Read and set an element in a Java array.
lw-ji
jaref array &rest indices => element
setf (jaref array &rest indices) new-value => new-value
array⇩ |
A Java array, of any type. |
indices⇩ |
Non-negative integers. |
new-value⇩ |
A valid element for array. |
element |
A Lisp object, a jobject or nil . |
new-value |
A valid element for array. |
The accessor jaref
reads and sets the value of an element in the Java array array.
Each element of indices must be an integer in the right range, which means greater than or equal to 0, and less than than the length of the sub-array ("current array" below) for which they are used. There must be at least one index, and the number of indices must be smaller or equal to the array rank (that is, the number of dimensions) of array.
new-value must be a valid value to store in array. It has the same restrictions as new-value in (setf jvref)
. See the discussion in jvref for details.
The operation of jaref
and (setf jaref)
is as follows: For each index except the last, load the element from the "current array", which is the array itself for the first index or the element that was loaded for the previous index. When reaching the last index, jaref
and (setf jaref)
get or set the element in the "current array" the same way that jvref does. Note that this means that if there are less indices than number of the dimensions of the array, the access will be for a sub-array rather than actual element.
Because jaref
needs to load the sub-array for each index except the last, repeated calls to jaref
for elements inside the same array are wasteful. It is much more efficient to get the sub-array and access it using jvref, or the multiple access functions.
jvref
map-java-object-array
primitive-array-to-lisp-array
lisp-array-to-primitive-array
15.4 Working with Java arrays
LispWorks® User Guide and Reference Manual - 01 Dec 2021 19:30:46