In R, how can I overwrite the first values of a long vector with values obtained from a file, where the file contains possibly fewer values?
Example:
# fill with n=100 values
vec1 <- runif(100)
# read m values, where m <= n
vec2 <- scan("myfile", sep="\n")
# now want to set the first m values of vec1
# to the values in vec2
I could walk through vec2 and copy the values into vec1, but I think there should be a more efficient way?
R> set.seed(1)
R> vec1 <- runif(100)
R> vec2 <- 1:20
R> vec1[1:length(vec2)] <- vec2
R> vec1
[1] 1.00000 2.00000 3.00000 4.00000 5.00000 6.00000 7.00000 8.00000
[9] 9.00000 10.00000 11.00000 12.00000 13.00000 14.00000 15.00000 16.00000
[17] 17.00000 18.00000 19.00000 20.00000 0.93471 0.21214 0.65167 0.12556
[25] 0.26722 0.38611 0.01339 0.38239 0.86969 0.34035 0.48208 0.59957
[33] 0.49354 0.18622 0.82737 0.66847 0.79424 0.10794 0.72371 0.41127
[41] 0.82095 0.64706 0.78293 0.55304 0.52972 0.78936 0.02333 0.47723
[49] 0.73231 0.69273 0.47762 0.86121 0.43810 0.24480 0.07068 0.09947
[57] 0.31627 0.51863 0.66201 0.40683 0.91288 0.29360 0.45907 0.33239
[65] 0.65087 0.25802 0.47855 0.76631 0.08425 0.87532 0.33907 0.83944
[73] 0.34668 0.33377 0.47635 0.89220 0.86434 0.38999 0.77732 0.96062
[81] 0.43466 0.71251 0.39999 0.32535 0.75709 0.20269 0.71112 0.12169
[89] 0.24549 0.14330 0.23963 0.05893 0.64229 0.87627 0.77891 0.79731
[97] 0.45527 0.41008 0.81087 0.60493