Array Add vs

Question

I ve found some interesting behaviour in PowerShell Arrays  namely  if I declare an array as    array         And then try to add items to it using the  array Add  item   method  I receive the following error      Exception calling  Add  with  1  argument s    Collection was of a fixed size     However  if I append items using  array     item   the item is accepted without a problem and the  fixed size  restriction doesn t seem to apply   Why is this

User · Answer

If you want a dynamically sized array  then you should make a list  Not only will you get the  Add   functionality  but as  frode-f explains  dynamic arrays are more memory efficient and a better practice anyway   And it s so easy to use   Instead of your array declaration  try this    outItems   New-Object System Collections Generic List System Object    Adding items is simple    outItems Add 1   outItems Add  hi     And if you really want an array when you re done  there s a function for that too    outItems ToArray

User · Answer

When using the  array Add  -method  you re trying to add the element into the existing array  An array is a collection of fixed size  so you will receive an error because it can t be extended    array     element creates a new array with the same elements as old one   the new item  and this new larger array replaces the old one in the  array-variable      You can use the    operator to add an element to an array  When you   use       it  Windows PowerShell actually creates a new array with the values of the       original array and the added value  For example  to add an element with a        value of 200 to the array in the  a variable  type        a    200    Source  about Arrays     is an expensive operation  so when you need to add many items you should try to add them in as few operations as possible  ex    arr   1  3     Array  arr     4  5   Combine with another array in a single write-operation   arr Count 5   If that s not possible  consider using a more efficient collection like List or ArrayList  see the other answer

User · Answer

The most common idiom for creating an array without using the inefficient    is something like this  from the output of a loop    array   foreach  i in 1  10        i    array

[arrays] Array.Add vs +=

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