alexland

/**
  * returns a transformed list (of strings) of the
  * 1-to-100 integer list passed in such that:
  *   integers evenly divisible by 3 are replaced by "fizz"
  *   integers evenly divisible by 5 are replaced by "buzz"
  *   integers evenly divisible by both 3 & 5 are replaced by "fizzbuz"
  *   all other integers are replaced by their string representation
  * */
def f[Int](q:List[Int]=(1 to 100).toList):List[String] = {
  fb.foldLeft(List[String]())( (u, v) =>

alexland

require(zoo)
require(xts)

#---------------------- mock an irregular (non-uniform interval) time series -----------------------#
start <- Sys.time() - (20 * 60 * 60)
end <- Sys.time()

# create the time series index
idx_ts = seq.POSIXt(start, end, by='hours')

alexland

def xtab(*cols, apply_wt=False):
  '''
  returns:
    (i) xt, NumPy array storing the xtab results, number of dimensions is equal to 
        the len(args) passed in
    (ii) unique_vals_all_cols, a tuple of 1D NumPy array for each dimension 
        in xt (for a 2D xtab, the tuple comprises the row and column headers)
    pass in:
      (i) 1 or more 1D NumPy arrays of integers
      (ii) if wts is True, then the last array in cols is an array of weights

alexland

/**
 * Solves the n-Queen puzzle in O(n!)
 * Let p[r] be the column of the queen on the rth row (must be exactly 1 queen per row)
 * There also must be exactly 1 queen per column and hence p must be a permuation of (0 until i)
 * There must be n distinct (col + diag) and n distinct (col - diag) for each queen (else bishop attacks)
 * @return a Vector p of length n such that p[i] is the column of the queen on the ith row
 */
def nQueens(n: Int) = (0 until n).permutations filter {p =>   
  p.zipWithIndex.flatMap{case (c, d) => Seq(n + c + d, c - d)}.distinct.size == 2*n  
}

alexland

# at the R REPL prompt

devtools::install_github('IRkernel/repr')

devtools::install_github("IRkernel/IRdisplay")

devtools::install_github("IRkernel/IRKernel")

require(IRdisplay)