "language" : "en" } db.jokes.aggregate( [ { $sample: { size: 1 } } ] ) Operation consumed 2.39 RUs { "_id" : ObjectId(

问题 I'm still learning R and have been given the task of grouping a long list of students into groups of four based on another variable. I have loaded the data into R as a data frame. How do I sample entire rows without replacement, one from each of 4 levels of a variable and have R output the data into a spreadsheet? So far I have been tinkering with a for loop and the sample function but I'm quickly getting over my head. Any suggestions? Here is sample of what I'm attempting to do. Given: Last

问题 I'm still learning R and have been given the task of grouping a long list of students into groups of four based on another variable. I have loaded the data into R as a data frame. How do I sample entire rows without replacement, one from each of 4 levels of a variable and have R output the data into a spreadsheet? So far I have been tinkering with a for loop and the sample function but I'm quickly getting over my head. Any suggestions? Here is sample of what I'm attempting to do. Given: Last