week9_1.Rmd

---
title: "week9 _1"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## R Markdown

This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see <http://rmarkdown.rstudio.com>.

When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

```{r cars}
summary(cars)
```

## Including Plots

You can also embed plots, for example:

```{r pressure, echo=FALSE}
plot(pressure)
```

Note that the `echo = FALSE` parameter was added to the code chunk to prevent printing of the R code that generated the plot.


typeof(c("John", "Mary"))
typeof(c(2, 3.1412))
typeof(c(TRUE, TRUE, F))


class(c("John", "Mary"))
class(c(2, 3.1412))
class(c(TRUE, TRUE, F))


dateTimeInfo<-"2021-01-01 12:03:33"

typeof(dateTimeInfo)

class(dateTimeInfo)

dateTimeInfo + 20

"2021-01-01 12:03:33" + "20 seconds"
install.packages("lubridate")

lubridate::ymd_hms("2021-01-01 12:03:33") 
lubridate::ymd_hms("2021-01-01 12:03:33") + lubridate::seconds(20)

lubridate::ymd_hms("2021-01-01 12:03:33") + lubridate::seconds(30)

dateTimeInfo2<-"2021-01-01 12:03:33"


dateTimeInfo2<-lubridate::ymd_hms("2021-01-01 12:03:33") 

class(dateTimeInfo2)

dateTimeInfo2+lubridate::seconds (+50)

type: store "raw"info
class: what R can do with different infos