0

The "do" command from the mosaic package nicely returns a data frame by default.

require(mosaic)
require(Sleuth3)


nulldist1 <- do(10)*t.test(Incidents~shuffle(Launch),
                           data=case0401,var.equal=TRUE)$statistic
class(nulldist1)

Now, I'd like to use the replicate command to do the same thing. Is there an argument that one can set in the replicate command that will force it to return a data frame? I tried simplify="data.frame" but that didn't work.

nulldist2 <- replicate(10,{
  t.test(Incidents~shuffle(Launch),
         data=case0401,var.equal=TRUE)$statistic
})
class(nulldist2)

Any thoughts?

4

2 回答 2

1 
data.frame(result = replicate(10,t.test(rnorm(100),rnorm(100))$statistic))
于 2014-05-29T21:41:04.850 回答
0

If you read ?replicate you'll notice that there is no simplify = "data.frame" option and hence it is no surprise that that didn't work.

As replicate() returns an array, and assuming the result is a 2-d array, just use as.data.frame() on the object nulldist2

nulldist2 <- as.data.frame(nulldist2)

Here's an example:

> arr <- replicate(10, quantile(rnorm(1000)))
> arr
           [,1]        [,2]        [,3]         [,4]        [,5]        [,6]
0%   -3.3574313 -3.09705035 -2.85009578 -3.140181733 -2.94235439 -3.24334919
25%  -0.6610031 -0.68506227 -0.66891111 -0.681785814 -0.66985211 -0.60439317
50%   0.0576617  0.05899849 -0.01235571  0.007168725  0.07139977  0.07511633
75%   0.7584004  0.67879534  0.69335820  0.659121437  0.72854080  0.76506110
100%  3.0837762  2.89445426  3.23701556  3.084539130  3.06543839  3.07470137
            [,7]        [,8]        [,9]       [,10]
0%   -2.78486552 -3.44680297 -3.27408224 -2.87007187
25%  -0.69813726 -0.62989631 -0.68281294 -0.61806994
50%  -0.02589364  0.03913355 -0.04370316  0.05563488
75%   0.66519651  0.74677634  0.64744094  0.74664823
100%  3.13266873  4.64939039  2.68895458  3.16797447
> df <- as.data.frame(t(arr))
> df
          0%        25%          50%       75%     100%
1  -3.357431 -0.6610031  0.057661700 0.7584004 3.083776
2  -3.097050 -0.6850623  0.058998490 0.6787953 2.894454
3  -2.850096 -0.6689111 -0.012355714 0.6933582 3.237016
4  -3.140182 -0.6817858  0.007168725 0.6591214 3.084539
5  -2.942354 -0.6698521  0.071399769 0.7285408 3.065438
6  -3.243349 -0.6043932  0.075116334 0.7650611 3.074701
7  -2.784866 -0.6981373 -0.025893640 0.6651965 3.132669
8  -3.446803 -0.6298963  0.039133547 0.7467763 4.649390
9  -3.274082 -0.6828129 -0.043703156 0.6474409 2.688955
10 -2.870072 -0.6180699  0.055634885 0.7466482 3.167974
> class(df)
[1] "data.frame"
于 2014-05-29T21:41:49.857 回答