R help - Feb 2021 - Axis whitout all the row, that contains time

Hello,

In order to select every 20 s, set the date_breaks = "20 secs", not
the
breaks.
The axis labels are also formatted, with date_labels, standard datetime 
format strings are used for this. And rotated, not part of the question.

# Create some data
set.seed(2021)
time <- seq(as.POSIXct("2021-02-11"), as.POSIXct("2021-02-11
00:29:59"),
by = "1 secs")
y <- cumsum(rnorm(length(time)))
df1 <- data.frame(time, y)

# Plot the data
library(ggplot2)

ggplot(df1, aes(time, y)) +
   geom_line() +
   scale_x_datetime(date_breaks = "20 secs", date_labels =
"%M:%S") +
   theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1, 
size = 5))


Hope this helps,

Rui Barradas

?s 15:05 de 12/02/21, Informatique escreveu:
> Hello,
> 
> i'm using Rstudio from a few day, and i have some information in a CVS
file, take every five second, format of the time is HH:MM:SS.
> I use the hour on the X axis, but i don't want having all the time
print. For example only every 10 values.
> 
> I think it will be possible with   scale_x_datetime(breaks =
date_breaks(XXX)
> 
> but i don't understand how select every 20 s.
> 
> Thank's for your help
> 
> Fran?ois-marie BILLARD
>

Hello,

the time are in the first table like that :	10:24:00
and i use this for  
	listeMesuresPropres$Heure. <- hms(listeMesuresPropres$Heure.
after time ar like that : 		10H 24M 0S
and when i use  with ggplot
  scale_x_time(breaks = "20 secs",labels = "%H:%M:%S") 

it have the graphics but noting write on the X axis.

I think it a problem with the format of the time, because if i try a ggplot
without scale_x_time i don't have anything on the graphic.

Thank's 

Fran?ois-Marie BILLARD

On Fri, 12 Feb 2021 18:24:35 +0000
Rui Barradas <ruipbarradas at sapo.pt> wrote:
> Hello,
> 
> In order to select every 20 s, set the date_breaks = "20 secs",
not the
> breaks.
> The axis labels are also formatted, with date_labels, standard datetime 
> format strings are used for this. And rotated, not part of the question.
> 
> # Create some data
> set.seed(2021)
> time <- seq(as.POSIXct("2021-02-11"),
as.POSIXct("2021-02-11 00:29:59"),
> by = "1 secs")
> y <- cumsum(rnorm(length(time)))
> df1 <- data.frame(time, y)
> 
> # Plot the data
> library(ggplot2)
> 
> ggplot(df1, aes(time, y)) +
>    geom_line() +
>    scale_x_datetime(date_breaks = "20 secs", date_labels =
"%M:%S") +
>    theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1, 
> size = 5))
> 
> 
> Hope this helps,
> 
> Rui Barradas
> 
> ?s 15:05 de 12/02/21, Informatique escreveu:
> > Hello,
> > 
> > i'm using Rstudio from a few day, and i have some information in a
CVS file, take every five second, format of the time is HH:MM:SS.
> > I use the hour on the X axis, but i don't want having all the time
print. For example only every 10 values.
> > 
> > I think it will be possible with   scale_x_datetime(breaks =
date_breaks(XXX)
> > 
> > but i don't understand how select every 20 s.
> > 
> > Thank's for your help
> > 
> > Fran?ois-marie BILLARD
> > 

-- 
Informatique <informatique at billard-francois-marie.eu>