---
layout: post
title: "RP: Week 1 Part 2"
description: ""
category: "r programming"
tags: []
---

####Factors

- labels
- levels

####Missing values

- NA
- NaN
- is.na()
- is.nan()
- NA values have a class too.
- NaN is NA
- NA is not NaN

####Data frames

- row.names
- read.table() or read.csv()
- data.matrix()

####Names

R objects can have names

names()

List elements can also have names

dimnames()

---
layout: post
title: "RP: Week 1 Part 2"
description: ""
category: "r programming"
tags: []
---

####Factors

- labels
- levels

####Missing values

- NA
- NaN
- is.na()
- is.nan()
- NA values have a class too.
- NaN is NA
- NA is not NaN

####Data frames

- row.names
- read.table() or read.csv()
- data.matrix()

####Names

R objects can have names

names()

List elements can also have names

dimnames()

###Subsetting

- []
- [[]]
- $

####Subsetting a Matrix

```drop = FALSE``` will result in a matrix
otherwise will result in a vector(in most case)

####Partial matching

    x<-list(aardvark=1:5)
    x$a #aardvark
    x[["a", exact = FALSE]]

####Reading and writing data

- dput: single object
- dump: multiple objects

Call it an end for today
Call it an end for today
