Chapter 6 Data Frames

Generally researchers are interested in working with data frames rather than individual vectors. Data frames can be read into R or created within R.

6.1 loading in data frames from a package

For this workshop we will be working with data from the Lahmen data base. This can be downloaded as a package using the instructions from above.

#install.packages("Lahmen")
library(Lahman)
data(Batting)
# Allows you to see the first 6 hitters
head(Batting)

##    playerID yearID stint teamID lgID  G  AB  R  H X2B X3B HR RBI SB CS BB SO IBB HBP SH SF GIDP
## 1 abercda01   1871     1    TRO   NA  1   4  0  0   0   0  0   0  0  0  0  0  NA  NA NA NA    0
## 2  addybo01   1871     1    RC1   NA 25 118 30 32   6   0  0  13  8  1  4  0  NA  NA NA NA    0
## 3 allisar01   1871     1    CL1   NA 29 137 28 40   4   5  0  19  3  1  2  5  NA  NA NA NA    1
## 4 allisdo01   1871     1    WS3   NA 27 133 28 44  10   2  2  27  1  1  0  2  NA  NA NA NA    0
## 5 ansonca01   1871     1    RC1   NA 25 120 29 39  11   3  0  16  6  2  2  1  NA  NA NA NA    0
## 6 armstbo01   1871     1    FW1   NA 12  49  9 11   2   1  0   5  0  1  0  1  NA  NA NA NA    0

6.2 Saving CSV files.

First you want to find your directory.

getwd()

## [1] "C:/Users/Owner/Documents/Introduction2R"

When you save a file it will be saved to this directory. You can save a csv file with the following code.

You can save a csv file with the following code.

## Save CSV File
write.csv(Batting, "battingexample.csv")


# in data frame
Batting <- read.csv("battingexample.csv")

6.3 Creating data frames in R

You can also create data frames within R. Here we are creating a data frame with hits and at bats for different players.

# create player 
player <- c("Player01", "Player02", "Player03", "Player04","Player05")
# Create Vector of Hits
hits <- c(3,1,0,2,4)
# Create Vector of At Bats
at_bats <- c(4,4,3,5,4)
# Create full data frame
hits_data_frame <- data.frame(PlayerID = player,
                                 Hits=hits,
                                 AtBats = at_bats)
hits_data_frame

##   PlayerID Hits AtBats
## 1 Player01    3      4
## 2 Player02    1      4
## 3 Player03    0      3
## 4 Player04    2      5
## 5 Player05    4      4

Note: Every vector used in the data frame must be of equal length.

6.3.1 Challenge

Create a data frame within R which stores information about 5 teams. The first column has team name, second column has wins, and the third column has losses. Team name and win/losses can be made up. Store the data with the name step_1. Save this data fram as a .csv file and then upload the saved data stored with the name step_2.