4.1 4.2

---
title: "ch4"
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.
```{r}
typeof(c("John", "Mary"))
typeof(c(2, 3.1412))
typeof(c(TRUE, TRUE, F))
```

```{r}
class(c("John", "Mary"))
class(c(2, 3.1412))
class(c(TRUE, TRUE, F))
```

```{r}
datetimeinfo<-"2021-01-01 12:03:33" 

```

```{r}
install.packages("lubridate")
```
```{r}
datetimeiofo2<-lubridate::ymd_hms("2021-01-01 12:03:33") + lubridate::seconds(20)
class(datetimeiofo2)
```

```{r}
commonClasses <- list()
```

```{r}
# save three different atomic vectors
commonClasses$character <- c("John", "Mary", "Bill")
commonClasses$numeric <- c(2.3, 4, 7)
commonClasses$logical <- c(TRUE, T, F, FALSE)
```

```{r}
# check each atomic vector class
class(commonClasses$character) # name call on commonClasses to get its value then retrieve the element value whose element name is "character"

class(commonClasses$numeric)
class(commonClasses$logical)
```

```{r}
bloodTypes <- c("AB", "AB", "A", "B", "A", "A", "B", "O", "O", "AB")
```

```{r}
bloodTypes_fct <- 
  factor(bloodTypes)
bloodTypes_fct 
```

```{r}
table(bloodTypes_fct)
```

```{r}
levels(bloodTypes_fct)
```

```{r}
bloodTypes_fct_levelsSetup <- 
  factor(bloodTypes, levels=c("A", "B", "O", "AB"))
bloodTypes_fct_levelsSetup
```

```{r}
class(bloodTypes_fct_levelsSetup)
```

```{r}
table(bloodTypes_fct_levelsSetup)
```

```{r}
household_income <- c("low income", "low income", "middle income", "low income", "high income", "middle income", "high income", "high income", "middle income", "middle income")
```

```{r}
household_income_fct <- 
  factor(household_income)
levels(household_income_fct)
```

```{r}
household_income_fct_levelsSetup <-
  factor(household_income, levels = c("low income", "middle income", "high income"))
levels(household_income_fct_levelsSetup)
```

```{r}
table(household_income_fct_levelsSetup)
```

```{r}
household_income_fct_levelsSetup[[1]]
household_income_fct_levelsSetup[[1]] > "low income"
```

```{r}
household_income_fct_levelsSetup_ordered <-
  factor(
    household_income, 
    levels = c("low income", "middle income", "high income"),
    ordered = T
    )
household_income_fct_levelsSetup_ordered 
```

```{r}
household_income_fct_levelsSetup_ordered[[1]]
household_income_fct_levelsSetup_ordered[[1]] > "low income"

household_income_fct_levelsSetup_ordered[[3]]
household_income_fct_levelsSetup_ordered[[3]] > "low income"
```

```{r}
commonClasses$ordered_factor <- household_income_fct_levelsSetup_ordered
class(commonClasses$ordered_factor)
```

```{r}
#exercise 4.1
customerExperience <- c('very happy','very happy','satisfied','satisfied','satisfied','very happy','bad','bad','satisfied','satisfied','bad','happy','happy','very happy','happy','happy','satisfied','very happy','very happy','satisfied','satisfied','very happy','satisfied','bad','very happy','very bad','very happy','bad','bad','very bad')

customerExperience_fct <-factor(customerExperience)
table(customerExperience_fct)
levels = c("very bad","bad","satisfied ","happy","very happy")
customerExperience_fct_ordered<-
    factor(customerExperience_fct, 
    levels = c("very bad","bad","satisfied ","happy","very happy"),
    ordered = T                                  )
customerExperience_fct_ordered[[1]]<"happy"
customerExperience_fct_ordered[[1]]>"happy"

```