将Objective C中的下标函数转换为Swift

Question

我正在尝试将一些Objective C代码转换为Swift，但无法正确使用下标。这是我尝试迁移到Swift的方法：

- (NSArray *)rangesOfSubstringAlphaNumeric:(NSString *)substring rangesLimit:(NSUInteger)rangesLimit {
NSAssert(rangesLimit, @"A range limit grather than 0 must be specified");
if (!substring.length) {
return nil;
}
static NSCharacterSet * restrictedCharacters = nil;
if (!restrictedCharacters) {
restrictedCharacters = [[NSCharacterSet alphanumericCharacterSet] invertedSet];
}
NSArray * substrings = [substring componentsSeparatedByCharactersInSet:restrictedCharacters];
NSMutableArray * allRanges = [NSMutableArray array];
NSString *searchedString = self;
for (NSString *stringToMatch in substrings) {
if (![stringToMatch isEqualToString:@""]) {
NSRange aRange;
NSUInteger lastLocation = 0;
NSUInteger foundRanges = 0;
while (foundRanges++ < rangesLimit &&
(aRange = [searchedString localizedStandardRangeOfString:stringToMatch]).location != NSNotFound) {
searchedString = [searchedString substringFromIndex:aRange.location + aRange.length];
aRange.location = aRange.location + lastLocation;
lastLocation = aRange.location + aRange.length;
[allRanges addObject:[NSValue valueWithRange:aRange]];
}
}
}
return allRanges.count ? [allRanges copy] : nil;
}

我被下标部分卡住了，因为我似乎无法将整数值分配给Indexes，从Index到Int的转换对我来说已经失控了。我有点卡住了，这就是我设法做到的：

func rangesOfAlphanumeric(substring: String, limit: UInt) -> [Range<String.Index>] {
guard limit > 0, !substring.isEmpty else {
if limit == 0 {
assert(false, "limit must be greather than 0")
}
return []
}
var searchedString = self
let substrings = substring.components(separatedBy: NSCharacterSet.restricted)
for stringToMatch in substrings {
if !stringToMatch.isEmpty {
//                var aRange: Range<String.Index>?
//                var lastLocation: UInt = 0
//                var foundRanges: UInt = 0
//                while foundRanges < limit,
//                    let tempRange = searchedString.localizedStandardRange(of: stringToMatch),
//                    !tempRange.isEmpty {
//
//                        searchedString = String(searchedString[tempRange.upperBound...])
//                        if let lastLocation = lastLocation {
//                            aRange = temp
//                        }
//                }
}
}
}

更新：下面的解决方案。

Answer 1

使用此处发布的ranges函数解决了问题：

func rangesOfAlphanumeric(substring: String) -> [Range<String.Index>] {
var searchedString = self
let substrings = substring.components(separatedBy: NSCharacterSet.restricted)
return substrings.compactMap { (stringToMatch) -> [Range<String.Index>]? in
guard !stringToMatch.isEmpty else {
return nil
}
let ranges = searchedString.ranges(of: stringToMatch, options: [
.diacriticInsensitive,
.caseInsensitive
])
if let lastRange = ranges.last {
searchedString = String(searchedString[index(after: lastRange.upperBound)])
}
return ranges
}.flatMap{$0}
}

Answer 2

我用swift 5创建了这个repo，非常容易使用一切都已就绪。你只需要更改IAP ID

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