I am writing some code for a statistics class and I don't know how I can compare two values in R.
Basically I want the programm to give me a statment like:
Z<A
Z>A
Z=A
etc.
Z and A are definied by other operations in the code. How do I get R to do this?
Related
I am trying to get the following done: I have two columns (lets say codeA and codeB) in a dataframe A and want to compare these characters to a column (codeC) of another dataframe B. The codeA and codeB are the same in most cases, if they are not the same, the code (A/B) that matches codeC should be written in a new column.
So far I did not manage to achieve this result in combining if and for loops in R. Can someone help me?
Gretly appreciated!
I tried to code it using if and for loop but did not get the result needed.
I am a Stata user and I have to use R for a project. I want to repeat a line of code for different values. In other words, I want to avoid repeating these lines 15 times:
M20<-as.data.frame(cbind(c(1:20),exclusivity(model20), semanticCoherence(model=model20, docs), "Mod20"))
M21<-as.data.frame(cbind(c(1:21),exclusivity(model21), semanticCoherence(model=model21, docs), "Mod21"))
If I follow the logic of Stata, I would write something like this:
forvalues i=20(1)35 {
M`i'<- as.data.frame(cbind(c(1:`i'),exclusivity(model`i'), semanticCoherence(model=model`i', docs), "Mod`i'"))
}
and Stata would understand that `i' should change each time, whether it's a number or part of the name of an object.
I can't figure out how I can replicate the same loop in R.
I appreciate your help
p.s. someone said my question is the same as this one. I don't see the similarity!
How to apply a function to a certain column for all the data frames in environment in R
I am trying to automate a process instead of individually compute PPCC values for a large number of test cases. The details of my functions do not matter (though for reference I'm using Lmomco), my issue is either putting this into a loop or somehow using plyr or apply to repeat over and over. I do not know how to automate the string. For example I have sorted data by "M" parameter:
testx.100cv1<-by(x.cv1$first_year,x.cv1$M,sort)
I then apply a function here:
testexp<-lapply(testx.100cv1,parexp)
Now I want to do something to each "M", where in the example below, M = 1.02. Right now, I am manually changing this value and then recomputing for every M (and I have a lot of them). I'm looking for a way to write this M value into a loop so it reads it automatically.
exp<-quaexp(plotpos,testexp$'1.02')
PPCCexp<-cor(exp,testx.100cv1$'1.02')
I want to compute PPCC values for many distributions, so without automating, this will take over my life for a week.
Thanks!
I am new to R and mostly working with old code written by someone else. And I am trying to create my own R functions.
I found some of the following code used for eigenvalue decomposition.
eigenMatrix = eigen(myMatrix)[[2]]
eigenVals = eigen(myMatrix)[[1]]
Here there is single function that can output 2 different data structures, being, a vector and a matrix depending of the value in the brackets.
When I search of functions with multiple outputs, they usually use lists to output multiple variables at once which does not work, possibly because of different types.
I don't understand why there are two setts of brackets and how the underlying function would work.
The posted code takes the eigen function, which returns a list with 2 values.
Then the [[]] are use to extract the first and second items from the list.
The [[]] is needed to return the underlying structure, and is better explained here: How to Correctly Use Lists in R?
Also, since the eigen function is run twice the code in the question is inefficient.
resultList = eigen(myMatrix)
eigenMatrix = resultList[[2]]
eigenVals = resultList[[1]]
This code is better since eigen is run only once and saves the result of the function as a list and then reads the values from the list.
For the function itself can be coaded as any function with multiple outputs such as here: https://stat.ethz.ch/pipermail/r-help/2007-March/126851.html or here: How to assign from a function with multiple outputs?
The list values can hold any structure and [[]] can be used to return the underlying structure of each value.
So I'm trying to manipulate a simple Qualtrics CSV, and I want to use colSums on certain columns of data, given a certain filter.
For example: within the .csv file called data, I want to get the sum of a few columns, and print them with certain labels (say choice1, choice2 etc). That is easy enough by itself:
firstqn<-data.frame(choice1=data$Q7_2,choice2=data$Q7_3,choice3=data$Q7_4);
secondqn<-data.frame(choice1=data$Q8_6,choice2=data$Q8_7,choice3=data$Q8_8)
print colSums(firstqn); print colSums(secondqn)
The problem comes when I want to repeat the above steps with different filters, - say, only the rows where gender==2.
The only way I know how is to create a new dataset data2 and replace data$ with data2$ in every line of the above code, such as:
data2<-(data[data$Q2==2,])
firstqn<-data.frame(choice1=data2$Q7_2,choice2=data2$Q7_3,choice3=data2$Q7_4);
however i have 6 choices for each of 5 questions and am planning to apply about 5-10 different filters, and I don't relish the thought of copy/pasting data2 and `data3' etc hundreds of times.
So my question is: Is there any way of getting R to reference data by default without using data$ in front of every variable name?
I can probably use attach() to achieve this, but i really don't want to:
data2<-(data[data$Q2==2,])
attach(data2)
firstqn<-data.frame(choice1=Q7_2,choice2=Q7_3,choice3=Q7_4);
detach(data2)
is there a command like attach() that would allow me to avoid using data$ in front of every variable, for a specified amount of code? Then whenever I wanted to create a new filter, I could just copy/paste the same code and change the first command (defining a new dataset).
I guess I'm looking for some command like with(data2, *insert multiple commands here*)
Alternatively, if anyone has a better way to do the above in an entirely different way please enlighten me - i'm not very proficient at R (yet).