Swift_字符串详解(String)
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类型别名
//类型别名
fileprivate func testTypeAliases() {
let index = String.Index.self
print("\(index)")
let utf8index = String.UTF8Index.self
print("\(utf8index)")
let utf16index = String.UTF16Index.self
print("\(utf16index)")
let unicodeScalarIndex = String.UnicodeScalarIndex.self
print("\(unicodeScalarIndex)")
let greeting = "XuBaoAiChiYu"
print(greeting[greeting.startIndex])//输出字符串的第一个字符
print(greeting[greeting.characters.index(before: greeting.endIndex)])//输出字符串的最后一个字符
print(greeting[greeting.characters.index(after: greeting.startIndex)])//输出字符串的第二个字符
print(greeting[greeting.characters.index(greeting.startIndex, offsetBy: 7)])//输出字符串的第八个字符
/* print
Index
Index
Index
Index
X
u
u
C
*/
}
初始化
//初始化
fileprivate func testInitializers() {
//初始化
var string: String = String()
string = "XuBaoAiChiYu"
print(string)
//char 初始化
let char: Character = "X"
string = String(char)
print(string)
string = String.init(char)
print(string)
string = "\(char)"
print(string)
// 通过CharacterView
let charView: String.CharacterView = String.CharacterView("XuBaoAiChiYu")
string = String(charView)
print(string)
//通过 utf-16 编码
let utf16: String.UTF16View = string.utf16
string = String(describing: utf16)
print(utf16)
//通过 utf-8 编码
let utf8: String.UTF8View = string.utf8
string = String(describing: utf8)
print(utf8)
//通过多个字符串组合生成
string = String(stringInterpolation: "xu", "bao")
print(string)
//char初始化 连续count次
string = String(repeating: String(char), count: 6)
print(string)
//通过其他常用数据初始化
string = String(stringInterpolationSegment: true)
print(string)
string = String(stringInterpolationSegment: 24)
print(string)
// 通过NSString初始化,不推荐
string = NSString(string: "XuBaoAiChiYu") as String
print(string)
string = NSString.init(string: "XuBaoAiChiYu") as String
print(string)
// 组合生成
string = NSString(format: "%@", "XuBaoAiChiYu") as String
print(string)
/* print
XuBaoAiChiYu
X
X
X
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
xubao
XXXXXX
true
24
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
*/
}
文件路径操作
//文件路径操作
fileprivate func testWorkingWithPaths() {
var path = "xubaoaichiyu/ios/swift"
print(path)
//路径分割成熟数组
var pathComponents = (path as NSString).pathComponents
print(pathComponents)
//数组组合成路径
path = NSString.path(withComponents: pathComponents)
print(path)
//Document目录
let documents: [String] = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, .userDomainMask, true)
print(documents)
let documentPath: String = documents.first!
print(documentPath)
//寻找文件夹下包含多少个路径
var complete = documentPath.completePath(caseSensitive: true)
print(complete)
//寻找文件夹下包含指定扩展名的文件路径个数
var outName = ""
let filterTypes = ["txt", "plist"]
complete = documentPath.completePath(into: &outName, caseSensitive: true, matchesInto: &pathComponents, filterTypes: filterTypes)
print("completePathIntoString:\(complete)")
//添加路径
path = (documentPath as NSString).appendingPathComponent("test")
print(path)
//添加扩展
path = (path as NSString).appendingPathExtension("plist")!
print(path)
print("是否绝对路径:\((path as NSString).isAbsolutePath)")
print("最后一个路径名:\((path as NSString).lastPathComponent)")
print("扩展名:\((path as NSString).pathExtension)")
//去掉扩展名
var tempPath = (path as NSString).deletingPathExtension
print(tempPath)
//去掉最后一个路径
tempPath = (path as NSString).deletingLastPathComponent
print(tempPath)
//转%格式码
let allowedCharacters:CharacterSet = CharacterSet.controlCharacters
tempPath = path.addingPercentEncoding(withAllowedCharacters: allowedCharacters)!
print(tempPath)
//转可见
tempPath = (tempPath as NSString).removingPercentEncoding!
print(tempPath)
/* print
xubaoaichiyu/ios/swift
["xubaoaichiyu", "ios", "swift"]
xubaoaichiyu/ios/swift
["/Users/caoxu/Documents"]
/Users/caoxu/Documents
4
completePathIntoString:1
/Users/caoxu/Documents/test
/Users/caoxu/Documents/test.plist
是否绝对路径:true
最后一个路径名:test.plist
扩展名:plist
/Users/caoxu/Documents/test
/Users/caoxu/Documents
%2F%55%73%65%72%73%2F%63%61%6F%78%75%2F%44%6F%63%75%6D%65%6E%74%73%2F%74%65%73%74%2E%70%6C%69%73%74
/Users/caoxu/Documents/test.plist
*/
}
文件读写操作
//文件读写操作
fileprivate func testFile() {
var string = "XuBaoAiChiYu"
//Document目录
let documents = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)
var path = documents.first!
path = (path as NSString).appendingPathComponent("xubaoaichiyu")
path = (path as NSString).appendingPathExtension("text")!
let pathUrl = URL(fileURLWithPath: path)
do {
//写入
try string.write(toFile: path, atomically: true, encoding: String.Encoding.utf8)
try string.write(to: pathUrl, atomically: true, encoding: String.Encoding.utf8)
// 读取
// 自动解析
try string = String(contentsOfFile: path)
print(string)
// 指定编码解析
try string = String(contentsOfFile: path, encoding: String.Encoding.utf8)
print(string)
// 使用默认的编码解析 如果不能解析 采取默认解析并返回解析编码
var encoding:String.Encoding = String.Encoding.utf16LittleEndian
try string = String(contentsOfFile: path, usedEncoding: &encoding)
print(string)
// URl 读取
try string = String(contentsOf: pathUrl)
print(string)
try string = String(contentsOf: pathUrl, encoding: String.Encoding.utf8)
print(string)
try string = String(contentsOf: pathUrl, usedEncoding: &encoding)
print(string)
} catch {
print("错误:\(error)")
}
/* print
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
XuBaoAiChiYu
*/
}
获取字符串的Swift属性
//获取字符串的Swift属性
fileprivate func testGettingProperties() {
let string = String(stringInterpolation: "XuBaoAiChiYu", "QQ", "1045214799")
// String.CharacterView
print("String.CharacterView:\(string.characters)")
// String.UnicodeScalarView
print("String.UnicodeScalarView:\(string.unicodeScalars)")
// String.UTF16View
print("String.UTF16View:\(string.utf16)")
// String.UTF8View
print("String.UTF8View:\(string.utf8)")
// hash值
print("hashValue:\(string.hashValue)")
// 是否为空
print("isEmpty:\(string.isEmpty)")
/* print
String.CharacterView:CharacterView(_core: Swift._StringCore(_baseAddress: Optional(0x0000000100b06e80), _countAndFlags: 24, _owner: Optional(Swift._HeapBufferStorage<Swift._StringBufferIVars, Swift.UInt16>)))
String.UnicodeScalarView:XuBaoAiChiYuQQ1045214799
String.UTF16View:XuBaoAiChiYuQQ1045214799
String.UTF8View:XuBaoAiChiYuQQ1045214799
hashValue:-8659559252040524018
isEmpty:false
*/
}
获取字符串长度
//获取字符串长度
fileprivate func testGettingLength() {
var string: String = String()
string = "XuBaoAiChiYu: 1045214799"
// 起始位置
var index = string.startIndex
print(index)
// 结束位置
index = string.endIndex
print(index)
// NSString方式获取长度
var length = (string as NSString).length
print(length)
// swift方式获取
length = string.characters.distance(from: string.startIndex, to: string.endIndex)
print(length)
// 通过编码获取长度
length = string.lengthOfBytes(using: String.Encoding.utf8)
print(length)
/* print
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1)
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 24), _countUTF16: 0)
24
24
24
*/
}
大小写变化
//大小写变化
fileprivate func testChangingCase() {
var string = "XuBaoAiChiYu QQ 1045214799"
print(string)
//大写
string = string.uppercased()
print(string)
//小写
string = string.lowercased()
print(string)
/* print
XuBaoAiChiYu QQ 1045214799
XUBAOAICHIYU QQ 1045214799
xubaoaichiyu qq 1045214799
*/
}
字符串转数值
//字符串转数值
fileprivate func testGettingNumericValues() {
let string = "24"
print(string)
let nStr = string as NSString // 借用NSString输出
print(nStr)
print("doubleValue:\(nStr.doubleValue)")
print("floatValue:\(nStr.floatValue)")
print("intValue:\(nStr.intValue)")
print("integerValue:\(nStr.integerValue)")
print("longLongValue:\(nStr.longLongValue)")
print("boolValue:\(nStr.boolValue)")
/* print
24
24
doubleValue:24.0
floatValue:24.0
intValue:24
integerValue:24
longLongValue:24
boolValue:true
*/
}
增加字符串
//增加字符串
fileprivate func testCombiningStrings() {
var string = "XuBaoAiChiYu QQ 1045214799"
print(string)
// 添加字符串
string.append("_Swift")
print(string)
string += "_Swift"
print(string)
string.write("_Swift")
print(string)
// string后增加字符串并生成一个新的字符串
string = string + string
print(string)
// string后增加组合字符串并生成一个新的字符串
string = string.appendingFormat("_%@", "OC")
print(string)
// string后增加循环字符串，stringByPaddingToLength：完毕后截取的长度；startingAtIndex：从增加的字符串第几位开始循环增加。
string = string.padding(toLength: 30, withPad:"_Swift", startingAt:3)
print(string)
// 指定位置插入Character
string.insert("5", at: string.characters.index(string.endIndex, offsetBy: -1))
print(string)
// 指定位置插入字符串
string.insert(contentsOf: "78".characters, at: string.characters.index(string.startIndex, offsetBy: 9))
print(string)
/* print
XuBaoAiChiYu QQ 1045214799
XuBaoAiChiYu QQ 1045214799_Swift
XuBaoAiChiYu QQ 1045214799_Swift_Swift
XuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift
XuBaoAiChiYu QQ 1045214799_Swift_Swift_SwiftXuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift
XuBaoAiChiYu QQ 1045214799_Swift_Swift_SwiftXuBaoAiChiYu QQ 1045214799_Swift_Swift_Swift_OC
XuBaoAiChiYu QQ 1045214799_Swi
XuBaoAiChiYu QQ 1045214799_Sw5i
XuBaoAiCh78iYu QQ 1045214799_Sw5i
*/
}
分割字符串
//分割字符串
fileprivate func testDividingStrings() {
let str = "XuBaoAiChiYu_QQ_1045214799"
//根据指定的字符串分割成数组
var array = str.components(separatedBy: "_")
print(array)
//通过系统自带的分割方式分割字符串
array = str.components(separatedBy: CharacterSet.lowercaseLetters)
print(array)
// 指定位置后的字符串
var tempStr = str.substring(from: str.characters.index(str.startIndex, offsetBy: 3))
print(tempStr)
// 指定位置前的字符串
tempStr = str.substring(to: str.characters.index(str.startIndex, offsetBy: 3))
print(tempStr)
// 指定范围的字符串
let range = str.characters.index(str.endIndex, offsetBy: -6)..<str.endIndex
tempStr = str.substring(with: range)
print(tempStr)
/* print
["XuBaoAiChiYu", "QQ", "1045214799"]
["X", "B", "", "A", "C", "", "Y", "_QQ_1045214799"]
aoAiChiYu_QQ_1045214799
XuB
214799
*/
}
查找字符串
//查找字符串
fileprivate func testFindingStrings() {
let str = "XuBaoAiChiYu_QQ_1045214799";
let searchRange = str.startIndex ..< str.characters.index(str.startIndex, offsetBy: 10)
print(searchRange)
//根据NSCharacterSet查找
let cSet = CharacterSet.uppercaseLetters
var range = str.rangeOfCharacter(from: cSet)
print(range!)
//根据字符串查找
range = str.range(of: "Yu")
print(range!)
range = str.range(of: "Yu", options: NSString.CompareOptions.caseInsensitive, range: searchRange, locale: nil)
if let tempRange = range {
print("tempRange:\(tempRange)")
}
//block 行查找
str.enumerateLines { (line, stop) -> () in
print(line)
if "Yu" == line {
stop = true
}
}
//block查找 可设置查找方式 并得到找到的位置
str.enumerateSubstrings(in: searchRange, options: NSString.EnumerationOptions.byComposedCharacterSequences) { (substring, substringRange, enclosingRange, stop) -> () in
print(substring!)
if "A" == substring {
print(substringRange)
stop = true
}
}
/* print
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 10), _countUTF16: 1)
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 0), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 1), _countUTF16: 1)
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 10), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 12), _countUTF16: 1)
XuBaoAiChiYu_QQ_1045214799
X
u
B
a
o
A
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 5), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 6), _countUTF16: 1)
*/
}
替换字符串
//替换字符串
fileprivate func testReplacingSubstrings() {
var string = "XuBaoAiChiYu_QQ_1045214799"
let replacingRange = string.startIndex..<string.characters.index(string.startIndex, offsetBy: 20)
print(string)
//全局替换
string = string.replacingOccurrences(of: "+", with: " ")
print(string)
//设置替换的模式 并设置范围
string = string.replacingOccurrences(of: "+", with: "_", options: NSString.CompareOptions.caseInsensitive, range: replacingRange)
print(string)
//将指定范围的字符串替换为指定的字符串
string.replaceSubrange(replacingRange, with: "YYYYYYYYYYYYYYY")
print(string)
string = string.replacingCharacters(in: replacingRange, with: "YYYYY")
print(string)
/* print
XuBaoAiChiYu_QQ_1045214799
XuBaoAiChiYu_QQ_1045214799
XuBaoAiChiYu_QQ_1045214799
YYYYYYYYYYYYYYY214799
YYYYY9
*/
}
删除字符串
//删除字符串
fileprivate func testRemovingSubstrings() {
var string = "XuBaoAiChiYu_QQ_1045214799"
print(string)
//删除指定位置的字符串
string.remove(at: string.characters.index(string.startIndex, offsetBy: 1))
print(string)
//根据范围删除字符串
let range = string.characters.index(string.endIndex, offsetBy: -6)..<string.endIndex
string.removeSubrange(range)
print(string)
//删除所有
string.removeAll()
string.removeAll(keepingCapacity: true)
/* print
XuBaoAiChiYu_QQ_1045214799
XBaoAiChiYu_QQ_1045214799
XBaoAiChiYu_QQ_1045
*/
}
比较字符串
//比较字符串
fileprivate func testComparingStrings() {
var string = "XuBaoAiChiYu_QQ_1045214799"
let compareStr = "XuBaoAiChiYu_QQ_1045214799"
let searchRange = string.characters.index(string.startIndex, offsetBy: 5)..<string.characters.index(before: string.endIndex)
print(searchRange)
//前缀
var isHas = string.hasPrefix("Xu")
print("hasPrefix:\(isHas)")
//后缀
isHas = string.hasSuffix("1045214799")
print("hasSuffix:\(isHas)")
//全比较是否相同
isHas = string == compareStr
print(isHas)
//比较大小
var result = string.compare(compareStr)
print(result.hashValue)
//添加比较范围
result = string.compare(compareStr, options: NSString.CompareOptions.caseInsensitive, range: searchRange, locale: nil)
print("result:\(result.hashValue)")
// 返回两个字符串相同的前缀
string = string.commonPrefix(with: compareStr, options: NSString.CompareOptions.caseInsensitive)
print(string)
/* print
Index(_base: Swift.String.UnicodeScalarView.Index(_position: 5), _countUTF16: 1)..<Index(_base: Swift.String.UnicodeScalarView.Index(_position: 25), _countUTF16: 1)
hasPrefix:true
hasSuffix:true
true
1
result:0
XuBaoAiChiYu_QQ_1045214799
*/
}
