假设您希望从格式化的电话号码中找到部分文本，并希望标记该发现。
例如，如果您具有以下电话号码：“ + 972 50-123-4567”，并且搜索2501，则可以在其中标记“ 2 50-1”中的文本。
如果要搜索的文本为“ +972 50-123-45678”，并且允许的字符为“ 01234567890 + *＃”，则显示查询哈希表和预期结果的更多示例：
val tests = hashMapOf(
"" to Pair(0, 0),
"9" to Pair(1, 2),
"97" to Pair(1, 3),
"250" to Pair(3, 7),
"250123" to Pair(3, 11),
"250118" to null,
"++" to null,
"8" to Pair(16, 17),
"+" to Pair(0, 1),
"+8" to null,
"78" to Pair(15, 17),
"5678" to Pair(13, 17),
"788" to null,
"+ " to Pair(0, 1),
" " to Pair(0, 0),
"+ 5" to null,
"+ 9" to Pair(0, 2)
)
您可能会想：为什么不只使用“ indexOf”或清理字符串并查找出现的内容呢？
但这是错误的，因为我想标记事件的发生，而忽略了途中的某些字符。
工作了一段时间后，我实际上有了答案。只是想分享它，并有选择地看看是否有人可以编写更好或更短的代码，这将产生相同的行为。
我以前有一个解决方案，该解决方案要短得多，但是它假定查询仅包含允许的字符。
这次没有问题了，因为我自己找到了答案。
不过，再次，如果您能想到一种更优雅和/或更短的解决方案，该解决方案与我所写的一样有效，请告诉我。
我敢肯定，正则表达式可以在这里解决，但有时它们有时不可读，并且与精确代码相比效率很低。仍然很高兴知道这种问题如何解决。也许我也可以对此执行一个小的基准测试。
答案 0 :(得分：0)
好的，这是我的解决方案，其中包括用于测试的示例：
TextSearchUtil.kt
object TextSearchUtil {
/**@return where the query was found. First integer is the start. The second is the last, excluding.
* Special cases: Pair(0,0) if query is empty or ignored, null if not found.
* @param text the text to search within. Only allowed characters are searched for. Rest are ignored
* @param query what to search for. Only allowed characters are searched for. Rest are ignored
* @param allowedCharactersSet the only characters we should be allowed to check. Rest are ignored*/
fun findOccurrenceWhileIgnoringCharacters(text: String, query: String, allowedCharactersSet: HashSet<Char>): Pair<Int, Int>? {
//get index of first char to search for
var searchIndexStart = -1
for ((index, c) in query.withIndex())
if (allowedCharactersSet.contains(c)) {
searchIndexStart = index
break
}
if (searchIndexStart == -1) {
//query contains only ignored characters, so it's like an empty one
return Pair(0, 0)
}
//got index of first character to search for
if (text.isEmpty())
//need to search for a character, but the text is empty, so not found
return null
var mainIndex = 0
while (mainIndex < text.length) {
var searchIndex = searchIndexStart
var isFirstCharToSearchFor = true
var secondaryIndex = mainIndex
var charToSearch = query[searchIndex]
secondaryLoop@ while (secondaryIndex < text.length) {
//skip ignored characters on query
if (!isFirstCharToSearchFor)
while (!allowedCharactersSet.contains(charToSearch)) {
++searchIndex
if (searchIndex >= query.length) {
//reached end of search while all characters were fine, so found the match
return Pair(mainIndex, secondaryIndex)
}
charToSearch = query[searchIndex]
}
//skip ignored characters on text
var c: Char? = null
while (secondaryIndex < text.length) {
c = text[secondaryIndex]
if (allowedCharactersSet.contains(c))
break
else {
if (isFirstCharToSearchFor)
break@secondaryLoop
++secondaryIndex
}
}
//reached end of text
if (secondaryIndex == text.length) {
if (isFirstCharToSearchFor)
//couldn't find the first character anywhere, so failed to find the query
return null
break@secondaryLoop
}
//time to compare
if (c != charToSearch)
break@secondaryLoop
++searchIndex
isFirstCharToSearchFor = false
if (searchIndex >= query.length) {
//reached end of search while all characters were fine, so found the match
return Pair(mainIndex, secondaryIndex + 1)
}
charToSearch = query[searchIndex]
++secondaryIndex
}
++mainIndex
}
return null
}
}
使用示例进行测试：
MainActivity.kt
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
//
val text = "+972 50-123-45678"
val allowedCharacters = "01234567890+*#"
val allowedPhoneCharactersSet = HashSet<Char>(allowedCharacters.length)
for (c in allowedCharacters)
allowedPhoneCharactersSet.add(c)
//
val tests = hashMapOf(
"" to Pair(0, 0),
"9" to Pair(1, 2),
"97" to Pair(1, 3),
"250" to Pair(3, 7),
"250123" to Pair(3, 11),
"250118" to null,
"++" to null,
"8" to Pair(16, 17),
"+" to Pair(0, 1),
"+8" to null,
"78" to Pair(15, 17),
"5678" to Pair(13, 17),
"788" to null,
"+ " to Pair(0, 1),
" " to Pair(0, 0),
"+ 5" to null,
"+ 9" to Pair(0, 2)
)
for (test in tests) {
val result = TextSearchUtil.findOccurrenceWhileIgnoringCharacters(text, test.key, allowedPhoneCharactersSet)
val isResultCorrect = result == test.value
val foundStr = if (result == null) null else text.substring(result.first, result.second)
when {
!isResultCorrect -> Log.e("AppLog", "checking query of \"${test.key}\" inside \"$text\" . Succeeded?$isResultCorrect Result: $result found String: \"$foundStr\"")
foundStr == null -> Log.d("AppLog", "checking query of \"${test.key}\" inside \"$text\" . Succeeded?$isResultCorrect Result: $result")
else -> Log.d("AppLog", "checking query of \"${test.key}\" inside \"$text\" . Succeeded?$isResultCorrect Result: $result found String: \"$foundStr\"")
}
}
//
Log.d("AppLog", "special cases:")
Log.d("AppLog", "${TextSearchUtil.findOccurrenceWhileIgnoringCharacters("a", "c", allowedPhoneCharactersSet) == Pair(0, 0)}")
Log.d("AppLog", "${TextSearchUtil.findOccurrenceWhileIgnoringCharacters("ab", "c", allowedPhoneCharactersSet) == Pair(0, 0)}")
Log.d("AppLog", "${TextSearchUtil.findOccurrenceWhileIgnoringCharacters("ab", "cd", allowedPhoneCharactersSet) == Pair(0, 0)}")
Log.d("AppLog", "${TextSearchUtil.findOccurrenceWhileIgnoringCharacters("a", "cd", allowedPhoneCharactersSet) == Pair(0, 0)}")
}
}
如果我想突出显示结果，可以使用类似的内容：
val pair = TextSearchUtil.findOccurrenceWhileIgnoringCharacters(text, "2501", allowedPhoneCharactersSet)
if (pair == null)
textView.text = text
else {
val wordToSpan = SpannableString(text)
wordToSpan.setSpan(BackgroundColorSpan(0xFFFFFF00.toInt()), pair.first, pair.second, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
textView.setText(wordToSpan, TextView.BufferType.SPANNABLE)
}