Printing in R

---

print()

> x <- 'Hello world!'
> print(x)
[1] "Hello world!"

quote

If quote is set to FALSE then the quotation marks won’t be printed-

> print(x, quote= F)
[1] Hello world!

digits

to print values for specific number of digits-

> print(c(pi,4.783))
[1] 3.141593 4.783000
> print(c(pi,4.783),digits = 15)
[1] 3.14159265358979 4.78300000000000

na.print

To show something else in place of NA-

> vac <- c(1,3,5, NA, 6, NA, 47, NA)
> print(vac)
[1]  1  3  5 NA  6 NA 47 NA
> print(vac, na.print="0") 
[1]  1  3  5  0  6  0 47  0
> print(vac, na.print="Empty") 
[1]     1     3     5 Empty     6 Empty    47 Empty

print.gap

To change the gap between the outputs-

> vac <- c(1,3,5,6,47)
> print(vac)
[1]  1  3  5  6 47
> print(vac, print.gap= 4)
[1]     1     3     5     6    47

right

To print right aligned outputs-

> de<- c('Himel','ahsanhimel@email.com')
> print(de)
[1] "Himel"                "ahsanhimel@email.com"
> print(de, right= T)
[1]                "Himel" "ahsanhimel@email.com"

max

To define how many values to show-

> s<- c(1:50)
> print(s)
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
[26] 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
> print(s, max=10)
 [1]  1  2  3  4  5  6  7  8  9 10
 [ reached getOption("max.print") -- omitted 40 entries ]
> print(s, max=5)
[1] 1 2 3 4 5
 [ reached getOption("max.print") -- omitted 45 entries ]

row.names

To hide the row numbers set row.names to FALSE-

> sel<-c(1:3)
> names<-c('Himel','Elias','Tonmoy')
> df<- data.frame(sel,names)
> print(df)
  sel  names
1   1  Himel
2   2  Elias
3   3 Tonmoy
> print(df, row.names=F)
 sel  names
   1  Himel
   2  Elias
   3 Tonmoy

---

noquote()

nonquote() is equivalent to using quote=F in print()-

> str<- "programming with data is fun"
> print(str)
[1] "programming with data is fun"
> noquote(str)
[1] programming with data is fun

---

cat()

"" needs to be used in cat() so that the next object prints on the next line-

> str<- "programming with data is fun"
> for (i in 1:3){
+   cat(str)
+ }
programming with data is funprogramming with data is funprogramming with data is fun
> for (i in 1:3){
+   cat(str,"\n")
+   }
programming with data is fun 
programming with data is fun 
programming with data is fun 

Also the outcome doesn’t show [1] meaning that if it is assigned to any variable then it will print NULL instead of printing out the object-

> a <- print("Print example")
[1] "Print example"
> b <- cat("Cat example")
Cat example
> a
[1] "Print example"
> b  # will show NULL
NULL

fill

The argument fill is either a logical variable or a positive number.
The default value is FALSE.
If TRUE, line breaks are set with “\n” or a break in a quoted string.
If fill is a positive number, the number is used to set the width.

> words<- c('a','b','d','e')
> for (i in 1:3){
+ cat(words, fill=F)
+ }
a b d ea b d ea b d e
> for (i in 1:3){
+ cat(words, fill=T)
+ }
a b d e
a b d e
a b d e
> cat(words, fill=1)
a 
b 
d 
e
> cat(words, fill=6)
a b d 
e
> cat(words, fill=4)
a b 
d e

sep

> cat(month.name[1:4],"\n")
January February March April 
> cat(month.name[1:4], sep= ' > ')
January > February > March > April

An application of cat

> n<-c(-10,0,10,100)
> for (i in n){
+   R<-round(rnorm(10,i,1))
+   cat('When Mean is',i,'\nRandom Numbers: ',R,'\n', fill=T)}
When Mean is -10 
Random Numbers:  -9 -9 -10 -9 -10 -11 -9 -11 -10 -10 

When Mean is 0 
Random Numbers:  -1 -1 0 0 1 0 -1 1 0 1 

When Mean is 10 
Random Numbers:  11 10 9 10 10 11 11 10 10 9 

When Mean is 100 
Random Numbers:  99 100 100 98 100 100 100 99 99 100 

---

paste()

It converts its arguments to character strings via as.character

> paste('Himel', 4+5, 'Durjoy', 'Rafi')   # by default sep=' '
[1] "Himel 9 Durjoy Rafi"
> paste(c(1:5, 4, 99))
[1] "1"  "2"  "3"  "4"  "5"  "4"  "99"

paste0 is equivalent to paste(.., sep=’’)

> paste0('Himel', 4+5,'Durjoy', 'Rafi')
[1] "Himel9DurjoyRafi"

sep

> paste('Himel', 'Durjoy', 'Rafi', sep=', ')
[1] "Himel, Durjoy, Rafi"
> paste(1:3,'YES','NO', sep=' - ')
[1] "1 - YES - NO" "2 - YES - NO" "3 - YES - NO"

collapse

> paste(c(1:5, 4, 99), collapse=', ')
[1] "1, 2, 3, 4, 5, 4, 99"

collapse vs sep

> paste(c(1:5, 4, 99), c('not','done'), collapse=', ')
[1] "1 not, 2 done, 3 not, 4 done, 5 not, 4 done, 99 not"
> paste(c(1:5, 4, 99), c('not','done'), sep=', ')
[1] "1, not"  "2, done" "3, not"  "4, done" "5, not"  "4, done" "99, not"

Using paste inside print()

> print(1+1,8+8,5-2)
[1] 2
> print(paste(1+1,8+8,5-2))
[1] "2 16 3"

---

format()

> a <- seq(1,12000,900)
> format(a)
 [1] "    1" "  901" " 1801" " 2701" " 3601" " 4501" " 5401" " 6301" " 7201"
[10] " 8101" " 9001" " 9901" "10801" "11701"

trim

> format(a, trim=T)
 [1] "1"     "901"   "1801"  "2701"  "3601"  "4501"  "5401"  "6301"  "7201" 
[10] "8101"  "9001"  "9901"  "10801" "11701"

digits

> b <- c(1.3,1.43,pi)
> format(b)
[1] "1.300000" "1.430000" "3.141593"
> format(b, digits=3)
[1] "1.30" "1.43" "3.14"
> format(b, digits=12)
[1] "1.30000000000" "1.43000000000" "3.14159265359"

nsmall

To suggest how many decimal places to show-

> b <- c(1.3,1.43,1.784)
> format(b) 
[1] "1.300" "1.430" "1.784"
> format(b, nsmall=5)
[1] "1.30000" "1.43000" "1.78400"

It cannot round the values-

> format(b, nsmall=1)
[1] "1.300" "1.430" "1.784"

width

It suggests how long the total character string should be-

> print(b)
[1] 1.300 1.430 1.784
> format(b, width=7)
[1] "  1.300" "  1.430" "  1.784"

Like nsmall, it cannot cut any values-

> format(b, width=1)
[1] "1.300" "1.430" "1.784"

justify

> d <- c("a","b","c","drunk")
> format(d, justify = "right") 
[1] "    a" "    b" "    c" "drunk"
> format(d, justify = "centre") 
[1] "  a  " "  b  " "  c  " "drunk"

Combining with cat we can display it in a more convenient way

> cat(format(d, justify = 'right'), fill=1,"\n")
    a 
    b 
    c 
drunk 
> cat(format(d, justify = 'centre'), fill=1,"\n")
  a   
  b   
  c   
drunk 
> cat(format(d, justify = 'left'), fill=1,"\n")
a     
b     
c     
drunk 

---

sprintf()

For C like printing function-

> a <- 12; b <- pi; c <- "String";
> sprintf("%g and %.4f are not %s",a,b,c)
[1] "12 and 3.1416 are not String"