From 7b9fd4676db613a169f5e2ea105b8e02eaef9da6 Mon Sep 17 00:00:00 2001 From: Chris Ward Date: Wed, 12 Dec 2018 17:10:45 +0100 Subject: Add array item deletion idiosyncracy --- docs/types.rst | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'docs/types.rst') diff --git a/docs/types.rst b/docs/types.rst index f67a6d1a..b6003fd5 100644 --- a/docs/types.rst +++ b/docs/types.rst @@ -1189,7 +1189,14 @@ If ``a`` is an LValue (i.e. a variable or something that can be assigned to), th delete ------ -``delete a`` assigns the initial value for the type to ``a``. I.e. for integers it is equivalent to ``a = 0``, but it can also be used on arrays, where it assigns a dynamic array of length zero or a static array of the same length with all elements reset. For structs, it assigns a struct with all members reset. In other words, the value of ``a`` after ``delete a`` is the same as if ``a`` would be declared without assignment, with the following caveat: +``delete a`` assigns the initial value for the type to ``a``. I.e. for integers it is +equivalent to ``a = 0``, but it can also be used on arrays, where it assigns a dynamic +array of length zero or a static array of the same length with all elements set to their +initial value. ``delete a[x]`` deletes the item at index ``x`` of the array and leaves +all other elements and the length of the array untouched. This especially means that it leaves +a gap in the array. If you plan to remove items, a mapping is probably a better choice. + +For structs, it assigns a struct with all members reset. In other words, the value of ``a`` after ``delete a`` is the same as if ``a`` would be declared without assignment, with the following caveat: ``delete`` has no effect on mappings (as the keys of mappings may be arbitrary and are generally unknown). So if you delete a struct, it will reset all members that are not mappings and also recurse into the members unless they are mappings. However, individual keys and what they map to can be deleted: If ``a`` is a mapping, then ``delete a[x]`` will delete the value stored at ``x``. -- cgit