lubridate.Rmd

---
title: "lubridate"
date: 2017-03-03T13:46:45+01:00
draft: false
image: "lubridate.jpg"
categories: ["R"]
tags: ["lubridate", "R"]
---

## 1. What is lubridate and why would you use it?

* it's an R package that makes working with dates easy;

* because in basic, no-frills R working with dates may be a little bit daunting

## 2. A few "Hello World" examples


Load the package
```{r, eval = FALSE}
library(lubridate)
```
```{r, echo = FALSE}
suppressPackageStartupMessages(library(lubridate))
```

Convert a string to class `Date`:
```{r}
# the base way
d <- as.Date("2017-03-03")
class(d)
# the lubridate way
d <- ymd("2017-03-03")
class(d)
```

Extract year, month and day
```{r}
year(d)
month(d)
day(d)
```

You can also modify the date on the fly:
```{r}
year(d) <- 1410
month(d) <- 7
day(d) <- 15
print(d)
class(d)
```

Now, analogical to python's `datetime.now()`:
```{r}
# the base way
n <- Sys.time()
# the lubridate way
n <- now()
```

Extracting hour, minute and second
```{r}
hour(n)
minute(n)
second(n)
```

Days of the week
```{r}
wday(d)  # numbering starts from Sunday! you can adjust it, read ?wday
```

Adding / subtracting dates:
```{r}
print(d)
d + years(1)  # yearS - plural form
d - months(2)
```