update session_2

session_2/session_2.Rmd

 ---
 title: "R.2: introduction to Tidyverse"
-author: "Laurent Modolo [laurent.modolo@ens-lyon.fr](mailto:laurent.modolo@ens-lyon.fr), Hélène Polvèche [hpolveche@istem.fr](mailto:hpolveche@istem.fr)"
-date: "2021"
+author: "Laurent Modolo [laurent.modolo@ens-lyon.fr](mailto:laurent.modolo@ens-lyon.fr);\nHélène Polvèche [hpolveche@istem.fr](mailto:hpolveche@istem.fr)"
+date: "2022"
 output:
   rmdformats::downcute:
     self_contain: true
     use_bookdown: true
     default_style: "light"
     lightbox: true
-    css: "http://perso.ens-lyon.fr/laurent.modolo/R/src/style.css"
+    css: "../www/style_Rmd.css"
 ---
 
+```{r include=FALSE}
+library(fontawesome)
+``` 
+
+ `r fa(name = "fas fa-house", fill = "grey", height = "1em")`  https://can.gitbiopages.ens-lyon.fr/R_basis/
+
 ```{r setup, include=FALSE}
 rm(list=ls())
 knitr::opts_chunk$set(echo = TRUE)
@@ -500,7 +506,7 @@ ggplot(data = mpg, mapping = aes(x = displ, y = hwy, color = drv)) +
 </p>
 </details>
 
-## See you in [R.3: Transformations with ggplot2](http://perso.ens-lyon.fr/laurent.modolo/R/session_3/)
+## See you in [R.3: Transformations with ggplot2](https://can.gitbiopages.ens-lyon.fr/R_basis/session_3/)
 
 # To go further: publication ready plots
 
@@ -537,10 +543,17 @@ p1 + theme_minimal()
 You may have to combine several plots, for that you can use the `cowplot` package which is a `ggplot2` extension.
 First install it :
 
+
 ```{r, eval=F}
 install.packages("cowplot")
 ```
 
+```{r, include=F, echo =F}
+if (! require("cowplot")) {
+  install.packages("cowplot")
+}
+```
+
 Then you can use the function `plot` grid to combine plots in a publication ready style:
 
 ```{r,message=FALSE}