Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
877 views
in Technique[技术] by (71.8m points)

ios - Swift use sizeof with Int32 Array

i want to get the Length of an Array with "sizeof". I tried everything. This is the error message: "[Int32] is not convertible to T.Type"

The Array has to be Int32.

var testArray: [Int32] = [2000,400,5000,400]
var arrayLength = sizeof(testArray)
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

You can get the number of elements in an array simply with

let count = testArray.count

and the total number of bytes of its elements with

var arrayLength = testArray.count * sizeof(Int32)
// Swift 3:
var arrayLength = testArray.count * MemoryLayout<Int32>.size

sizeof is used with types and sizeofValue with values, so both

var arrayLength = sizeof([Int32])
var arrayLength = sizeofValue(testArray)

would compile. But that gives you the size of the struct Array, not the size of the element storage.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...