how to plot time series plot in r?

Question

I want to plot a time series for data in seconds. I tried to use ggplot with this:

p <- ggplot(df_new, aes(x=Time, y=Price)) + 
     geom_line(aes(color = Price), size = 1)

The output is like this:

However, the line is not clear, can anyone help me.

Answer 1

You can separate date from time and try creating a heatmap with geom_tile() .

    library(ggthemes)
    library(ggplot2)
    library(tidyverse)


ggplot(df, aes(x = Time, y = Price, group=1)) + 
  geom_line(linetype = "dashed" , color="red", lwd=1)+
  geom_point(color="blue",size=3)+
  labs(x="Date and Time", y="Price")+
  coord_flip()+
  theme_clean()+
  theme(axis.text.x = element_text(angle= 45, hjust = 1, face="bold", size=12, color="black"), 
        axis.title.x = element_text(face="bold", size=16, color="black"),
        axis.text.y = element_text(face="bold", size=12, color="black"),
        axis.title.y = element_text(face="bold", size=16, color="black"))+
  scale_x_discrete(labels=df$Time)

Plot:

or without flipping the plot

You can separate Date and Time with this code:

df <- separate(df, col = Time, into  = c('Date', 'Time'), sep = ' ')

Plot:

I would suggest using geom_tile()

Sample code:

library(ggplot2)
library(ggthemes)
library(tidyverse)

df <- separate(df, col = Time, into  = c('Date', 'Time'), sep = ' ')
ggplot(df, aes(x = Time, y = Date)) + 
  geom_tile(aes(fill = Price))+
  labs(x="Time", y="Date")+
  theme_pander()+
  theme(axis.text.x = element_text(angle=45,hjust = 1, face="bold", size=12, color="black"), 
        axis.title.x = element_text(face="bold", size=16, color="black"),
        axis.text.y = element_text(face="bold", size=12, color="black"),
        axis.title.y = element_text(face="bold", size=16, color="black"),
        legend.text = element_text(color = "black", size = 16,face="bold"),
        legend.title = element_text(face="bold", size=16, color="black"),
        legend.position="right",
        legend.background = element_rect(color = NA, size=4),
        legend.key.size = unit(1, 'cm'))

Plot:

Sample data:

df<-structure(list(Time = c("2018-02-21 09:00:00", "2018-02-21 09:07:38", 
"2018-02-21 09:09:10", "2018-02-21 09:09:10", "2018-02-21 09:09:21", 
"2018-02-21 09:13:16"), Price = c(122.1, 122.4, 122.4, 122.4, 
122.2, 122.3)), row.names = c(NA, -6L), class = c("tbl_df", "tbl", 
"data.frame"))

Answer 2

Something like this?

library(lubridate)
library(tidyverse)

df %>%
  distinct() %>% 
  mutate(Time = period_to_seconds(hms(format(strptime(Time, "%Y-%m-%d %H:%M:%OS"), "%H:%M:%S"))),
         Time = cumsum(Time - lag(Time, default = first(Time)))) %>% 
  ggplot(aes(x = Time, y = Price)) +
  geom_line() +
  theme_bw()

Output

Or if you are wanting to show the full date, then you could do something like this:

df %>%
  mutate(Time = as.POSIXct(Time, format = "%Y-%m-%d %H:%M:%OS")) %>%
  ggplot(aes(x = Time, y = Price)) +
  geom_line() +
  theme_bw() +
  scale_x_datetime(breaks = "60 sec", date_labels =  "%H:%M:%S")