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Zhuo Yao, Ph.D.

Professional Website of Dr. Zhuo Yao
Zhuo Yao, Ph.D.
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Category: R

R

R Programming/Text Processing

construction supervison 11/03/2013

http://en.wikibooks.org/wiki/R_Programming/Text_Processing   This page includes all the material you need to deal with strings in R. The section on regular expressions may be useful to…

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R

R-substr, substring

construction supervison 11/03/2013

Retrieve or replace a substring of a character string via the substr and substringfunctions. Additionally, these functions can be used to overwrite a part of a character string.…

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R

Writing a for-loop in R

construction supervison 07/15/2013

by Patrick on 23 March, 2013 in Patrick’s Ponderables There may be no R topic that is more controversial than the humble for-loop. And, to top it off, good help…

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R

Plotting a 3D surface plot with contour map overlay, using R

construction supervison 07/02/2013

I have a 3-tuple data set (X,Y,Z points) that I want to plot using R. I want to create a surface plot from the data,…

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R

Reading in data from an external file

construction supervison 07/01/2013

Reading in data from an external file The data sets: test.txt, cars.txt, test_missing.txt, test_missing_comma.txt, test_fixed.txt, scan.txt, 1. Reading in data from the console using the scan function For very small data vectors it…

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R

Summary statistics by two or more factor variables

construction supervison 06/09/2013

How about this, still using tapply()? It’s more versatile than you knew! with(mtcars, tapply(mpg, list(cyl, gear), sum)) # three four five # four 21.5 215.4 56.4…

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R

Factors in R

construction supervison 06/09/2013

Factors in R Conceptually, factors are variables in R which take on a limited number of different values; such variables are often refered to as…

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R

Frequencies and Crosstabs

construction supervison 06/09/2013

This section describes the creation of frequency and contingency tables from categorical variables, along with tests of independence, measures of association, and methods for graphically…

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R

R- Table Function

construction supervison 06/09/2013

R Tutorial Cyclismo.org Two Way Tables Here we look at some examples of how to work with two way tables. We assume that you can enter…

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R

Open Access .mdb Files with RODBC

construction supervison 05/14/2013

Getting data into R can be done by reading colon separated files (.csv) via the read.table() function. It is also possible to access databases directly…

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