Introduction to Functions in R

This video tutorial gives you an introduction to creating functions in R.

Category:

Education

Tags:

• Intro2functioninR

[off2themovies2]

Hi Tentenlaw, Here is an easy way to do that.

Suppose we call your dataset data1 which has 40 columns and 40 rows. To obtain the mean simply do the following:

mean( data1[ ,1:20] ) # This gives the mean for all data in columns 1 through 20.

mean( data1[ 1:20, 1:20]) # This gives the mean for all data in columns 1 through 20 and in rows 1 through 20.

Hope this helps.

[off2themovies2]

You will have to specify exactly what you mean by the Jacobi method. My guess is that it is probably already coded in R in one of the contributed packages. But if I knew what algorithm you are trying to use I could probably help.

[off2themovies2]

@insomnialu. Sure I can give you tips. But R is so vast you need to provide some idea of the types of tips you would like. One big tip is: Avoid using Loops. R does not do loops well. Sometimes you can't avoid a loop but if you can trick R into doing something without a loop your program will probably run much faster.

[off2themovies2]

@insomnialu I will work on a video showing how to do basic model selection in R. It may take me a few weeks to get to it.

[Tentenlaw]

Mr. Boone, I need some assistance please. I want to find the mean of a row between particular columns.

For example, say I have 40 columns and 40 rows. I want to find the mean of the data in row 1 from column 1-20. I know how to do this! I simply have to use the transpose command to switch the variables. However, I can only do it for one row at a time.

How can I find the mean for all the rows from column 1-20? My professor suggested "for loops". I don't know how to do that! Please help!

[fiorodmarcostarica]

hi, i need to program the jacobi method and i dont know how to put it in R language, could you help me?

[insomnialu]

@off2themovies2 oh, ok, sorry for the late reply. I really like ur videos and it helped me a lot. Also I am taking a R programming course now, I hope if you could give me some tips.

Thank you so much

[insomnialu]

Hi I really love ur video which helped have better proficiency in r. I am wondering if you could show us the method for model selection like forward and backward selection? Thank you very much....