feat(guide):Added data frame guide article to R (#35845)

* feat:Added guide article for R

* Start feat/add-guide-article-for-r
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nCarol595
2019-06-28 03:15:30 -04:00
committed by Randell Dawson
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---
title: Data Frames
---
## Data Frames
A data frame is an object in R.
### Creating a Data Frame
You can create a data frame by combining vectors of the same length and using the function `data.frame`.
```r
a <- c(1 ,2, 3, 4, 5) #vector a
b <- c("H", "E", "L", "L", "O") #vector b
c <- c(TRUE, FALSE, FALSE, TRUE, FALSE) #vector c
df <- data.frame(a, b, c)
```
**NOTE**: You can also import data from a various data file such as a csv file to a data frame. See `Additional Resources` below for help with that.
### Adding Columns
To add a new column you can do `df$new_column_name`
#### Example
```r
df$product <- 2 * df[,1]
```
You can alternatively have a vector with them same amount of elements as a column in `df` as use the function `cbind` to combine it to `df`.
```r
product <- c(2, 4, 6, 8, 10)
df <- cbind(df, product)
```
Both ways will output the following table:
```
a b c product
1 1 H TRUE 2
2 2 E FALSE 4
3 3 L FALSE 6
4 4 L TRUE 8
5 5 O FALSE 10
```
### Removing Columns or Rows
You can remove a column or row by using `$` to specify a specific column name and making it `NULL`.
```r
df$b <- NULL #column b in df is deleted
```
Alternatively you can delete a specific row by using `df[row,]` or delete a specific row by using `df[,column]`.
#### Example
```r
df[1,] <- NULL #Deletes first row in df
df[,2] <- NULL #Deletes second column in df
```
### Sources
1. [DataMentor](https://www.datamentor.io/r-programming/data-frame/)
2. [ListenData](https://www.listendata.com/2015/06/r-keep-drop-columns-from-data-frame.html)
3. [PROGRAMMINGR](http://www.programmingr.com/examples/r-dataframe/add-delete-rows/)
### Additional Resources
1. [Data Frame Manipulation](http://www.cookbook-r.com/Manipulating_data/)
2. [Working with data in RStudio](http://paldhous.github.io/ucb/2016/dataviz/week7.html)
3. [Importing Data](https://www.datacamp.com/community/tutorials/r-data-import-tutorial)