scala数组[字节]差异

Question

我使用diff方法来比较两个String的字节数组，但是给出了意外的（或者是预期的行为？）结果。

diff()会为true返回(subString diff originalString)，但会为false返回(originalString diff subString)。如果任何人都可以解释这一点，那就太好了。代码示例＆amp;输出如下。

代码段

val subString : Array[Byte] = "cde".getBytes("UTF-8")
val originalString : Array[Byte] = "abcdefg".getBytes("UTF-8")

println(s"compare subString with originalString - ${((subString diff originalString).isEmpty).toString}")
println(s"compare originalString with subString - ${((originalString diff subString).isEmpty).toString}")

输出

compare subString with originalString - true

compare originalString with subString - false

Answer 1

diff不是比较;它就像设置差异一样，＆＃34;第一个字符串中的字符是什么，而第二个字符串中没有？＆＃34;

"abcd" diff "a" = "bcd"
"a" diff "abcd" = ""

所以这些几乎等同于：

"abc".toSet diff "cb".toSet = Set(a)
"abc" diff "cb" = "a"