Multiple variable plot, line style and thickness, black and white - r

Question

Hey there I'm new to R and have a very small question
I have the following dataset:
head(risk_free_rate_comparison)
Dates ` Swap rate` `Sovereign bond yield rate` `Swap rate - Sovereign bond yield rate`
<dttm> <dbl> <dbl> <dbl>
1 2007-01-02 408.9 380.9568 27.9432
2 2007-01-03 410.3 380.4535 29.8465
3 2007-01-04 409.2 381.3993 27.8007
4 2007-01-05 414.3 385.0663 29.2337
5 2007-01-08 413.1 384.2545 28.8455
6 2007-01-09 415.5 384.9770 30.5230
,with the following plot:
ggplot(d, aes(Dates, value, color = variable, linetype = variable)) +
+ geom_line() +
+ labs(color = NULL, linetype = NULL) +
+ theme_classic() +
+ theme(legend.position = "bottom") +
+ ylab("Rates in bp")
+ theme(
+ legend.position = "bottom",
+ legend.direction = "vertical",
+ legend.box.margin = margin(t = 20),
+ axis.title.x = element_text(margin = margin(t = 20)),
+ axis.title.y = element_text(margin = margin(r = 20))
+ )
Now I would like to change the line colours of the three variables to black and white style. And maybe varying line thicknesses or something in that way in order to be able to distinguish the lines.

Answer 1

#rbonac, see if this helps you out, and feel free to experiment by commenting out different layers or using scale_line_manual() to set your colors manually.
library(tidyverse)
mtcars %>%
mutate(cyl = factor(cyl, labels = c("4", "6", "8"))) %>%
ggplot(., aes(wt, mpg, color = cyl, linetype = cyl)) +
geom_line(size = 2) +
labs(color = NULL, linetype = NULL) +
theme_classic() +
ylab("Rates in bp") +
scale_linetype_discrete() +
scale_color_grey() +
theme(
legend.position = "bottom",
legend.direction = "vertical",
legend.box.margin = margin(t = 30),
axis.title.x = element_text(margin = margin(t = 20))
)

Answer 2

You can assign each variable to a line width using size aesthetic, and manually change line color and size to desired values using scale_colour_manual and scale_size_manual
ggplot(d, aes(Dates, value, color = variable)) +
geom_line(aes(linetype = variable, size=variable)) +
labs(color = NULL, linetype = NULL, size = NULL) +
theme_classic() +
theme(legend.position = "bottom") +
ylab("Rates in bp") +
scale_colour_manual(values=c("gray50", "gray25", "gray0")) +
scale_size_manual(values=c(1, 1.5, 2)) +
theme(
legend.position = "bottom",
legend.direction = "vertical",
legend.box.margin = margin(t = 20),
axis.title.x = element_text(margin = margin(t = 20)),
axis.title.y = element_text(margin = margin(r = 20))
)