Mathematica Tutorial

Adding, Removing and Modifying List Elements

Prepend[list,element]	add element at the beginning of list
Append[list,element]	add element at the end of list
Insert[list,element,i]	insert element at position i in list
Insert[list,element,-i]	insert at position i counting from the end of list
Riffle[list,element]	interleave element between the entries of list
Delete[list,i]	delete the element at position i in list
ReplacePart[list,i->new]	replace the element at position i in list with new
ReplacePart[list,{i,j}->new]	replace list[[i, j]] with new

Functions for manipulating elements in explicit lists.

This gives a list with x prepended.

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This inserts x so that it becomes element number 2.

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This interleaves x between the entries of the list.

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This replaces the third element in the list with x.

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This replaces the 1, 2 element in a 2×2 matrix.

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Functions like ReplacePart take explicit lists and give you new lists. Sometimes, however, you may want to modify a list "in place", without explicitly generating a new list.