Hi all,
I am new to both programming and R. While some components of R I've found
easy to navigate (R seems to be the best software in terms of a
self-teaching program and I've enjoyed learning it), I've really been
struggling to understand how to code for-loops, even in tutorials. For
example, one I've seen within a tutorial is
∑25 =1 ^2
sum <- 0
for(i in 1:25)
sum <- sum + i^2
sum
but this example doesn't fit into using the assignment operator and then
creating loops from there, which I think I would better understand (if this
is possible to do). Other examples I have found also seem very complex.
I was hoping to share a scenario in which a for-loop would be incredibly
helpful for the analyses I am running so that I may better understand how to
write a loop going forward.
I have a huge data set ("studydata") composed of rows of categorical
variables and columns of continuous variables. The data can be organized
into those 3 categorical variables-- let's call them PatientGroup1
PatientGroup2 and ControlGroup. Then there are over 30 measured continuous
variables I need to run t.tests on (let's say three of the variables, for
example, are A, B, and C). so that it looks like this:
A B C ...D,E,F,etc.
PatientGroup1 4 6 8
PatientGroup2 5 7 9
ControlGroup 10 15 20
*repeats*
I've managed to go ahead and assign the values of each variable to the
respective categorical variable using the assignment operator so that I have
"PatientGroup1" "PatientGroup2" and "ControlGroup." I know how to run a
t.test by setting up the following code (though it may be amateur):
Variable_A_PatientGroup1=PatientGroup1$'A'
Variable_A_PatientGroup2=PatientGroup2$'A'
t.test(Variable_A_PatientGroup1, Variable_A_PatientGroup2)
However, if I wanted to create a loop, so that this same code runs for
variables B,C, etc. Is that feasible? Or is there another easier method to
implement? I appreciate any feedback and apologize in advance for my amateur
question.
I am new to both programming and R. While some components of R I've found
easy to navigate (R seems to be the best software in terms of a
self-teaching program and I've enjoyed learning it), I've really been
struggling to understand how to code for-loops, even in tutorials. For
example, one I've seen within a tutorial is
∑25 =1 ^2
sum <- 0
for(i in 1:25)
sum <- sum + i^2
sum
but this example doesn't fit into using the assignment operator and then
creating loops from there, which I think I would better understand (if this
is possible to do). Other examples I have found also seem very complex.
I was hoping to share a scenario in which a for-loop would be incredibly
helpful for the analyses I am running so that I may better understand how to
write a loop going forward.
I have a huge data set ("studydata") composed of rows of categorical
variables and columns of continuous variables. The data can be organized
into those 3 categorical variables-- let's call them PatientGroup1
PatientGroup2 and ControlGroup. Then there are over 30 measured continuous
variables I need to run t.tests on (let's say three of the variables, for
example, are A, B, and C). so that it looks like this:
A B C ...D,E,F,etc.
PatientGroup1 4 6 8
PatientGroup2 5 7 9
ControlGroup 10 15 20
*repeats*
I've managed to go ahead and assign the values of each variable to the
respective categorical variable using the assignment operator so that I have
"PatientGroup1" "PatientGroup2" and "ControlGroup." I know how to run a
t.test by setting up the following code (though it may be amateur):
Variable_A_PatientGroup1=PatientGroup1$'A'
Variable_A_PatientGroup2=PatientGroup2$'A'
t.test(Variable_A_PatientGroup1, Variable_A_PatientGroup2)
However, if I wanted to create a loop, so that this same code runs for
variables B,C, etc. Is that feasible? Or is there another easier method to
implement? I appreciate any feedback and apologize in advance for my amateur
question.
