Line plot with multible lines with data from Excel - r

Question

I have a table in Excel that show which weapon where used to commit murder per year.
I want to read the data and plot it as a line plot with multiple lines:
However my code only gives me a gibberish graph:
This is my code:
library("readxl")
library(data.table)
library(ggplot2)
# Read excel data
res <- as.data.frame(readxl::read_excel("murders_per_modus_veapon.xlsx", sheet = 1))
res$r = c('Unknown','Knife/stabbing weapon','Axe','Firearms','Suffocation','Blunt violence','Other')
res = reshape::melt(res)
# Plot data
ggplot(res, aes(x=variable,y=value))+ geom_line()

Answer 1

You need to convert your variable column from factor to date. See below;
library(reshape2)
library(dplyr)
library(lubridate)
library(ggplot2)
reshape2::melt(res, value.name = "MR", variable.name = "Year") %>%
mutate(Year = make_date(as.character(Year), 1, 1)) %>%
ggplot(., aes(x=Year, y=MR, color = Modus)) +
geom_line() +
scale_x_date(date_breaks = "1 year",date_labels = "%Y")
#> Using Modus as id variables
Created on 2021-05-25 by the reprex package (v2.0.0)
Data:
read.table(text = "Modus 2018 2019 2020
Unknown 2 0 0
Knife_stabbing_weapon 8 14 16
Axe 1 1 0
Firearms 3 3 2
Suffocation 2 5 6
Blunt_violence 8 3 4
Other 1 1 0",
header = T, stringsAsFactors = F, check.names = F) -> res
You can still run this part from your own code to import the data, and then use mine for plotting;
res <- as.data.frame(readxl::read_excel("murders_per_modus_veapon.xlsx", sheet = 1))
res$r = c('Unknown','Knife/stabbing weapon','Axe','Firearms',
'Suffocation','Blunt violence','Other')

Answer 2

Since you have not provided reproducible data, I created tiny data that may look like a small subset of your original xlsx data:
df = data.frame(weapon = c("Unknown", "knife", "axe"),
x2018 = c(2, 8, 1),
x2019 = c(0, 14, 1),
x2020 = c(0, 16, 0))
Then, I make the data tidy using dplyr and tidyr. Finally I produce a line plot that you may be looking for:
df %>%
pivot_longer(cols = 2:4, names_to = "year", values_to = "amount") %>%
mutate(year = gsub("x", "", year)) %>%
ggplot(aes(as.numeric(year), amount, col = weapon)) +
geom_line() +
scale_x_continuous(breaks = c(2018, 2019, 2020))

Answer 3

This could be an option. Thanks to M-- for the data.
library(ggplot2)
library(ggrepel)
df <- df %>%
pivot_longer(
cols = c("2018", "2019", "2020")
) %>%
mutate(label = if_else(name == max(name), as.character(Modus), NA_character_)) %>%
mutate(name = as.factor(name))
p <- ggplot(df, aes(x=name, y=value, colour=Modus, group=Modus)) +
geom_point () +
geom_line(size = 0.8) +
theme_bw()
p + geom_label_repel(aes(label = label),
nudge_x = 1,
na.rm = TRUE) +
theme(legend.position = "none")