formula

I'm trying to get my head around the use of the tilde operator, and associated functions. My 1st question is why does I() need to be used to specify arithmetic operators? For example, these 2 plots generate different results (the former having a straight line, and the latter the expected curve) x <- c(1:100) y <- seq(0.1,10,0.1) plot(y~x^3) plot(y~I(x^3)) further, both of the following plots also generate the expected result plot(x^3, y) plot(I(x^3), y) My second question is, perhaps the examples I've been using are too simple, but I don't understand where ~ should actually be used. The issue

Does anyone know of any formula for converting a light frequency to an RGB value? Here's a detailed explanation of the entire conversion process: http://www.fourmilab.ch/documents/specrend/ . Source code included! For lazy guys (like me), here is an implementation in java of the code found in @user151323 's answer (that is, just a simple translation from pascal code found in Spectra Lab Report ): static private double Gamma = 0.80; static private double IntensityMax = 255; /** Taken from Earl F. Glynn's web page: * <a href="http://www.efg2.com/Lab/ScienceAndEngineering/Spectra.htm">Spectra Lab

The following code does work how I need it to, but it's ugly, excessive or a number of other things. I've looked at formulas and attempted to write a few solutions, but I end up with a similar amount of statements. Is there a type of math formula that would benefit me in this instance or are 16 if statements acceptable? To explain the code, it's for a kind of simultaneous-turn-based game.. two players have four action buttons each and the results come from an array (0-3), but the variables 'one' & 'two' can be assigned anything if this helps. The result is, 0 = neither win, 1 = p1 wins, 2 = p2

I am not able to resolve the issue that when lm(sformula) is executed, it does not show the string that is assigned to sformula . I have a feeling it is generic way R handles argument of a function and not specific to linear regression. Below is the illustration of the issue through examples. Example 1, has the undesired output lm(formula = sformula) . The example 2 is the output I would like i.e., lm(formula = "y~x") . x <- 1:10 y <- x * runif(10) sformula <- "y~x" ## Example: 1 lm(sformula) ## Call: ## lm(formula = sformula) ## Example: 2 lm("y~x") ## Call: ## lm(formula = "y~x") How about

There seems to be a bug with Excel hyperlinks which are generated with a formula. I'm using Excel 2010. I have a spreadsheet with cells containing URLs, and my goal is to do the following two things: Turn these cells into hyperlinks. Create a keyboard shortcut to open these hyperlinks so I don't have to use the mouse. To do #1, initially I just used the function =HYPERLINK() . So, my URLs are in column A , and I used this formula to make hyperlinks in column B . To do #2, I created the following macro which should open the hyperlink with the keyboard shortcut Ctrl + H : Sub Open_Hyperlink() '

I haven't been able to find an answer to this question, largely because googling anything with a standalone letter (like "I") causes issues. What does the "I" do in a model like this? data(rock) lm(area~I(peri - mean(peri)), data = rock) Considering that the following does NOT work: lm(area ~ (peri - mean(peri)), data = rock) and that this does work: rock$peri - mean(rock$peri) Any key words on how to research this myself would also be very helpful. I isolates or insulates the contents of I( ... ) from the gaze of R's formula parsing code. It allows the standard R operators to work as they

I have table with data in the format below. Data I want the finished table to have the blank column to be populated like the highlighted one below. Finished Table So, I need a formula or VBA that will return and concatenate the headers of non-blank cells in each row. Use¹ the following as an array formula . =TEXTJOIN("-->", TRUE, IF(LEN(C3:I3), C$2:I$2, "")) Pre-Excel 2016 versions While you could just string together a series of IF statements, a cleaner alternate might be to write a user defined function (aka UDF). In a standard VBA module code sheet: Function udf_Stitch_Together(r As Range,