Augix Guohua XU's List: bioinformatics

option(width=40)

outer(1:4,1:4,"*")

p = function(...) paste(...,sep='')

replicate(10, sample(1:6,1))

image(matrix(1:63,7))

ifelse()

<<- # only affect one level up

repeat and break

sapply() works for a vector or matrix if appropriate.

sapply() returns a list if lengthes are different.

sapply(x, func, args) # you can give additional arguments to sapply function

order()

system.time()

args() # instead of ?, we use args to only see the args the function taks.

cumsum # accumulated sum.

rbinom, dbinom, pbinom, qbinom

pbinom(5, 20, prob=0.5) # what is the probability to see 5 heads.

nchar() # number of characters in a string.

ppois(x,...,lower.tail=F) # lower.tail=F give probability of seen x or > x.

rexp # how long do you need to wait till you see the next one.

rhyper #

lapply(pop,sample,rep=T) # pop could be a list with items with different lengthes.

plot(type='n') # plot blank

browser() # debug. command in browser environment: n, c, Q

debug() # put a browser() line at the beginning of the function.

traceback() # trace back the error

options(error=recover) # go back inside the function with error.

methods(plot) # methods of plot for different kinds of objects.

# print and plot function depends on the class of objects.

rowSums(), colSums(), rowMeans(), colMeans() #

xor() # logical switch