I have a problem with the multcompLetters4 function. I have done anova and tukey test and now I want to generate letters for a boxplot with the function. I have seen a youtube video and did it exactly as in the video, but I get an error that I don’t understand.

in my opinion there is no problem, but the error still occurs. i hope someone of you can help me.
Thanks!

This is my code:

SAD_data_Spur_mai_2019 <- SAD_data %>%
filter(Saison == 2019, Monat == 5, Art == “S. purpurea”)

anova <- aov(Geh DT SAD (mg/g) ~ Individuum, data = SAD_data_Spur_mai_2019)
summary(anova)

tukey <- TukeyHSD(anova)
print(tukey)

cld <- multcompLetters4(anova, tukey)
print(cld)

When i run it I get the following error:

Error in [.data.frame(data, , fm[[1]]) :
undefined columns selected

The result of the anova and tukey test is as follows:

summary(anova)
Df Sum Sq Mean Sq F value Pr(>F)
Individuum 7 32006 4572 20.88 6.33e-07 ***
Residuals 16 3503 219

Signif. codes: 0 ‘’ 0.001 ‘’ 0.01 ‘’ 0.05 ‘.’ 0.1 ‘ ’ 1

tukey <- TukeyHSD(anova)
print(tukey)
Tukey multiple comparisons of means
95% family-wise confidence level

Fit: aov(formula = Geh DT SAD (mg/g) ~ Individuum, data = SAD_data_Spur_mai_2019)

$Individuum
diff lwr upr
14_Spur_f_BT-01_Spur_m_BT -26.739473 -68.567057 15.0881111
15_Spur_f_BT-01_Spur_m_BT 26.327669 -15.499915 68.1552532
46_Spur_f_BT-01_Spur_m_BT -41.324086 -83.151670 0.5034978
47_Spur_f_BT-01_Spur_m_BT 23.937801 -17.889782 65.7653854
48_Spur_m_BT-01_Spur_m_BT 56.764234 14.936650 98.5918175
49_Spur_m_BT-01_Spur_m_BT -52.430203 -94.257787 -10.6026190
50_Spur_f_BT-01_Spur_m_BT -36.311685 -78.139269 5.5158991
15_Spur_f_BT-14_Spur_f_BT 53.067142 11.239558 94.8947260
46_Spur_f_BT-14_Spur_f_BT -14.584613 -56.412197 27.2429707
47_Spur_f_BT-14_Spur_f_BT 50.677274 8.849690 92.5048582
48_Spur_m_BT-14_Spur_f_BT 83.503706 41.676122 125.3312904
49_Spur_m_BT-14_Spur_f_BT -25.690730 -67.518314 16.1368538
50_Spur_f_BT-14_Spur_f_BT -9.572212 -51.399796 32.2553719
46_Spur_f_BT-15_Spur_f_BT -67.651755 -109.479339 -25.8241714
47_Spur_f_BT-15_Spur_f_BT -2.389868 -44.217452 39.4377162
48_Spur_m_BT-15_Spur_f_BT 30.436564 -11.391020 72.2641483
49_Spur_m_BT-15_Spur_f_BT -78.757872 -120.585456 -36.9302882
50_Spur_f_BT-15_Spur_f_BT -62.639354 -104.466938 -20.8117702
47_Spur_f_BT-46_Spur_f_BT 65.261888 23.434304 107.0894715
48_Spur_m_BT-46_Spur_f_BT 98.088320 56.260736 139.9159036
49_Spur_m_BT-46_Spur_f_BT -11.106117 -52.933701 30.7214671
50_Spur_f_BT-46_Spur_f_BT 5.012401 -36.815183 46.8399852
48_Spur_m_BT-47_Spur_f_BT 32.826432 -9.001152 74.6540161
49_Spur_m_BT-47_Spur_f_BT -76.368004 -118.195588 -34.5404205
50_Spur_f_BT-47_Spur_f_BT -60.249486 -102.077070 -18.4219024
49_Spur_m_BT-48_Spur_m_BT -109.194437 -151.022020 -67.3668526
50_Spur_f_BT-48_Spur_m_BT -93.075918 -134.903502 -51.2483345
50_Spur_f_BT-49_Spur_m_BT 16.118518 -25.709066 57.9461020
p adj
14_Spur_f_BT-01_Spur_m_BT 0.3933857
15_Spur_f_BT-01_Spur_m_BT 0.4111698
46_Spur_f_BT-01_Spur_m_BT 0.0540480
47_Spur_f_BT-01_Spur_m_BT 0.5215084
48_Spur_m_BT-01_Spur_m_BT 0.0045869
49_Spur_m_BT-01_Spur_m_BT 0.0092309
50_Spur_f_BT-01_Spur_m_BT 0.1145835
15_Spur_f_BT-14_Spur_f_BT 0.0083286
46_Spur_f_BT-14_Spur_f_BT 0.9182967
47_Spur_f_BT-14_Spur_f_BT 0.0122493
48_Spur_m_BT-14_Spur_f_BT 0.0000758
49_Spur_m_BT-14_Spur_f_BT 0.4394725
50_Spur_f_BT-14_Spur_f_BT 0.9911607
46_Spur_f_BT-15_Spur_f_BT 0.0008144
47_Spur_f_BT-15_Spur_f_BT 0.9999990
48_Spur_m_BT-15_Spur_f_BT 0.2547920
49_Spur_m_BT-15_Spur_f_BT 0.0001511
50_Spur_f_BT-15_Spur_f_BT 0.0017916
47_Spur_f_BT-46_Spur_f_BT 0.0011838
48_Spur_m_BT-46_Spur_f_BT 0.0000102
49_Spur_m_BT-46_Spur_f_BT 0.9795015
50_Spur_f_BT-46_Spur_f_BT 0.9998513
48_Spur_m_BT-47_Spur_f_BT 0.1866024
49_Spur_m_BT-47_Spur_f_BT 0.0002154
50_Spur_f_BT-47_Spur_f_BT 0.0026218
49_Spur_m_BT-48_Spur_m_BT 0.0000025
50_Spur_f_BT-48_Spur_m_BT 0.0000200
50_Spur_f_BT-49_Spur_m_BT 0.8727430

i also tried to convert it into a dataframe, but i get the same error.