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rloopssapply

How to iterate over columns with Sapply for Pearson coefficient


[i] indicates where I have to iterate pearsons coefficient over the columns and how to convert this into a dataframe attached onto a variable?

Code example:

*INSTEAD OF DOING THIS*
F.ReedBunting.pear<- cor.test(W_farmland_mean$Years,W_farmland_mean$ReedBunting,method='pearson')
F.Whitethroat.pear<- cor.test(W_farmland_mean$Years,W_farmland_mean$Whitethroat,method='pearson')
F.Rook.pear<- cor.test(W_farmland_mean$Years,W_farmland_mean$Rook,method='pearson')
.
.
.
*HOW CAN IT BE DONE QUICKLY WITH THIS*
workspaceone <- sapply(W_farmland_mean, function(x){
    cor.test(W_farmland_mean$Years, W_farmland_mean[, 1[i]], method = 'pearson')
})


Solution

  • I think you should try:

    result_cor <- apply(W_farmland_mean,2,function(x){cor.test(W_farmland_mean$Years,x, method = 'pearson')$estimate})
    

    It will extract the Pearson coefficient of the comparison of each columns with the column years of your dataset.

    Example With the mtcars dataset:

    df <- mtcars[c(1:10),]
    
    > df
                       mpg cyl  disp  hp drat    wt  qsec vs am gear carb
    Mazda RX4         21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
    Mazda RX4 Wag     21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
    Datsun 710        22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
    Hornet 4 Drive    21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
    Hornet Sportabout 18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
    Valiant           18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
    Duster 360        14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
    Merc 240D         24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
    Merc 230          22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
    Merc 280          19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
    

    And if we apply the function:

    result_cor = apply(df,2, function(x){cor.test(x,df$mpg,method ='pearson')$estimate})
    

    And you get the following output:

    > result_cor
           mpg        cyl       disp         hp       drat         wt       qsec 
     1.0000000 -0.8614165 -0.7739868 -0.8937223  0.5413585 -0.5991894  0.5494131 
            vs         am       gear       carb 
     0.4796102  0.2919683  0.6646449 -0.3711956