**Strings**

- Formatting and Display of Strings
- Operations with Strings

**Formatting and Display of Strings**

Important commands regarding formatting and display are

print , format , cat and paste

print function prints its argument.

**Usage**

print ( )

print ( ) is a generic command that is available for every object class.

Examples:

> print (sqrt(2) )

[1] 1.414214

> print ( sqrt (2) , digits = 5)

[1] 1.4142

Format an R object for pretty printing.

**Usage**

format (x, ...)

x is any R object; typically numeric.

format (x, trim = FALSE, digits = NULL, nsmall = OL, justify = c("left" , "right" , "center" , "none") , width = NULL, . . .)

digits→shows how many significant digits are to be used.

nsmal→shows the minimum number of digits to the right of the decimal point.

justify→provides left-justified (the default), right-justified, or centered.

Examples:

> print (format ( 0.5, digits = 10, nsmall = 15) )

[1] "0.500000000000000"

**Matrix display**

> x <- matrix (nrow = 3, ncol = 2, data = 1:6, byrow = T)

> print (x)

[,1] [,2]

[1,] 1 2

[2,] 3 4

[3,] 5 6

Here, a matrix is displayed in the R command window.

One can specify the desired number of digits with the option digits.

The print function has a significant limitation that it prints only one object at a time.

Trying to print multiple items gives error message:

> print ("The zero occurs at", 2*pi, "radians.") Error in print.default("The zero occurs at",2*pi, "radians.") :

invalid 'quote' argument

The only way to print multiple items is to print them one at a time

> print ("The zero occurs at"); print (2*pi) ; print ("radians")

[1] "The zero occurs at"

[1] 6.283185

[1] "radians"

The cat function is an alternative to print that lets you combine multiple items into a continuous output.

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