IOS swift 如何在string中的index位置再插入一个string呢，请大神们不吝赐教

Question

是不是需要转化成NSString或者NSMutableString呢，求具体的实例代码。感激不尽！

Answer 1

The index of Swift string is not easy to operate, but this requirement is not difficult to achieve

var str2 = "world"
var str1 = "hello,"
str1.insertContentsOf(str2.characters, at: str1.endIndex)
print(str1)