seeding

I want to randomly select n rows from my data set using the sample() function in R . I was getting different outputs each time and hence used set.seed() function to get the same output. I know that each integer in the set.seed() will give me a unique output and the output will be the same if set the same seed. But I'm not able to make out what that integer that is passed as a parameter to the set.seed() function means. Is it just an index that goes into the random generator algorithm or does it mean some part of the data from where you start sampling? For example, what does the 2 in set.seed(2

Rake db:seed populates your db with default database values for an app right? So what if you already have a seed and you need to add to it(you add a new feature that requires the seed). In my experience, when I ran rake db:seed again, it added the existing content already so existing content became double. What I need is to add some seeds and when ran, it should just add the newest ones, and ignore the existing seeds. How do I go about with this? (the dirty, noob way I usually do it is to truncate my whole db then run seed again, but that's not very smart to do in production, right?) I do

I'd like to set seeds in R only locally (inside functions), but it seems that R sets seeds not only locally, but also globally. Here's a simple example of what I'm trying (not) to do. myfunction <- function () { set.seed(2) } # now, whenever I run the two commands below I'll get the same answer myfunction() runif(1) So, my questions are: why does R set the seed globally and not only inside my function? And how I can make R to set the seed only inside my function? Something like this does it for me: myfunction <- function () { old <- .Random.seed set.seed(2) res <- runif(1) .Random.seed <<- old

When I run rake db:seed in my Rails app, I'm getting this error: invalid byte sequence in US-ASCII (Argument Error) I just added science_majors and down to my seed file, and now when I run rake db:seed it gives me this error: invalid byte sequence error Why is this, and how can I fix it? part of seeds.rb @college = College.find_or_create_by_name!('University of Pittsburgh') if @college.update_attributes( url: 'university-of-pittsburgh', public: 'Public', years: '4-year', category: 'National University', calendar: 'Semester', location: 'Pittsburgh, PA', setting: 'Large City (250-500k)',

Does SQLite support seeding the RANDOM() function the same way MySQL does with RAND() ? $query = "SELECT * FROM table ORDER BY RAND(" . date('Ymd') . ") LIMIT 1;"; From the MySQL Manual about RAND(N) : If a constant integer argument N is specified, it is used as the seed value, which produces a repeatable sequence of column values. In the following example, note that the sequences of values produced by RAND(3) is the same both places where it occurs. If not, is there any way to archive the same effect using only one query? If you need a pseudo-random order, you can do something like this (PHP)

I have created a new clean asp.net 5 project (rc1-final). Using Identity Authentication I just have the ApplicationDbContext.cs with the following code: public class ApplicationDbContext : IdentityDbContext<ApplicationUser> { protected override void OnModelCreating(ModelBuilder builder) { // On event model creating base.OnModelCreating(builder); } } Please note ApplicationDbContext use IdentityDbContext and not DbContext. There is any IdentityConfig.cs. Where i need to put the classic protected override void Seed to create role and user if it does not exist? My way of doing this is to create a