.vis-item{
  background-color:white;
}
library(tibble)
library(timevis)
data <- tribble(~id, ~content, ~start, ~end,
                1,  "CSS 1", "1996-12-17", NA, 
                2,  "CSS 2", "1998-05-01", NA, 
                3,  "CSS 3", "1999-06-01", NA, 
                4,   "HTML", "1989-01-01", NA, 
                5, "HTML 2", "1995-11-24", NA, 
                6, "HTML 3", "1997-01-14", NA, 
                7, "HTML 4", "1997-12-18", NA,
                8, "HTML 5", "2014-10-28", NA, 
                9,    "CSS", "1994-10-10", NA, 
                10,    "JS", "1995-12-04", NA)

timevis(data)
library(tidyverse)
## ── Attaching packages ─────────────────────────────────────── tidyverse 1.3.0 ──
## ✓ ggplot2 3.3.2     ✓ dplyr   1.0.1
## ✓ tidyr   1.1.1     ✓ stringr 1.4.0
## ✓ readr   1.3.1     ✓ forcats 0.5.0
## ✓ purrr   0.3.4
## ── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
library(knitr)
library(lubridate)
## 
## Attaching package: 'lubridate'
## The following objects are masked from 'package:base':
## 
##     date, intersect, setdiff, union
library(gridExtra)
## 
## Attaching package: 'gridExtra'
## The following object is masked from 'package:dplyr':
## 
##     combine
library(kableExtra)
## 
## Attaching package: 'kableExtra'
## The following object is masked from 'package:dplyr':
## 
##     group_rows
library(reprex)
data("economics")
data("economics_long")

##exercise1

demol<-ggplot()+
  geom_line(data=economics,aes(x=date,y=pop,colour="blue"))+
  geom_line(data=economics,aes(x=date,y=pop,shape="triangle",colour="red"))
## Warning: Ignoring unknown aesthetics: shape
reprex::reprex()
## No input provided and clipboard is not available.
## Rendering reprex...