Scala中的Array[Byte] diff

Question

我正在使用diff方法来比较两个字符串的字节数组，但结果与预期不符（或者说是预期的行为？）。

对于(subString diff originalString)，diff()返回true，但对于(originalString diff subString)，则返回false。如果有人能解释一下就太好了。以下是代码示例和输出。

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

- Sunil

Answer 1

diff 不是 比较；它更像是集合差异，"第一个字符串中有哪些字符不在第二个字符串中？"

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

因此，这些几乎是等价的：

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

- perreal