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# Data Structure: Vector (Elements with same data type)
# concatenate or combine
st=c("s1","s2","s3","s4")
marks=c(20.5,25,27,21)
marks
## [1] 20.5 25.0 27.0 21.0
# Quiz 1:How many digits R displays after decimal by default?
# Create sequence of integer - increment by 1
1:10
## [1] 1 2 3 4 5 6 7 8 9 10
# Create sequence of integer - arbitrary increment
seq(1,20,.2)
## [1] 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8
## [16] 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8
## [31] 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.4 8.6 8.8 9.0 9.2 9.4 9.6 9.8
## [46] 10.0 10.2 10.4 10.6 10.8 11.0 11.2 11.4 11.6 11.8 12.0 12.2 12.4 12.6 12.8
## [61] 13.0 13.2 13.4 13.6 13.8 14.0 14.2 14.4 14.6 14.8 15.0 15.2 15.4 15.6 15.8
## [76] 16.0 16.2 16.4 16.6 16.8 17.0 17.2 17.4 17.6 17.8 18.0 18.2 18.4 18.6 18.8
## [91] 19.0 19.2 19.4 19.6 19.8 20.0
# replicate the values in a vector
rep(c("A","B"),5)
## [1] "A" "B" "A" "B" "A" "B" "A" "B" "A" "B"
# assignment
# Elements of a vector - One element, multiple elements
st[3]
## [1] "s3"
# Boolean vector
# Deselecting the vector elements
st[-3]
## [1] "s1" "s2" "s4"
# Types of Vector : numeric,integer,complex, character, logical, factor
# Factor denotes the categorical variable in the data
sub=c("Phy","Phy","Hist","Hist")
subFactor=factor(sub)
subFactor
## [1] Phy Phy Hist Hist
## Levels: Hist Phy
# Modification of type of a vector
marks=as.character(marks)
# Length of a vector.
length(st)
## [1] 4
# Quiz 2: Use length function to find out the last element of a vector.
# Numerical Operator - Vector Addition, subtraction, Multiplication,
x = c(2.1, 5, -4, 1)
y = c(0, -7, 1, 1 / 4)
x
## [1] 2.1 5.0 -4.0 1.0
y
## [1] 0.00 -7.00 1.00 0.25
x+y
## [1] 2.10 -2.00 -3.00 1.25
x*y
## [1] 0.00 -35.00 -4.00 0.25
x*y
## [1] 0.00 -35.00 -4.00 0.25
# Minimum, Maximum, sum, product, cumulative sum of a vector
min(x)
## [1] -4
max(x)
## [1] 5
sum(x)
## [1] 4.1
prod(x)
## [1] -42
cumsum(x)
## [1] 2.1 7.1 3.1 4.1
cumprod(x)
## [1] 2.1 10.5 -42.0 -42.0
# Logical Operator
# not, and ,or ,comparison, equality
# paste function for character vectors
# Ordering and rank of vectors
# Matrix
# List
# dataframe
# Assign Car object into a new data frame
# nrow,ncol, dim, dimnames, names
# Subset of data frame
# Keep all the variables fro 3rd observation
# keep the 2nd variables for all observations
# keep observations 1 to 5, 12 and 15
# remove observations 10 to 20.
# keep the last observation using nrow