How to draw geom_line with 4 groups and how to limit x-axis with no data

Question

Data: Group Year Month Mean Group 1 2018 Jun 1.58 Group 1 2018 Jul 0.92 Group 1 2018 Aug 3.52 Group 1 2018 Sep 5.9 Group 1 2018 Oct 5.95 Group 1 2018 Nov 11.21 Group 1 2018 Dec 13.55 Group 1 2019 Jan 4.67 Group 1 2019 Feb 4.35 Group 1 2019 Mar 4.04 Group 1 2019 Apr 1.33 Group 1 2019 May 20.5 Group 1 2019 Jun 1 Group 1 2019 Jul 2.67 Group 1 2019 Aug 5.79 Group 1 2019 Sep 3.95 Group 1 2019 Oct 1.83 Group 1 2019 Nov 5 Group 1 2019 Dec 12.95 Group 1 2020 Jan 8.89 Group 1 2020 Feb 0.75 Group 2 2018 Jun 0 Group 2 2018 Jul 1.2 Group 2 2018 Aug 1.83 Group 2 2018 Sep 3.29 Group 2 2018 Oct 3.32 Group 2 2018 Nov 1 Group 2 2018 Dec 6 Group 2 2019 Jan 0 Group 2 2019 Feb 2.25 Group 2 2019 Mar 2.14 Group 2 2019 Apr 1.94 Group 2 2019 May 0 Group 2 2019 Jun 0.2 Group 2 2019 Jul 1.25 Group 2 2019 Aug 2.86 Group 2 2019 Sep 7.93 Group 2 2019 Oct 3.25 Group 2 2019 Nov 2.8 Group 2 2019 Dec 2 Group 2 2020 Jan 0.25 Group 2 2020 Feb 1.33 Group 3 2018 Jun 0.11 Group 3 2018 Jul 0.68 Group 3 2018 Aug 1.3 Group 3 2018 Sep 0.99 Group 3 2018 Oct 2.67 Group 3 2018 Nov 9.89 Group 3 2018 Dec 9.81 Group 3 2019 Jan 2.78 Group 3 2019 Feb 3.97 Group 3 2019 Mar 5.75 Group 3 2019 Apr 2.19 Group 3 2019 May 0.95 Group 3 2019 Jun 0 Group 3 2019 Jul 1.31 Group 3 2019 Aug 3.77 Group 3 2019 Sep 1.79 Group 3 2019 Oct 3.14 Group 3 2019 Nov 1.82 Group 3 2019 Dec 6.5 Group 3 2020 Jan 2.72 Group 3 2020 Feb 1.33 Group 4 2018 Jun 2.4 Group 4 2018 Jul 0.98 Group 4 2018 Aug 1.1 Group 4 2018 Sep 2.32 Group 4 2018 Oct 6.7 Group 4 2018 Nov 15.66 Group 4 2018 Dec 8.18 Group 4 2019 Jan 3.69 Group 4 2019 Feb 0.8 Group 4 2019 Mar 0.04 Group 4 2019 Apr 1.17 Group 4 2019 May 7 Group 4 2019 Jun 0.53 Group 4 2019 Jul 2.93 Group 4 2019 Aug 2.73 Group 4 2019 Sep 2.07 Group 4 2019 Oct 6.59 Group 4 2019 Nov 3.91 Group 4 2019 Dec 7.2 Group 4 2020 Jan 6.81 Group 4 2020 Feb 0.8

Data$Month <- factor(Data$Month, levels = month.abb) Data$Year <- factor(Data$Year, levels = c("2018", "2019", "2020")) Data %>% filter(Group == "Group 1") %>% ggplot(aes(x = Month, y = Mean))+ geom_point() + geom_line(aes(colour = Year), group = 1) + facet_grid(~ Year) + theme_minimal() + theme(legend.position = "none")

1. Is it possible to draw a line graph GroupWise.
2. How to remove x-axis labels with no data.plot (Jan:May in 2018, Mar:Dec in 2020)

Answer 1

You were quite close. This should do it:

Data  <- read.table(text=
"Group  Year    Month   Mean
1   2018    Jun 1.58
1   2018    Jul 0.92
1   2018    Aug 3.52
1   2018    Sep 5.9
1   2018    Oct 5.95
1   2018    Nov 11.21
1   2018    Dec 13.55
1   2019    Jan 4.67
1   2019    Feb 4.35
1   2019    Mar 4.04
1   2019    Apr 1.33
1   2019    May 20.5
1   2019    Jun 1
1   2019    Jul 2.67
1   2019    Aug 5.79
1   2019    Sep 3.95
1   2019    Oct 1.83
1   2019    Nov 5
1   2019    Dec 12.95
1   2020    Jan 8.89
1   2020    Feb 0.75
2   2018    Jun 0
2   2018    Jul 1.2
2   2018    Aug 1.83
2   2018    Sep 3.29
2   2018    Oct 3.32
2   2018    Nov 1
2   2018    Dec 6
2   2019    Jan 0
2   2019    Feb 2.25
2   2019    Mar 2.14
2   2019    Apr 1.94
2   2019    May 0
2   2019    Jun 0.2
2   2019    Jul 1.25
2   2019    Aug 2.86
2   2019    Sep 7.93
2   2019    Oct 3.25
2   2019    Nov 2.8
2   2019    Dec 2
2   2020    Jan 0.25
2   2020    Feb 1.33
3   2018    Jun 0.11
3   2018    Jul 0.68
3   2018    Aug 1.3
3   2018    Sep 0.99
3   2018    Oct 2.67
3   2018    Nov 9.89
3   2018    Dec 9.81
3   2019    Jan 2.78
3   2019    Feb 3.97
3   2019    Mar 5.75
3   2019    Apr 2.19
3   2019    May 0.95
3   2019    Jun 0
3   2019    Jul 1.31
3   2019    Aug 3.77
3   2019    Sep 1.79
3   2019    Oct 3.14
3   2019    Nov 1.82
3   2019    Dec 6.5
3   2020    Jan 2.72
3   2020    Feb 1.33
4   2018    Jun 2.4
4   2018    Jul 0.98
4   2018    Aug 1.1
4   2018    Sep 2.32
4   2018    Oct 6.7
4   2018    Nov 15.66
4   2018    Dec 8.18
4   2019    Jan 3.69
4   2019    Feb 0.8
4   2019    Mar 0.04
4   2019    Apr 1.17
4   2019    May 7
4   2019    Jun 0.53
4   2019    Jul 2.93
4   2019    Aug 2.73
4   2019    Sep 2.07
4   2019    Oct 6.59
4   2019    Nov 3.91
4   2019    Dec 7.2
4   2020    Jan 6.81
4   2020    Feb 0.8
", header=TRUE)

Data <- Data %>% mutate(
            Group = paste("Group",Group),
            Year = factor(Year),
            Month = factor( Month, levels = month.abb )
        )

Data %>%
    ggplot(aes(x = Month, y = Mean, group=Group)) +
    geom_point() +
    geom_line(aes(colour = Group)) +
    facet_grid(~ Year, scales = "free_x") +
    theme_minimal() +
    theme(legend.position = "none")

(Note I had to ommit 'Group' from my input data since I was pasting of the data dump in your post, otherwise read.table can't easily make sense of the space, that's why I paste it back in. It's not important for the solution)