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I am trying to create a correlation matrix plot that only shows the significant correlations (p < .05) among a very large dataset. The point is to avoid doing individual correlations with each possible combination of 2 variables, which would take a lot of time.

Here is the code I'm using:

df_cor <- mtcars %>% mutate_if(is.character, as.factor)
df_cor <- df_cor %>% mutate_if(is.factor, as.numeric)

even using the mtcars dataframe and it produces the following error:

Error in UseMethod("tbl_vars") : no applicable method for 'tbl_vars' applied to an object of class "function"

I found this related question, but it seems to be a problem of not passing an actual dataframe instead of something else.

SurpriseDog
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  • Do you actually have a data frame called `data`? It works fine if you replace `data` with `mtcars`. I think you _are_ having the same problem, since R thinks you mean the _function_ `data`, which it would only do if there isn't a dataframe called `data` – Allan Cameron Mar 21 '22 at 19:54
  • I've tried running directly from mtcars and it doesn't work. – SurpriseDog Mar 21 '22 at 19:57
  • That doesn't seem right (see my reprex below). This code should work without problems. What versions of R and `dplyr` are you running? `Have you tried starting a new session? – Allan Cameron Mar 21 '22 at 20:05
  • @AllanCameron Thanks, updating RStudio solved everything. – SurpriseDog Mar 21 '22 at 20:47

2 Answers2

2

Try this:

df_cor <- data %>% 
  mutate(across(where(is.character), as.factor))
 
df_cor <- df_cor %>% 
  mutate(across(where(is.factor), as.numeric))
TarJae
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    This is the way. `mutate_if()` has been superseded by using the `across()` function within `mutate()`. Look at `?across` or `vignette("colwise")` to learn how to use this new functionality. – Ben Norris Mar 21 '22 at 20:07
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    This _is_ the paradigmatic way of running the code, but the code in the OP should also run. Have you tried it on your machine TarJae? – Allan Cameron Mar 21 '22 at 20:09
  • I think the problem is that in the mtcars dataset there is no character column?! So therefore I can't test df_cor. The code runs but I can't verify because `glimpse(mtcars) glimpse(df_cor)` is the same with no change in the data class. – TarJae Mar 21 '22 at 20:12
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    @TarJae if you try it with iris or converting some mtcars cols to character it should work – Allan Cameron Mar 21 '22 at 20:59
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    You are right and I fully agree. But we should use the newest syntax as 'superseded' means it will work but there is a better alternative! But I see it is not issue here. The issue is why the OP gets the error. – TarJae Mar 21 '22 at 21:09
2

This is more of a demonstration than an answer, but there is nothing wrong with the code in the question; it should not cause the reported error in the latest versions of R and dplyr.

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union

df_cor <- mtcars %>% mutate_if(is.character, as.factor)
df_cor <- df_cor %>% mutate_if(is.factor, as.numeric)
df_cor
#>                      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
#> Merc 280C           17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
#> Merc 450SE          16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
#> Merc 450SL          17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
#> Merc 450SLC         15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
#> Cadillac Fleetwood  10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
#> Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
#> Chrysler Imperial   14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
#> Fiat 128            32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
#> Honda Civic         30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
#> Toyota Corolla      33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
#> Toyota Corona       21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
#> Dodge Challenger    15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
#> AMC Javelin         15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
#> Camaro Z28          13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
#> Pontiac Firebird    19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
#> Fiat X1-9           27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
#> Porsche 914-2       26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
#> Lotus Europa        30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
#> Ford Pantera L      15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
#> Ferrari Dino        19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
#> Maserati Bora       15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
#> Volvo 142E          21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

Created on 2022-03-21 by the reprex package (v2.0.1)

Allan Cameron
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