PadLeft

PadLeft[list,n]
makes a list of length n by padding list with zeros on the left.

PadLeft[list,n,x]
pads by repeating the element x.

PadLeft[list,n,{x1,x2,}]
pads by cyclically repeating the elements .

PadLeft[list,n,padding,m]
leaves a margin of m elements of padding on the right.

PadLeft[list,{n1,n2,}]
makes a nested list with length at level i.

PadLeft[list]
pads a ragged array list with zeros to make it full.

DetailsDetails

  • PadLeft[list,n,] always returns a list of length n, except in some special cases where padding is .
  • With padding , cyclic repetitions of the are effectively laid down and then the list is superimposed on top of them, with the last element of the list lying on an occurrence of . »
  • PadLeft[list,n,padding,-m] truncates the last m elements of list.
  • A margin of Round[(n-Length[list])/2] effectively centers list.
  • PadLeft[list,n,list] effectively treats list as cyclic.
  • PadLeft[list,n,{xlist}] can be used to repeat an individual element that is itself a list.
  • PadLeft[{},n,{x1,x2,}] repeats the sequence of as many times as fit in a list of length n.
  • PadLeft[list,{n1,n2,}] creates a full array with dimensions even if list is ragged. »
  • PadLeft[list,Automatic,x] pads with x to make a full array.
  • Negative specify to pad on the right.
  • PadLeft[list,{n1,n2},{{x11,x12,},{x21,},}] pads by repeating the block of .
  • PadLeft[list,{n1,n2,},list] effectively treats list as cyclic in every dimension.
  • PadLeft[list,{n1,n2,},padding,{m1,m2,}] uses margin at level i.
  • The object list need not have head List.
  • PadLeft can be used on SparseArray objects.

ExamplesExamplesopen allclose all

Basic Examples  (6)Basic Examples  (6)

Pad with to make the list be of length 10:

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Pad with :

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Pad by repeating :

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Leave margin on the right:

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Pad to make a 3×5 array:

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Pad to make a full array:

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Introduced in 1999
(4.0)
| Updated in 2007
(6.0)