[R] How to differ stats_cor labels by group on a ggplot

Rui Barradas ru|pb@rr@d@@ @end|ng |rom @@po@pt
Sun Jul 12 21:09:10 CEST 2020


Hello,

The code below puts the group names as subscripts to 'R'.
The trick is to create each of the labels with those names before 
pasting the ..p.label..
This is done by Map, calling a function f defined outside the for loop.

I have also changed your code a bit, simplifying parts of it.

1. I have named the data set df1, since df already is a base R function.
2. Instead of redefining theme() elements in the loop, I have created a 
custom one.
3. The for loop runs directly through the names of the data set df1, not 
through indices into them.
4. df1[[i]] is the same as unlist(df1[i]). And simpler.
5. After testing the code with df1[[i]], there were warnings, telling to 
use the pronoun .data, which I do.
6. The code repeated itself a lot, if you define aesthetics in the 
initial call to ggplot, there is no need to redefine them in the layers 
calls unless you are changing them. For instance, after

ggplot(df, mapping=aes(x = Age, y = unlist(df[i]), color=factor(AgeGroup)))


you don't have to define the same y and color again:

stat_cor(aes(color = factor(AgeGroup), y = unlist(df[i]))


7. Some arguments (method = "pearson" and others) didn't change their 
default values and were removed.


Now the code.
Note that before writing to file, the filename is output to stdin, 
remove it, it's not part of your original code.



theme_custom_ps <- function(){

   theme_classic() %+replace%    # replace elements we want to change

     theme(axis.text.x = element_text(face = "bold", size = 14),
           axis.text.y = element_text(face = "bold", size = 14),
           axis.title.x = element_text(face = "bold", size = 14),
           axis.title.y = element_text(face = "bold", size = 14),
           legend.text = element_text(face = "bold", size = 14, colour = 
"black"),
           legend.title = element_text(size = 12, colour = "black")
     )
}


library(ggplot2)
library(ggpubr)

df1 <- read.table("sim_data.txt", header = TRUE)

group_name <- c("old", "young")
f <- function(grp, rlab) sub("R", paste0("R[", grp, "]"), rlab)

for (i in names(df1)[3:6]) {
   p1 <- ggplot(df1, mapping = aes(x = Age, y = .data[[i]], color = 
factor(AgeGroup))) +
     geom_point(size = 4) +
     geom_smooth(method = "lm", formula = y ~ x) +
     geom_smooth(mapping = aes(group = 1), method = "lm", formula = y ~ x) +
     stat_cor(aes(label = paste(Map(f, group_name, ..r.label..), 
..p.label.., sep = "~`,`~")),
              label.x.npc = "center",
              show.legend = FALSE) +
     stat_cor(aes(label = paste(sub("R", expression("R"[overall]), 
..r.label..), ..p.label.., sep = "~`,`~"),
                  group = 1, color = "black"),
              label.y = 0.5,
              label.x.npc = "center",
              position = position_nudge(y = 0.015 * 0.5),
              show.legend = FALSE) +
     scale_colour_discrete(name = "Group", labels = c("Young", "Old", 
"Overall")) +
     scale_x_continuous(breaks = seq(20, 90, by = 10)) +
     scale_y_continuous(breaks = seq(0.1, 0.5, by = 0.1)) +
     expand_limits(y = 0.5) +
     ylab(i) +
     theme_custom_ps()

   pngfile <- paste0("TestAge_", i, ".png")
   cat("filename:", pngfile, "\n")
   ggsave(p1, file = pngfile, scale = 1, width = 16, height = 10, units 
= "cm")
}


So it seems this is worth the effort after all.
Just trickier than expected.


Hope this helps,

Rui Barradas

Às 02:20 de 12/07/20, Paulina Skolasinska escreveu:
> Sorry for misspelling your name, Jim. Well, it seems this is not worth the effort then. If my advisor decides this is absolutely essential, I�ll add it in gimp or something. Thanks for giving it a go, Jim.
> 
> Get Outlook for iOS<https://aka.ms/o0ukef>
> ________________________________
> From: Jim Lemon <drjimlemon using gmail.com>
> Sent: Saturday, July 11, 2020 6:32:13 PM
> To: Paulina Skolasinska <paulina.skol using hotmail.com>
> Cc: r-help using r-project.org <r-help using r-project.org>
> Subject: Re: [R] How to differ stats_cor labels by group on a ggplot
> 
> Hi Paulina,
> Thanks for the data. Even after downloading a ton of packages along
> with the "ggpubr" package, I get a namespace error when I try to load
> it. After a bit of wrangling, I did get the code to run without the
> "stat_cor" function, producing the four PNG images. My best guess is
> to try the geom_label function with stat="cor", but I can't see any
> argument to format the actual label. I think this is about as far as
> I'm going to get.
> 
> Jim
> 
> On Sun, Jul 12, 2020 at 12:09 AM Paulina Skolasinska
> <paulina.skol using hotmail.com> wrote:
>>
>> Thanks Tim, here is the link to the data: https://we.tl/t-c4x9Lw7LeR
>> I'm posting my code again so it better matches the modified data, and because I've added several improvements in the meantime.
>>
>> for (i in 3:6) {
>>      p1 <- ggplot(df, mapping=aes(x = Age, y = unlist(df[i]), color=factor(AgeGroup))) +
>>          geom_smooth(method="lm") +
>>          geom_point(size = 4) +
>>          scale_x_continuous(breaks = seq(20,90, by=10)) +
>>          scale_y_continuous(breaks = seq(0.1,0.5, by=0.1)) +
>>          theme_classic() +
>>          expand_limits(y = 0.5) +
>>          ylab(names(df)[i]) +
>>          theme(axis.text.x = element_text(face="bold", size=14),
>>                axis.text.y = element_text(face="bold", size=14),
>>                axis.title.x = element_text(size=14, face="bold"),
>>                axis.title.y = element_text(size=14, face="bold"),
>>                legend.title = element_text(color="black", size=12),
>>                legend.text = element_text(colour="black", size = 14, face = "bold")) +
>>          geom_smooth(data=df, mapping = aes(x = Age, y = unlist(df[i]), group=1, color="black"), method = "lm") +
>>          scale_colour_discrete(name="Group", labels=c("Young", "Old", "Overall")) +
>>          stat_cor(aes(color = factor(AgeGroup), y = unlist(df[i])),
>>                   method = "pearson", label.x.npc = c("center"), label.y.npc="top") +
>>          stat_cor(aes(x = Age, y = unlist(df[i]),
>>                   label = paste(sub("R",expression("R"[overall]),..r.label..), ..p.label.., sep = "~`,`~"),
>>                   group=1, color="black"), method = "pearson",label.y=0.5, label.x.npc = c("center"),
>>                   position = position_nudge(y = 0.015 * 0.5))
>>
>>      ggsave(p1, file=paste0("TestAge_", names(df)[i], ".png"), scale=1, width=16, height=10, units="cm")
>> }
>>
>>
>> ________________________________
>> Od: Jim Lemon <drjimlemon using gmail.com>
>> Wys�ane: sobota, 11 lipca 2020 04:09
>> Do: Paulina Skolasinska <paulina.skol using hotmail.com>
>> DW: r-help using r-project.org <r-help using r-project.org>
>> Temat: Re: [R] How to differ stats_cor labels by group on a ggplot
>>
>> Hi Paulina,
>> Without data it's hard to work out what you are doing. Even a small
>> simulated data set would help to get answers.
>>
>> Jim
>>
>> On Fri, Jul 10, 2020 at 11:49 PM Paulina Skolasinska
>> <paulina.skol using hotmail.com> wrote:
>>>
>>> 'm using ggplot2 to plot two variables at a time. I'm plotting two age groups and overall data on the same graph. I'm also using stat_cor form the ggpubr package to report correlations for the two groups and overall data.
>>>
>>> I want each stat_cor label to have a custom subscript - the group name ("old", "young"). I have managed to do this for the overall data, but I don't know how to add custom labels for each group separately. I'd like the labels to look like this: https://imgur.com/a/naF7uNW
>>>
>>>> for (i in 18:21) {
>>>    p1 <- ggplot(df, mapping=aes(x = Age, y = unlist(df[i]), color=factor(AgeGroup))) +
>>>      geom_smooth(method="lm") +
>>>      geom_point(size = 4) +
>>>      geom_smooth(data=df, mapping = aes(x = Age, y = unlist(df[i]), group=1, color="black"), method = "lm") +
>>>      scale_colour_discrete(name="Group", labels=c("young", "old", "overall")) +
>>>      stat_cor(aes(color = factor(AgeGroup), y = unlist(df[i]))) +
>>>      stat_cor(aes(x = Age, y = unlist(df[i]), group=1, color="black",
>>>                   label = paste(sub("R",expression("R"[overall]),..r.label..), ..p.label.., sep = "~`,`~")))
>>>
>>>    ggsave(p1, file=paste0("Age_", names(df)[i], ".png"), scale=1)
>>> }
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> 
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> 
> 
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> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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> and provide commented, minimal, self-contained, reproducible code.
>



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