arrays - scala 数组[字节] diff

Question

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

diff() 对于 (subString diff originString) 返回 true，但对于 返回 false (原始字符串差异子字符串)。如果有人能解释这一点，那就太好了。下面给出了代码示例和输出。

代码片段

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；这就像设置差异，“第一个字符串中但第二个字符串中没有的字符是什么？”

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

所以这些几乎是等价的:

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