Plot correlation between variables by group with possible facet in R

Reubebe · February 17, 2022, 8:01am

I want to do one of two things:

either plot the correlation between a pair of variables (Eye1 and Hand 1) and facet/ separate by groups (1 and 2).
Or get correlation pairs (Eye1,Hand1,Eye2,Hand2,Eye3,Hand3) and facet/ separate by groups (1 and 2)

data10 <- structure(list(Group = c(1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2), 
    Eye1 = c(5, 5, 8, 5, 7, 6, 6, 8, 5, 6, 7, 5), Hand1 = c(6, 
    6, 7, 6, 6, 7, 7, 6, 7, 6, 6, 7), Eye2 = c(5, 5, 8, 5, 7, 
    5, 6, 8, 5, 6, 7, 5), Hand2 = c(6, 6, 2, 6, 6, 3, 7, 6, 4, 
    6, 6, 7), Eye3 = c(2, 5, 8, 3, 7, 6, 6, 5, 5, 2, 7, 5), Hand3 = c(6, 
    6, 7, 6, 6, 7, 7, 6, 7, 6, 6, 7)), class = c("spec_tbl_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -12L), spec = structure(list(
    cols = list(Group = structure(list(), class = c("collector_double", 
    "collector")), Eye1 = structure(list(), class = c("collector_double", 
    "collector")), Hand1 = structure(list(), class = c("collector_double", 
    "collector")), Eye2 = structure(list(), class = c("collector_double", 
    "collector")), Hand2 = structure(list(), class = c("collector_double", 
    "collector")), Eye3 = structure(list(), class = c("collector_double", 
    "collector")), Hand3 = structure(list(), class = c("collector_double", 
    "collector"))), default = structure(list(), class = c("collector_guess", 
    "collector")), skip = 1), class = "col_spec"))

library(ggplot)

p <- ggplot(data10, aes(Eye1, Hand1)) + geom_point()

cors <- ddply(data10, c("1", "2"), summarise, cor = round(cor(Eye1, Hand1), 2))

p + facet_grid(1 ~ 2) +
  geom_text(data=data10, aes(label=paste("r=", cor, sep="")), x=30, y=4)

FJCC · February 17, 2022, 4:13pm

Are you looking for something like this?

data10 <- structure(list(Group = c(1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2), 
                         Eye1 = c(5, 5, 8, 5, 7, 6, 6, 8, 5, 6, 7, 5), 
                         Hand1 = c(6, 6, 7, 6, 6, 7, 7, 6, 7, 6, 6, 7), 
                         Eye2 = c(5, 5, 8, 5, 7, 5, 6, 8, 5, 6, 7, 5), 
                         Hand2 = c(6, 6, 2, 6, 6, 3, 7, 6, 4, 6, 6, 7), 
                         Eye3 = c(2, 5, 8, 3, 7, 6, 6, 5, 5, 2, 7, 5), 
                         Hand3 = c(6, 6, 7, 6, 6, 7, 7, 6, 7, 6, 6, 7)), 
                    class = c("spec_tbl_df", 
                              "tbl_df", "tbl", "data.frame"), row.names = c(NA, -12L), 
                    spec = structure(list(cols = list(Group = structure(list(), class = c("collector_double", "collector")), 
                                                      Eye1 = structure(list(), class = c("collector_double","collector")), 
                                                      Hand1 = structure(list(), class = c("collector_double", "collector")), 
                                                      Eye2 = structure(list(), class = c("collector_double", "collector")), 
                                                      Hand2 = structure(list(), class = c("collector_double","collector")), 
                                                      Eye3 = structure(list(), class = c("collector_double", "collector")), 
                                                      Hand3 = structure(list(), class = c("collector_double", "collector"))), 
                                          default = structure(list(), class = c("collector_guess", "collector")), skip = 1), class = "col_spec"))
library(dplyr)
library(tidyr)
library(ggplot2)

dataLong <- data10 |> pivot_longer(cols = -Group,
                                   names_to=c(".value","Index"),
                                   names_pattern = "(Eye|Hand)(\\d)") |> 
  mutate(Group=paste0("Grp_",Group))
  
dataLong
#> # A tibble: 36 x 4
#>    Group Index   Eye  Hand
#>    <chr> <chr> <dbl> <dbl>
#>  1 Grp_1 1         5     6
#>  2 Grp_1 2         5     6
#>  3 Grp_1 3         2     6
#>  4 Grp_1 1         5     6
#>  5 Grp_1 2         5     6
#>  6 Grp_1 3         5     6
#>  7 Grp_1 1         8     7
#>  8 Grp_1 2         8     2
#>  9 Grp_1 3         8     7
#> 10 Grp_1 1         5     6
#> # ... with 26 more rows
Cors <- dataLong |> group_by(Group,Index) |> summarize(Cor=round(cor(Eye,Hand),3))
#> `summarise()` has grouped output by 'Group'. You can override using the `.groups` argument.
Cors
#> # A tibble: 6 x 3
#> # Groups:   Group [2]
#>   Group Index    Cor
#>   <chr> <chr>  <dbl>
#> 1 Grp_1 1      0.612
#> 2 Grp_1 2     -0.506
#> 3 Grp_1 3      0.613
#> 4 Grp_2 1     -0.781
#> 5 Grp_2 2      0.156
#> 6 Grp_2 3      0.218
ggplot(dataLong,aes(x=Hand,y=Eye))+geom_point()+
  facet_grid(Index~Group)+
  geom_text(aes(x=4,y=4,label=paste("r=",Cor)),data=Cors)

^{Created on 2022-02-17 by the reprex package (v2.0.1)}

Reubebe · February 17, 2022, 7:25pm

I am using a longer data set but it seems to be giving me just a single value for the correlation

data10 <- structure(list(Group = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 
2, 2, 2, 2, 2, 2), Eye1 = c(0.1625, 0.6145, 0.1335, 0.083, 0.1165, 
0.2585, 0.2085, 0.549, 0.142, 0.1585, 0.1835, 0.2585, 0.1835, 
0.334, 0.1505, 0.166, 0.1085, 0.25, 0.1505, 0.452, 0.117, 0.183, 
0.1745, 0.3335, 0.158, 0.3, 0.071, 0.133, 0.15, 0.3085, 0.133, 
0.3415, 0.125, 0.25, 0.158, 0.3965, 0.158, 0.167, 0.1, 0.117, 
0.1745, 0.1335, 0.134, 0.25, 0.1335, 0.125, 0.1, 0.175, 0.1835, 
0.133, 0.1, 0.125, 0.167, 0.184, 0.1415, 0.4805, 0.1335, 0.1085, 
0.133, 0.133, 0.167, 0.1335, 0.116, 0.134, 0.1505, 0.1415, 0.092, 
0.367, 0.166, 0.1, 0.167, 0.15, 0.142, 0.2, 0.1505, 0.168, 0.116, 
0.2, 0.3585, 0.1835, 0.1165, 0.1585, 0.175, 0.258, 0.154, 0.167, 
0.167, 0.136, 0.1, 0.2085, 0.3445, 0.192, 0.116, 0.116, 0.166, 
0.2, 0.129, 0.2, 0.1165, 0.1165, 0.117, 0.242, 0.327, 0.192, 
0.1, 0.167, 0.154, 0.242, 0.125, 0.133, 0.1495, 0.1165, 0.117, 
0.117, 0.0915, 0.1585, 0.117, 0.108, 0.117, 0.1165, 0.1715, 0.167, 
0.133, 0.116, 0.133, 0.133, 0.083, 0.1865, 0.133, 0.1165, 0.117, 
0.116, 0.1, 0.134, 0.1165, 0.117, 0.134, 0.125, 0.083, 0.225, 
0.108, 0.125, 0.117, 0.1165), Hand1 = c(0.369, 0.75, 0.35, 0.35, 
0.2165, 0.3835, 0.517, 0.433, 0.283, 0.367, 0.475, 0.4, 0.4125, 
0.4005, 0.35, 0.4, 0.2165, 0.392, 0.5085, 0.433, 0.258, 0.3665, 
0.4165, 0.383, 0.329, 0.667, 0.3665, 0.3165, 0.275, 0.466, 0.6415, 
0.4585, 0.2835, 0.433, 0.433, 0.4245, 0.358, 0.4, 0.3, 0.367, 
0.3, 0.267, 0.434, 0.45, 0.519, 0.3335, 0.3, 0.742, 0.3335, 0.3, 
0.333, 0.325, 0.335, 0.3, 0.4165, 0.522, 0.3755, 0.3745, 0.275, 
0.4, 0.3, 0.35, 0.284, 0.4, 0.35, 0.325, 0.4335, 0.564, 0.466, 
0.3415, 0.333, 0.567, 0.3665, 0.2845, 0.3, 0.3995, 0.2585, 0.358, 
0.4415, 0.4, 0.2745, 0.366, 0.475, 0.558, 0.3195, 0.3495, 0.333, 
0.583, 0.267, 0.3335, 0.6475, 0.367, 0.283, 0.391, 0.467, 0.4835, 
0.354, 0.383, 0.3, 0.4, 0.25, 0.3165, 0.526, 0.392, 0.2745, 0.3745, 
0.508, 0.475, 0.329, 0.3075, 0.3, 0.3, 0.292, 0.283, 0.3165, 
0.2415, 0.3915, 0.3335, 0.3255, 0.333, 0.3835, 0.3, 0.3, 0.292, 
0.2665, 0.3, 0.342, 0.275, 0.4, 0.2655, 0.3085, 0.334, 0.341, 
0.267, 0.3195, 0.317, 0.283, 0.3165, 0.4, 0.25, 0.3415, 0.3165, 
0.316, 0.3335), Eye2 = c(0.152, 1.401, 1.111, 2.372, 0.2005, 
0.4805, 1.663, 1.97, 0.719, 1.3735, 1.283, 0.795, 0.1625, 1.406, 
1.0035, 2.323, 0.167, 0.2725, 1.453, 1.265, 0.343, 1.055, 1.199, 
0.3825, 0.923, 2.033, 0.9435, 1.76, 0.2335, 0.473, 2.543, 2.2415, 
0.7535, 1.691, 1.437, 1.2865, 0.314, 0.566, 0.2665, 0.166, 0.5945, 
0.514, 0.333, 0.498, 3.879, 0.309, 0.344, 2.2515, 0.4295, 0.366, 
0.333, 0.167, 0.167, 0.333, 0.333, 0.346, 3.161, 0.3, 0.434, 
0.383, 0.4, 1.035, 0.334, 0.15, 0.6835, 1.417, 1.99, 0.646, 4.727, 
0.89, 0.804, 1.695, 0.254, 0.445, 0.3665, 1.353, 0.1665, 0.2745, 
0.5535, 0.2985, 0.166, 1.127, 1.238, 1.068, 0.1805, 0.8915, 0.635, 
1.631, 0.2165, 0.252, 0.1825, 0.304, 0.1775, 1.005, 1.207, 0.6085, 
0.1765, 0.661, 0.4775, 1.431, 0.1835, 0.3365, 1.236, 0.324, 0.1585, 
1.425, 1.6555, 0.646, 0.2, 0.596, 0.267, 0.175, 0.272, 0.308, 
0.167, 0.167, 3.0555, 0.3, 0.1745, 0.3005, 0.167, 0.361, 0.267, 
0.183, 0.246, 0.166, 0.1925, 0.168, 2.668, 0.3315, 0.15, 0.167, 
0.2835, 0.367, 0.5105, 0.192, 0.15, 0.4185, 0.25, 0.215, 3.036, 
0.3085, 0.15, 0.254), Hand2 = c(1.4485, 2.3315, 1.8555, 2.788, 
0.9965, 1.133, 2.817, 3.1015, 1.3025, 2.401, 1.45, 1.5335, 1.25, 
1.483, 1.5815, 2.879, 1.0765, 1.198, 2.475, 3.027, 1.308, 1.69, 
1.6245, 1.609, 1.771, 2.406, 2.3945, 2.574, 1.0995, 1.274, 3.189, 
3.2325, 1.6815, 2.112, 1.992, 2.074, 1.555, 2.196, 1.476, 1.319, 
2.3245, 1.513, 2.13, 1.533, 4.0535, 1.393, 1.404, 2.479, 1.2575, 
1.627, 1.627, 1.2035, 1.972, 1.627, 2.0135, 1.723, 3.549, 1.3065, 
1.509, 1.896, 1.337, 1.9335, 1.7195, 1.614, 1.8595, 2.093, 2.756, 
1.784, 4.445, 1.954, 1.7855, 2.418, 1.73, 1.301, 1.437, 2.0635, 
0.85, 0.958, 1.903, 1.7835, 1.0625, 1.831, 1.581, 1.569, 1.479, 
1.427, 1.166, 2.1075, 0.812, 0.9445, 2.0145, 1.621, 0.954, 1.461, 
1.742, 1.6455, 1.74, 1.35, 1.365, 2.157, 0.786, 1.0795, 2.419, 
1.695, 0.979, 2.011, 2.128, 1.893, 1.2055, 1.6185, 0.999, 1.453, 
1.1085, 1.151, 1.3145, 1.1525, 3.35, 0.95, 1.0535, 1.376, 1.0295, 
1.237, 1.209, 1.0765, 0.99, 1.368, 1.0525, 1.293, 2.899, 0.8785, 
0.892, 0.946, 1.236, 2.03, 1.279, 1.583, 1.4125, 1.5555, 1.245, 
1.2275, 2.8515, 1.0295, 1.132, 1.2335), Eye3 = c(0.329, 2.3125, 
1.294, 2.554, 0.3085, 0.7555, 1.913, 2.336, 0.869, 1.6545, 1.45, 
1.2595, 0.3625, 1.811, 1.304, 2.656, 0.292, 0.5305, 1.537, 1.947, 
0.653, 1.424, 1.3655, 0.619, 1.08, 2.337, 1.0105, 1.947, 0.5005, 
0.7905, 2.626, 2.331, 0.862, 2.008, 1.554, 1.7715, 0.453, 0.666, 
0.422, 0.284, 0.753, 0.6645, 0.467, 0.767, 4.0125, 0.4515, 0.439, 
2.6085, 0.596, 0.5, 0.433, 0.3085, 0.35, 0.55, 0.4665, 0.785, 
3.2945, 0.41, 0.584, 0.516, 0.533, 1.1575, 0.4665, 0.3, 0.842, 
1.575, 2.3285, 1.03, 5.045, 0.9645, 0.999, 1.845, 0.408, 0.6785, 
0.5, 1.588, 0.2665, 0.425, 1.24, 0.5605, 0.2855, 1.2575, 1.356, 
1.4355, 0.31, 1.075, 0.901, 1.763, 0.3, 0.46, 1.11, 0.475, 0.3, 
1.1245, 1.374, 0.9005, 0.3015, 0.911, 0.7605, 1.584, 0.3085, 
0.573, 1.515, 0.541, 0.2505, 1.68, 1.8555, 1.165, 0.341, 0.7125, 
0.4505, 0.297, 0.422, 0.3835, 0.267, 0.334, 3.164, 0.384, 0.342, 
0.4165, 0.35, 0.494, 0.466, 0.275, 0.379, 0.317, 0.275, 0.45, 
2.818, 0.4465, 0.3, 0.3, 0.3795, 0.533, 0.6145, 0.276, 0.3825, 
0.5685, 0.35, 0.3985, 3.1365, 0.4335, 0.267, 0.359), Hand3 = c(1.8075, 
2.896, 2.222, 3.056, 1.23, 1.483, 3.3425, 3.4345, 1.5895, 2.801, 
1.965, 1.911, 1.658, 2.3415, 1.8805, 3.301, 1.2935, 1.588, 3.147, 
3.461, 1.508, 2.107, 2.041, 2.026, 2.096, 2.915, 2.8, 2.907, 
1.335, 1.7655, 3.894, 3.7165, 1.9735, 2.654, 2.309, 2.541, 1.947, 
2.596, 1.8, 1.636, 2.5915, 1.763, 2.48, 1.955, 4.6585, 1.7415, 
1.6775, 3.199, 1.628, 1.994, 1.998, 1.5895, 2.301, 1.903, 2.4555, 
2.1685, 3.928, 1.6565, 1.743, 2.296, 1.57, 2.3835, 1.9995, 1.984, 
2.693, 2.418, 3.2325, 2.348, 5.045, 2.304, 2.136, 3.051, 2.0245, 
1.5885, 1.687, 2.3985, 1.1, 1.381, 2.413, 2.1765, 1.335, 2.184, 
2.014, 2.2635, 1.743, 1.7055, 1.466, 2.54, 1.0605, 1.255, 2.588, 
2.021, 1.237, 1.871, 2.074, 2.179, 2.002, 1.752, 1.665, 2.612, 
1.04, 1.4045, 2.892, 2.1105, 1.254, 2.3935, 2.748, 2.4005, 1.522, 
1.976, 1.363, 1.7445, 1.392, 1.476, 1.6235, 1.414, 3.6665, 1.242, 
1.362, 1.718, 1.413, 1.704, 1.542, 1.3845, 1.2895, 1.585, 1.394, 
1.588, 3.203, 1.102, 1.225, 1.28, 1.5285, 2.297, 1.532, 1.883, 
1.679, 1.822, 1.645, 1.512, 3.245, 1.338, 1.465, 1.5585)), class = c("spec_tbl_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -144L), spec = structure(list(
    cols = list(Group = structure(list(), class = c("collector_double", 
    "collector")), Eye1 = structure(list(), class = c("collector_double", 
    "collector")), Hand1 = structure(list(), class = c("collector_double", 
    "collector")), Eye2 = structure(list(), class = c("collector_double", 
    "collector")), Hand2 = structure(list(), class = c("collector_double", 
    "collector")), Eye3 = structure(list(), class = c("collector_double", 
    "collector")), Hand3 = structure(list(), class = c("collector_double", 
    "collector"))), default = structure(list(), class = c("collector_guess", 
    "collector")), skip = 1), class = "col_spec"))

FJCC · February 17, 2022, 8:02pm

I used the larger data set you posted and got the following:

library(dplyr)
library(tidyr)
library(ggplot2)
dataLong <- data10 |> pivot_longer(cols = -Group,
                                    names_to=c(".value","Index"),
                                    names_pattern = "(Eye|Hand)(\\d)") |> 
   mutate(Group=paste0("Grp_",Group))
dataLong
# A tibble: 432 x 4
   Group Index   Eye  Hand
   <chr> <chr> <dbl> <dbl>
 1 Grp_1 1     0.162 0.369
 2 Grp_1 2     0.152 1.45 
 3 Grp_1 3     0.329 1.81 
 4 Grp_1 1     0.614 0.75 
 5 Grp_1 2     1.40  2.33 
 6 Grp_1 3     2.31  2.90 
 7 Grp_1 1     0.134 0.35 
 8 Grp_1 2     1.11  1.86 
 9 Grp_1 3     1.29  2.22 
10 Grp_1 1     0.083 0.35 
# ... with 422 more rows

Cors <- dataLong |> group_by(Group,Index) |> summarize(Cor=round(cor(Eye,Hand),3))
`summarise()` has grouped output by 'Group'. You can override using the `.groups` argument.
Cors
# A tibble: 6 x 3
# Groups:   Group [2]
  Group Index   Cor
  <chr> <chr> <dbl>
1 Grp_1 1     0.554
2 Grp_1 2     0.836
3 Grp_1 3     0.876
4 Grp_2 1     0.396
5 Grp_2 2     0.917
6 Grp_2 3     0.919

Reubebe · February 17, 2022, 8:27pm

I find it strange I am using exactly the same code and still getting just one value for Cors
Cors
Cor
1 0.843

FJCC · February 17, 2022, 9:13pm

Please show the actual show the actual code you are running. The best way to do that is with a Reproducible Example (reprex). Here is a tutorial on how to make one.

FAQ: How to do a minimal reproducible example ( reprex ) for beginners Guides & FAQs

A minimal reproducible example consists of the following items: A minimal dataset, necessary to reproduce the issue The minimal runnable code necessary to reproduce the issue, which can be run on the given dataset, and including the necessary information on the used packages. Let's quickly go over each one of these with examples: Minimal Dataset (Sample Data) You need to provide a data frame that is small enough to be (reasonably) pasted on a post, but big enough to reproduce your issue. Let's say, as an example, that you are working with the iris data frame head(iris) #> Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 5.1 3.5 1.4 0.…

Reubebe · February 17, 2022, 9:16pm

dataLong <- data10 %>% pivot_longer(cols = -Group,
names_to=c(".value","Index"),
names_pattern = "(Eye|Hand)(\d)") %>%
mutate(Group=paste0("Grp_",Group))

Cors <- dataLong %>% group_by(Group,Index) %>% summarize(Cor=round(cor(Eye,Hand),3))

ggplot(dataLong,aes(x=Hand,y=Eye))+geom_point()+
facet_grid(Index~Group)+
geom_text(aes(x=4,y=4,label=paste("r=",Cor)),data=Cors)

FJCC · February 17, 2022, 9:34pm

The code you posted worked for me after I fixed the second part of the names_pattern. It is \d in what you posted but it should be \\d. I assume that was caused by the forum software and your R code is correct.
All I can suggest is that you close and restart RStudio, load just the libraries needed for this code and try again.

Reubebe · February 18, 2022, 3:13am

The code works on the cloud but not on my desktop r studio

FJCC · February 18, 2022, 3:43am

If the failure is that the Cors data frame only contains a single value when you run the code locally, that suggests that the group_by() function is not working. I have no idea why that would be. Does this code work on your local system?

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
mtcars |> group_by(carb) |> summarize(avg = mean(mpg))
#> # A tibble: 6 x 2
#>    carb   avg
#>   <dbl> <dbl>
#> 1     1  25.3
#> 2     2  22.4
#> 3     3  16.3
#> 4     4  15.8
#> 5     6  19.7
#> 6     8  15

^{Created on 2022-02-17 by the reprex package (v2.0.1)}

Reubebe · February 18, 2022, 3:57am

It is working now. I think the problem were some packages masking others

system · February 25, 2022, 3:57am

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