r - Binning dates into decades, by column, in a matrix -

i have simulated matrix of dates generated probability function. each column represents single iteration.

i bin each run separately decades , dump them new matrix each column length of decades single run number dates binned decade.

i have done single vector of dates, not matrix:

"dates" vector of observed data representing when trees established in population

#find min , max decade mindecade <- min(dates)  maxdecade <- max(dates)   #create vector of decades  alldecades <- seq(mindecade, 2001, by=10)   #make empty vector of same length decade vector bin.vec <- rep(0,length(alldecades))   #populate bin.vec (empty vector) number of trees in each decade (i in 1:length(alldecades)) {                           bin.vec[i] <- length(which(dates==alldecades[i]))  }  

bin.vec:

0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 2 0 1 3 0 1 3 8 5 9 8 5 5 4 10 3 6 9 17 32 37 35 25 31 41 41 44 45 40 50 43 59 42 46 28 16 18 20 16 11 4 7 1

this need do, each separate column in matrix.

my matrix looks (it has 835 rows, used head() shorten it):

     1   2    3    4    5  1  1891 1791 1771 1741 1981     2  1881 1851 1941 1831 1841     3  1981 1861 1761 1781 1791     4  1911 1901 1941 1801 1801     5  1771 1751 1841 1751 1951     6  1821 1871 1821 1691 1851     7  1851 1851 1931 1921 1931     8  1921 1941 1601 1751 1861     9  1741 1761 1931 1791 1891     10 1751 1891 1951 1931 1901 

each column separate iteration of simulation (runs <- 10) . how can bin each column decades separately?

i answered on r-help morning, although data offered looked transpose of data give here:

> dates <- scan() 1:   1891 1791 1771 1741 1981     6:  1881 1851 1941 1831 1841     11:  1981 1861 1761 1781 1791     16:  1911 1901 1941 1801 1801     21:  1771 1751 1841 1751 1951     26:  1821 1871 1821 1691 1851     31:  1851 1851 1931 1921 1931     36:  1921 1941 1601 1751 1861     41:  1741 1761 1931 1791 1891     46:  1751 1891 1951 1931 1901 51:  read 50 items   dates <- matrix(dates, ncol=5, byrow=true)  apply( dates, 2, function(colm){                      1 + max(findinterval(colm, alldecades)) -                              min(findinterval(colm, alldecades) )                                 } ) #----------- #[1] 25 20 36 25 20 

in answer did note problem description ambiguous . if want matrix number of rows equal length of 'alldecades' use code:

 apply( dates, 2, function(colm) {                  alldec0 <- rep(0, length(alldecades))                 names(alldec0) <- 1:length(alldec0)                 alldec0[ as.numeric(names(table(findinterval(colm, alldecades))))] <-                             table(findinterval(colm, alldecades))                  return(alldec0)                   } )