CODEWITHSUNDEEP
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Gergely Szarka
Gergely Szarka

Reputation: 95

calling matrix elements in a for loop in R

I would like to do something like so:

I have many matrices that look as follows:

head(cluster1,n=10)
      beg end      IBI len     durn  mean.isis SI
 [1,]   6   8       NA   3 0.109883 0.05494150  1
 [2,]  10  22 0.363067  13 0.350182 0.02918183  1
 [3,]  27  30 0.589205   4 0.128999 0.04299967  1
 [4,]  31  36 0.292974   6 0.048144 0.00962880  1
 [5,]  37  44 0.182525   8 0.227413 0.03248757  1
 [6,]  45  47 0.130840   3 0.063720 0.03186000  1
 [7,]  48  56 0.413761   9 0.182949 0.02286862  1
 [8,]  59  65 0.475499   7 0.192862 0.03214367  1
 [9,]  67  69 0.208579   3 0.027613 0.01380650  1
[10,]  70  74 0.116538   5 0.295098 0.07377450  1

head(cluster2,n=10)
      beg end       IBI len     durn   mean.isis SI
 [1,]   1   4        NA   4 0.011045 0.003681667  1
 [2,]  37  41 24.749159   5 0.037666 0.009416500  1
 [3,]  47  49  4.622307   3 0.008638 0.004319000  1
 [4,]  59  61  6.767432   3 0.008638 0.004319000  1
 [5,]  64  67  3.499121   4 0.012178 0.004059333  1
 [6,]  83  85  7.063805   3 0.007504 0.003752000  1
 [7,]  89  91  2.827788   3 0.015576 0.007788000  1
 [8,]  92  94  1.628137   3 0.007930 0.003965000  1
 [9,]  95  97  0.576744   3 0.008638 0.004319000  1
[10,] 103 105 10.000201   3 0.009204 0.004602000  1

I would like to create a for loop where I create a list of the the mean values of each of the matrix's 5th row values. 

mean(cluster1[,5])
[1] 0.2731692
mean(cluster2[,5])
[1] 0.01214404

It would give a result like so :

means(0.2731692,0.01214404)

What I tried to do:

means=''
for(i in 1:100){names.append(mean(str('cluster'+i)[,5]))}

This seems to not work as I hoped in R.

Any help is greatly appreciated!

Thanks

Upvotes: 0

Views: 59

Answers (3)

ThomasIsCoding
ThomasIsCoding

Reputation: 101335

Another base R option with mget, similar to the solution @Ronak Shah

sapply(lapply(mget(ls(pattern = "cluster")),`[[`,5),mean)

Upvotes: 1

Ronak Shah
Ronak Shah

Reputation: 388982

You can use mget to get all matrices in a list and then get mean of 5th column. 

sapply(mget(paste0('cluster', 1:2)), function(x) mean(x[, 5]))

Replace 2 in 1:2 with number cluster matrices that you have.

Upvotes: 2

yarnabrina
yarnabrina

Reputation: 1666

Try something like this:

means <- numeric(length = 100)

for (i in seq_len(length.out = 100))
{
    means[i] <- mean(x = get(x = paste0("cluster", i))[, 5])
}

This will return a vector in this format: c(0.2731692,0.01214404, ...). If you want as a space separated string, do this:

paste0(means, collapse=" ")

Hope this helps.

Upvotes: 3

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