在ggplot2中缩放x轴

Question

I have issues with the x-axis when plotting a line graph. As the graph below indicates, I have too many labels.

I try to remedy the solution by including only some labels using seq() , but I would come across this error:

ggplot(df, aes(x = date, y = measure, group = 1)) + 
    geom_line() + 
    theme_bw() +
    theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust = 0.5)) + 
    xlab("X-Axis") + 
    ylab("Y-Axis") + 
    scale_x_continuous(breaks = round(seq(min(df$date), max(df$date), by = 221.2), 1))

#> Error in seq.default(min(df$date), max(df$date),  : 
#>   'from' must be a finite number
#> In addition: Warning message:
#> In seq.default(min(df$date), max(df$date),  :
#>   NAs introduced by coercion

Any suggestions? If it helps, df$date is considered a character. Perhaps, I should convert it to numeric or as a datetime?

Answer 1

Remove scale_x_continuous. Make sure your date is a date. You can do that with as.Date(date). Add below:

+ scale_x_date(date_breaks = "1 month")

Source: http://ggplot2.tidyverse.org/reference/scale_date.html