4. File System and Simple IO

Working directory:

> getwd()
[1] "C:/Users/Shailesh"

Changing working directory:

> setwd('..')
> getwd()
[1] "C:/Users"
> setwd('shailesh')
> getwd()
[1] "C:/Users/shailesh"

4.1. Printing

printing a vector:

> x <-10
> print(x)
[1] 10

> print(1:3)
[1] 1 2 3

Printing data in a loop:

> for (month in month.abb[1:4]){print(month)}
[1] "Jan"
[1] "Feb"
[1] "Mar"
[1] "Apr"

Printing factors:

> fruits = c("apple", "banana", "pear", "watermelon")
> fruit_list <- sample(fruits, 20, replace=TRUE)
> fruit_factors <- factor(fruit_list, levels=fruits)
> fruit_factors
 [1] banana     apple      apple      pear       apple      apple      apple      banana     apple
[10] watermelon banana     watermelon apple      banana     apple      pear       banana     banana
[19] banana     pear
Levels: apple banana pear watermelon
> print(fruit_factors)
 [1] banana     apple      apple      pear       apple      apple      apple      banana     apple
[10] watermelon banana     watermelon apple      banana     apple      pear       banana     banana
[19] banana     pear
Levels: apple banana pear watermelon

Factors can be printed with quotes:

> print(fruit_factors, quote=TRUE)
 [1] "banana"     "apple"      "apple"      "pear"       "apple"      "apple"      "apple"      "banana"
 [9] "apple"      "watermelon" "banana"     "watermelon" "apple"      "banana"     "apple"      "pear"
[17] "banana"     "banana"     "banana"     "pear"
Levels: "apple" "banana" "pear" "watermelon"

Skipping the levels while printing:

> print(fruit_factors, quote=TRUE, max.levels = 0)
 [1] "banana"     "apple"      "apple"      "pear"       "apple"      "apple"      "apple"      "banana"
 [9] "apple"      "watermelon" "banana"     "watermelon" "apple"      "banana"     "apple"      "pear"
[17] "banana"     "banana"     "banana"     "pear"

Controlling the number of digits in floating point numbers:

> print(pi)
[1] 3.141593
> print(pi, digits=15)
[1] 3.14159265358979
> print(pi, digits=4)
[1] 3.142