--- a/r.rst Sun Feb 28 01:00:06 2016 +0200
+++ b/r.rst Sun Feb 28 14:10:07 2016 +0200
@@ -19,17 +19,24 @@
Brief info about any object::
typeof(str)
+ class(str)
+ unclass(str)
str(c(1, 2))
str(summary)
-Brief info about vectors and matrixes::
+Column names of datasets::
+
+ names(...)
+ names(list(colA=1, colB=2))
+
+Column/row names of matrixes::
- summary(1:8)
- summary(matrix(1:20, 4, 5))
+ colnames(matrix(...))
+ rownames(matrix(...))
-Brief info on datasets and matrixes::
+List objects in global context: ``ls()``.
- names(list(colA=1, colB=2))
+Objext size in memory: ``object.site(1:2)``
Debugging
=========
@@ -82,6 +89,9 @@
rbinom(n, size, prob)
rpois(n, lambda)
runif(n, min = 0, max = 1)
+ rexp
+ rchisq
+ rgamma
In order to generate predictable sequences use::
@@ -94,3 +104,47 @@
sample(1:10, 10) ## permutation!!
sample(1:10, 100, replace=TRUE)
+
+Looping over data
+=================
+
+``lapply`` iterate over data and return list of function application::
+
+ lapply(1:5, function(x) x^2)
+ lapply(matrix(rnorm(20*10),20,10), mean)
+
+Exploring data
+==============
+
+Check `Inspecting objects`_ section.
+
+Investigating unique values::
+
+ sapply(data, unique)
+ sapply(data$col, unique)
+ sapply(data[,c("col1","col2")], unique)
+ sapply(data[,5:10], unique)
+
+ table(data$col)
+
+ tapply(data$what, data$by, unique)
+ tapply(data$what, data$by, summary)
+ tapply(data$what, data$by, range)
+ tapply(data$what, data$by, mean)
+ tapply(data$what, data$by, sd)
+
+Brief info about vectors and matrixes::
+
+ summary(1:8)
+ summary(matrix(1:20, 4, 5))
+
+Simple plots::
+
+ i<-1:100
+ x<-i/10
+ y<-x^2
+ plot(x,y)
+
+ hist(rpois(100,10))
+ hist(rpois(100,10),breaks=20)
+