seq() {base}

seq() is a functions that generates regular sequences.

 seq.int() is a primitive which can be much faster but has a few restrictions.

 seq_along() and seq_len() are very fast primitives for two common cases.

seq(from = 1, to = 1, by = ((to - from)/(length.out - 1)),length.out = NULL, along.with = NULL, ...)

seq.int(from, to, by, length.out, along.with)

seq_along(along.with)

seq_len(length.out)

The parameters are:

 - from,to: starting and end values of the sequence

 - by: increment of the sequence

 - lenght.out: length of the sequence

 - along.with: take the length from the length of this argument

seq():

seq(10)

##  [1]  1  2  3  4  5  6  7  8  9 10

seq(1,10)

##  [1]  1  2  3  4  5  6  7  8  9 10

seq(from = 1, to = 15, by = 2)   #from 1 to 15 every second number

## [1]  1  3  5  7  9 11 13 15

seq(from = 1, to = 15, by = 3)   #from 1 to 15 every third  number

## [1]  1  4  7 10 13

seq(from = 1, to = 10, length.out = 5)  #from 1 to 10, with a total sequence length of 5 

## [1]  1.00  3.25  5.50  7.75 10.00

seq(from = 1, to = 10, length.out = 10) #from 1 to 10, with a total sequence length of 5

##  [1]  1  2  3  4  5  6  7  8  9 10

seq(from = 1, by = 2, length.out = 5) # creates a seq from 1 and every second number, with a total lenght 5 

## [1] 1 3 5 7 9

seq(from = 10, by = 3, length.out = 10) # creates a seq from 10 and every third number, with a total lenght 10 

##  [1] 10 13 16 19 22 25 28 31 34 37

#seq(from = 1, to = 15, by = 2,  length.out = 5)   --Error, too many arguments!

seq(along.with = c(1:10))

##  [1]  1  2  3  4  5  6  7  8  9 10

seq(along.with = c(11:20))

##  [1]  1  2  3  4  5  6  7  8  9 10

seq(11,20, along.with = c(1:10))

##  [1] 11 12 13 14 15 16 17 18 19 20

seq(11,20, along.with = c(1:10))

##  [1] 11 12 13 14 15 16 17 18 19 20

seq.int():

seq(11,20)

##  [1] 11 12 13 14 15 16 17 18 19 20

seq.int(11,20)    #same result

##  [1] 11 12 13 14 15 16 17 18 19 20

y = 12:34
y

##  [1] 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

#seq(y, length.out = 6)    -- Error, 'from' must be of length 1!
seq(12,34, length.out = 6)

## [1] 12.0 16.4 20.8 25.2 29.6 34.0

seq.int(y, length.out = 6) #different result

## [1] 12 13 14 15 16 17

seq_along():

seq_along() only uses one argument.

x = 1:4 ; y = 5:10 ; z = 10
x

## [1] 1 2 3 4

y

## [1]  5  6  7  8  9 10

z

## [1] 10

seq(x)

## [1] 1 2 3 4

seq(y)

## [1] 1 2 3 4 5 6

seq(z)

##  [1]  1  2  3  4  5  6  7  8  9 10

seq_along(x)

## [1] 1 2 3 4

seq_along(y)

## [1] 1 2 3 4 5 6

seq_along(z)

## [1] 1

#seq_along(1,20) --Error, 2 arguments passed to 'seq_along' which requires 1

seq_len():

seq_len() only uses one argument.

x

## [1] 1 2 3 4

y

## [1]  5  6  7  8  9 10

z

## [1] 10

seq(x)

## [1] 1 2 3 4

seq(y)

## [1] 1 2 3 4 5 6

seq(z)

##  [1]  1  2  3  4  5  6  7  8  9 10

seq_len(x) #seq_len only uses the first argument

## Warning in seq_len(x): first element used of 'length.out' argument

## [1] 1

seq_len(y) #seq_len only uses the first argument

## Warning in seq_len(y): first element used of 'length.out' argument

## [1] 1 2 3 4 5

seq_len(z) 

##  [1]  1  2  3  4  5  6  7  8  9 10

par(mfrow = c(1,3))
plot(seq(from = 1, to = 15, by = 2), type = 'b', col = 'brown')
plot(seq(from = 1, to = 15, length.out = 5), type = 'b', col = 'deeppink')
plot(seq(from = 1, by = 2, length.out = 6), type = 'b', col = 'orange')