Dear R-help forum members,
Suppose I have a data-frame having two variables and single data for each of
them, as described below.
variable_1 variable_2
10 20
I have written a function, say, 'fun' which uses input 10 and 20 and gives me
desired result.
fun = function(X, Y)
{
X + Y #( I am just giving an example of process. Actual
process is
quite different.)
}
result = fun(variable_1[1], variable_2[1]) # Thus, i should be getting answer
30 which I am storing in say 'ans1.csv'
# ____________________________________________________________________
# My problem
Suppose instead of having above dataframe having single data for variable 1 and
variable 2, I have following data as
variable_1 variable_2
10 20
40 30
3 11
I need to run the function 'fun' for each pair of values taken by variable_1
and variable_2 separately. Also, the results (= 30, 70 and 14) obtained for
each of above pairs should be stored in different csv files, say "ans1.csv",
"ans2.csv" and "ans3.csv" respectively which I can use for further analysis.
(In reality each of these output files will consists of 1000 records).
As I had mentioned in my earlier mail, I am new to R and I think I
should be using apply or sapply or tapply etc., which I have tried but I am
not able to proceed further as I am not able to understand it properly.
It will be a great help to me if I receive the guidance w.r.t
(a) how do I tackle above problem i.e. how do I apply the function to a table
so that it will generate different csv files pertaining to pair of values "10
and 20", "40 and 30" and "3 and 11";
(b) I am not that sharp to understand the programming aspects of R taht easily,
though I am really keen to learn R, so I will be highly obliged if someone
helps me understand with some simple examples as to how "apply", "supply",
"tapply", "mapply" etc can be used?
I am sure this will go a long way in helping the new learners like me to
undesrtand the proper use of these wonderful commands.
I hope I am able to put forward my problem properly.
Thanking all in advance for the anticipated guidance
Amelia
Vettori, Auckland
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