# [R] sapply function and poisson distribution

Pete Brecknock Peter.Brecknock at bp.com
Mon Jan 5 00:21:35 CET 2015

```dimnik wrote
> thank you for your answer.Yes,that sounds right.I thought the same thing
> but the problem is how can i generalize the command for every vector of
> numbers not only for the specific example?not only for c(1,2),c(0.1,0.8).
>
> 2015-01-04 0:45 GMT+00:00 Pete Brecknock [via R] <

> ml-node+s789695n4701358h57 at .nabble

>>:
>
>>  dimnik wrote
>> i want to find  a function that takes in two vectors of numbers that have
>> the same
>> length.The output should be a list of vectors, where each vector is a
>> sequence of
>> randomly generated Poisson variables where the number of samples in each
>> vector is determined by the entries in the first input vector and the
>> lambdas come
>> from the entries in the second input vector. For example, :If the inputs
>> are c(1,2) and c(0.1,0.8) the output will be a list of twovectors where
>> the
>> first vectorhas a single sample from Poisson(0.1) and the second vector
>> has
>> two samples from Poisson(0.8).How can i do all that kind of stuff using
>> sapply function?
>>
>> How about using mapply, the multivariate version of sapply?
>>
>> Based on your example ...
>>
>> mapply(function(x,y) rpois(x,y), c(1,2),c(0.1,0.8))
>>
>> HTH
>>
>> Pete
>>
>> ------------------------------
>> below:
>>
>> http://r.789695.n4.nabble.com/sapply-function-and-poisson-distribution-tp4701353p4701358.html
>> <http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=4701353&code=dmFnZWxpc2d1ZEBnbWFpbC5jb218NDcwMTM1M3wtMTg5MDAyODgzMA==>
>> .
>> NAML
>>

Not sure how you intend to specify the input vectors for n and lambda

One way would be as below - you can amend the 2 vectors with the values of

n <- c(1,2,3,4,5)
lambda <- c(0.1,0.8,1.2,2.2,4.2)

mapply(function(x,y) rpois(x,y), n, lambda)

HTH

Pete

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