我需要一种方法来删除字符串的第一个字符，这是一个空格。我正在寻找一个方法，甚至是一个扩展的字符串类型，我可以用来削减字符串的字符。
当前回答
extension String {
var removingWhitespaceAndNewLines: String {
return removing(.whitespacesAndNewlines)
}
func removing(_ forbiddenCharacters: CharacterSet) -> String {
return String(unicodeScalars.filter({ !forbiddenCharacters.contains($0) }))
}
}
其他回答
嗨，这可能有点晚，但值得一试。这是一个游乐场的文件。你可以让它成为一个字符串扩展名。
这是在Swift 5.3中编写的
方法1:
var str = "\n \tHello, playground "
if let regexp = try? NSRegularExpression(pattern: "^\\s+", options: NSRegularExpression.Options.caseInsensitive) {
let mstr = NSMutableString(string: str)
regexp.replaceMatches(in: mstr, options: [], range: NSRange(location: 0, length: str.count), withTemplate: "")
str = mstr as String
}
Result: "Hello, playground "
方法2:
if let c = (str.first { !($0 == " " || $0 == "\t" || $0 == "\n") }) {
if let nonWhiteSpaceIndex = str.firstIndex(of: c) {
str.replaceSubrange(str.startIndex ..< nonWhiteSpaceIndex, with: "")
}
}
Result: "Hello, playground "
如果有人从字符串中删除额外的空格，例如= "这是演示文本，请在单词之间删除额外的空格。"
你可以在Swift 4中使用这个函数。
func removeSpace(_ string: String) -> String{
var str: String = String(string[string.startIndex])
for (index,value) in string.enumerated(){
if index > 0{
let indexBefore = string.index(before: String.Index.init(encodedOffset: index))
if value == " " && string[indexBefore] == " "{
}else{
str.append(value)
}
}
}
return str
}
结果是
"This is the demo text remove extra space between the words."
extension String {
var removingWhitespaceAndNewLines: String {
return removing(.whitespacesAndNewlines)
}
func removing(_ forbiddenCharacters: CharacterSet) -> String {
return String(unicodeScalars.filter({ !forbiddenCharacters.contains($0) }))
}
}
尝试函数式编程来删除空白:
extension String {
func whiteSpacesRemoved() -> String {
return self.filter { $0 != Character(" ") }
}
}
这个String扩展删除了字符串中的所有空格，而不仅仅是尾随空格…
extension String {
func replace(string:String, replacement:String) -> String {
return self.replacingOccurrences(of: string, with: replacement, options: NSString.CompareOptions.literal, range: nil)
}
func removeWhitespace() -> String {
return self.replace(string: " ", replacement: "")
}
}
例子:
let string = "The quick brown dog jumps over the foxy lady."
let result = string.removeWhitespace() // Thequickbrowndogjumpsoverthefoxylady.
