How to calculate the average of a value in R in a loop -

i have dataset one:

date_a  date_b  type price 2345    2400       120 1115    1230    b    226 930     945     c    90 1050    1100       157 

and want print values type column values of date_a less date_b. part did following code:

for(i in 1:length(list)){       if(`date_a`[i]<`date_b`[i]){         print(type[i])       }     } 

this code works fine. want calculate total average of price column type values printed before type's date_a < date_b. thought of doing like:

for(i in 1:length(list)){   if(`date_a`[i]<`date_b`[i]){     print(type[i])     price_average[i] <- mean(price)   } 

however gives me total mean of whole dataset , want mean of price date_a < date_b. trying figure out how calculate using loops since practicing loops in r.

i'm not sure understand want. try this:

mean(price[date_a < date_b])

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