Category Archives: R/S-Plus

ggplot2 draw bar chart with error bars

Where I tried to generate a nice bar chart, I came across to the following post. It provides all the information I need. Very nice work! http://www.sthda.com/english/wiki/ggplot2-barplots-quick-start-guide-r-software-and-data-visualization R Graphics Cookbook also provides a lot of good examples. Some may be … Continue reading

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Dealing with Date in R language

In R there is a class called Date. If we want to get the components of a date variable or date string, we can use the following function to do it. toNumerics <- function(Date) { stopifnot(inherits(Date, c(“Date”, “POSIXt”))) day <- … Continue reading

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Search turning points in the trading history of a stock

Stock prices fluctuate everyday. It is impossible to pinpoint the bottom or peak of a stock. But by analyzing the trading history of a stock, we can figure a some unusual signals in the trading history of a stock. By … Continue reading

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Data Analysis of Field Experiments in Agriculture with R

I wrote a series of lectures about analyzing data from agricultural experiments with Minitab long time ago. Since then I learned using SAS and R to analyzing experimental data. In order to share my experiences in data management and analysis … Continue reading

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R import MySQL data tables

R language is free. Its functions are very powerful. It can be used to do all kinds of data analysis and plot drawing. I always use MySQL database to manage my data. R has the capability to read data from … Continue reading

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