如何获取index(of :)以返回多个索引?
这是一个组数组。
var group = ["H","H","E","D", "G","D","G","E",
"D","B","A","B",
"A","A","G","C",
"C","H","D","G",
"H","B","E","F",
"F","C","E","A",
"B","C","F","F"]
我想做这样的事情来找到“ A”的索引。
group.index(of: "A"!)
但这将仅返回第一个索引,而后三个“ A”则不返回其他索引。
print(group.index(of: "A")!) //10
如何使程序返回“ A”的所有四个索引?
回答:
您可以使用的组合enumerated
和compactMap
:
let indexArray = group.enumerated().compactMap { $0.element == "A" ? $0.offset : nil
}
print(indexArray) // [10, 12, 13, 27]
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