VisibleList _ List -- get some entries of a list

Synopsis

• Operator: _

• Usage:

  w_{i,j,...}

• Inputs:
  • w, a visible list
  • {i,j,...}, a list of integers to serve as indices
• Outputs:
  • a visible list, the list of entries {w_i, w_j, ...}

Description

The entries of w are numbered starting with 0. If i is negative, then the i-th entry counting from the end is provided. If i is out of range, an error is signaled.

i1 : w = {a,b,c,d,e,f,g,h}

o1 = {a, b, c, d, e, f, g, h}

o1 : List

i2 : w_{1,3,4}

o2 = {b, d, e}

o2 : List

i3 : w_{-1,-2,-3}

o3 = {h, g, f}

o3 : List

i4 : {4,2,3,1,0} _ {2,1,3,4,0}

o4 = {3, 2, 1, 0, 4}

o4 : List

i5 : {a,b,c,d,e}_{2..4}

o5 = {c, d, e}

o5 : List

See also

• lists and sequences -- a detailed overview of lists and sequences in Macaulay2
• VisibleList _ ZZ -- get element from list