 Shuffle Toggle OnToggle Off
 Alphabetize Toggle OnToggle Off
 Front First Toggle OnToggle Off
 Both Sides Toggle OnToggle Off
 Read Toggle OnToggle Off
Reading...
How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
Up/Down arrow keys: Flip the card between the front and back.down keyup key
H key: Show hint (3rd side).h key
A key: Read text to speech.a key
Play button
Play button
46 Cards in this Set
 Front
 Back
Matrix (N * T) into Vector.

(i1)*T + t


Type of an object?

class(obj)


Eliminate the effect of class.

unclass(obj)


Levels of a factor?

levels(factor)


What is a data.frame?

A list made into a matrix.


Formating in C.

formatC(foo, digits=3)


Formating in C to obtain integers.

formatC(foo, format="d")


Intersection between two vectors.

intersect(vec1,vec2)


Belong to a set.

belong(element,set)
FALSE or TRUE 

Demonstration of plotting maths.

demo(plotmath)


Including mathematical formulaes.

expression()


Combingin maths and variables.

bquote()


Horizontal axis labels.

par(las=1)


Margin intervals.

par(mai=c(1,1,1,1))


Direction of par(mai=c(1,1,1,1))

bottom, left, top, right.


Order and apply an order.

o < order[vec]
order.vec < vec[o] 

Differences between two sets.

setdiff(v1,v2)


Select type of output in SCAN.

scan(foo.txt, what="character)


Add a grid to a graph.

grid(Number_Cells_X, Number_Cells_Y, lwd=2)


Pvalue from ANOVA object.

anova$p


Fvalue from ANOVA object.

anova$F


1:3  2

c(1,0,1)


1:3*2

c(2,4,6)


Close R.

q()


Fit a linear model with DESIGN matrix.

lm.fit(X[n*p], y[n])


Fixed and Random Coefficients in LME.

model$coefficients


Factor to numeric

as.numeric(as.vector(factor))


Is a missing value?

is.na(value)


Max removing missing values.

max(vec, na.rm=TRUE)


Random/Fixed effects from a model.

mod$coefficients


Bash within R.

system("mkdir foo")


Set working directory.

setwd()


Suppress a letter in a string.

strsplit( "foo\", "\")


Write entries in one single column.

write(foo, foo.txt, ncolumns=1)


Matrix Product.

A %*% B


xAx

x %*% A %*% x


Matrix Inverse

solve(A)


xA^{1}x

x %*% solve(A,x)


Permission problem when installing new package.

chown 777 R R


Difference between order() and rank().

x[order(x)] is equivalent to sort(x).
rank(x) is just the ranks. 

gedelete

gedelete


Difference between && and &

&& apply to vectors of length 1.
& apply elementwise to vectors. 

Difference between  and 

 apply to vectors of length 1.
 apply elementwise to vectors. 

Syntax for while.

while (condition) expr


Maximum likelihood estimation.

mle(loglik)


Plot Time series.

plot(as.ts(mat))
