基础知识拾遗代码片段iOS精華

NSCharacterSet 字符集的使用

2017-08-15  本文已影响141人  yuJiaMoMo
1.简介

NSCharacterSet ，以及它的可变类型 NSMutableCharacterSet，用面向对象的方式来表示一组Unicode字符。它经常与NSString及NSScanner组合起来使用，在不同的字符上做过滤、删除或者分割操作。

1.1 先来看下面的例子

需求： 有一个字符串:@"今天我们来学习NSCharacterSet我们快乐"，去除字符串中所有的@"今"、@"我"、@"s"。 【注意】s是小写 思考：如果是你怎么解决？ 自己写。 用 NSCharacterSet

1.1.1 自己写,如下：
NSString *str = @"今天我们来学习NSCharacterSet我们快乐";
    NSString *str1 = @"我s今";
    NSMutableString *resultStr = [[NSMutableString alloc]init];
    for (int i = 0; i < str.length; i++) {
        NSString *indexStr = [str substringWithRange:NSMakeRange(i, 1)];
        if (![str1 containsString:indexStr]) {
            [resultStr appendString:indexStr];
        }
    }

    NSLog(@"自己写---%@",resultStr);

   //输出结果 "自己写---天们来学习NSCharacterSet们快乐"
1.1.2 用 NSCharacterSet,如下：
NSString *str = @"今天我们来学习NSCharacterSet我们快乐";
    NSCharacterSet *characterSet = [NSCharacterSet characterSetWithCharactersInString:@"我s今"];
    NSArray *setArr = [str componentsSeparatedByCharactersInSet:characterSet];
    NSString *resultStr1 = [setArr componentsJoinedByString:@""];
    NSLog(@"拆分后的字符串数组------%@\n最终字符串------%@",setArr,resultStr1);
 //输出结果 "自己写---天们来学习NSCharacterSet们快乐"

总结： 至此，通过上面的两个方法，已经解决了需求的问题。通过自己写，结合用NSCharacterSet，可以推断出NSCharacterSet类似一个字符串处理工具类，而事实上，由名字也可以看出，它确实是！

2.方法和属性介绍：
NSCharacterSet 中提供的下面属性都是只读的, 且在NSMutableCharacterSet中有一致的类方法

1.controlCharacterSet //控制符的字符集

2.whitespaceCharacterSet //空格的字符集

3.whitespaceAndNewlineCharacterSet //空格和换行符的字符集

4.decimalDigitCharacterSet //十进制数字的字符集

5.letterCharacterSet //字母的字符集

6.lowercaseLetterCharacterSet //小写字母的字符集

7.uppercaseLetterCharacterSet //大写字母的字符集

8.nonBaseCharacterSet //非基础的字符集

9.alphanumericCharacterSet //字母和数字的字符集

10.decomposableCharacterSet //可分解

11.illegalCharacterSet //非法的字符集

12.punctuationCharacterSet //标点的字符集

13.capitalizedLetterCharacterSet //首字母大写的字符集

14.symbolCharacterSet //符号的字符集

15.newlineCharacterSet //换行符的字符集

NSCharacterSet 和 NSMutableCharacterSet一致的类方法

//返回一个指定范围的字符集,取自小写字母字符集

+ (NSCharacterSet *)characterSetWithRange:(NSRange)aRange;

//返回一个包含当前字符串的字符集

+ (NSCharacterSet *)characterSetWithCharactersInString:(NSString *)aString;

//返回包含由给定位图表示形式确定的字符的字符集,此方法对于使用来自文件或其他外部数据源的数据创建字符集

+ (NSCharacterSet *)characterSetWithBitmapRepresentation:(NSData *)data;

//返回从位图表示中读取的字符集,存储在文件中给定的路径。

+ (nullable NSCharacterSet *)characterSetWithContentsOfFile:(NSString *)fName;
NSCharacterSet中的其它方法或属性：
//指定字符集是包含于在于当前字符集

- (BOOL)characterIsMember:(unichar)aCharacter;

//以二进制格式编码接收器的NSData对象,此格式适用于保存到文件或以其他方式传输或归档

@property (readonly, copy) NSData *bitmapRepresentation;

//反转字符集,仅包含当前字符集中不存在的字符

@property (readonly, copy) NSCharacterSet *invertedSet;
NSMutableCharacterSet中其它方法：
- (void)addCharactersInRange:(NSRange)aRange;

- (void)removeCharactersInRange:(NSRange)aRange;

- (void)addCharactersInString:(NSString *)aString;

- (void)removeCharactersInString:(NSString *)aString;

- (void)formUnionWithCharacterSet:(NSCharacterSet *)otherSet;

- (void)formIntersectionWithCharacterSet:(NSCharacterSet *)otherSet;

- (void)invert;
举例使用
1.去掉首尾空格
NSString *testString = @"      This is the string contains whitespace in beginning and ending    ";

NSString *whitesspaceStr = [testString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

NSLog(@"%@",whitesspaceStr);



打印结果: This is the string contains whitespace in beginning and ending
2.去除首尾指定字符串
NSString *str=@"哈哈呵呵嘿嘿吼吼";

NSCharacterSet *cs= [NSCharacterSet characterSetWithCharactersInString:@"哈吼"];

NSString *strResult = [str stringByTrimmingCharactersInSet:cs];

NSLog(@"%@",strResult);



打印结果: 呵呵嘿嘿
3.用指定字符串替代当前字符中的指定字符集中的字符串
NSMutableCharacterSet *letter = [NSMutableCharacterSet lowercaseLetterCharacterSet];

NSCharacterSet *decimalDigit = [NSCharacterSet decimalDigitCharacterSet];

[letter formUnionWithCharacterSet:decimalDigit];

NSString *string = @"g8!hgr3@09#23uiq%^78sjn453t78&13gesg*wt53(545y45)q3at";

NSLog(@"%@",[[string componentsSeparatedByCharactersInSet:letter] componentsJoinedByString:@"_"]);

[letter invert];  //字母数字反转

NSLog(@"%@",[[string componentsSeparatedByCharactersInSet:letter] componentsJoinedByString:@"_"]);



打印结果:

__!____@__#_____%^___________&______*____(______)____

g8_hgr3_09_23uiq__78sjn453t78_13gesg_wt53_545y45_q3at
4.去除所有空格
NSString *string = @"  a b  cd  ef gh ij    klm  nopq rstu v  w x  y z  ";

NSLog(@"%@",[[string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] componentsJoinedByString:@""]);



打印结果: abcdefghijklmnopqrstuvwxyz
5.与NSPredicate结合使用压缩空格
NSString *string = @"  Additional    setup  after    loading the    view.";

string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

NSArray *components = [string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

components = [components filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"self <> ''"]];

string = [components componentsJoinedByString:@" "];

NSLog(@"%@", string);



打印结果: Additional setup after loading the view.
6.判断字符串是否只包含数字
- (BOOL)validateNumber:(NSString*)number {

BOOL res = YES;

NSCharacterSet* tmpSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];

int i = 0;

while (i < number.length) {

NSString * string = [number substringWithRange:NSMakeRange(i, 1)];

NSRange range = [string rangeOfCharacterFromSet:tmpSet];

if (range.length == 0) {

res = NO;

break;

}

i++;

}

return res;

}
7.在UITextFieldDelegate方法中, 限制只能输入数字和小数点, 且第一位不可以输入小数点, 小数点只能输入一个
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

NSCharacterSet *cs;

NSUInteger nDotLoc = [textField.text rangeOfString:@"."].location;

if (NSNotFound == nDotLoc && 0 != range.location) {

cs = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789."] invertedSet];

}else{

cs = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] invertedSet];

}

NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];

BOOL basicTest = [string isEqualToString:filtered];

if (!basicTest) {

return NO;

}

return YES;

}
8.限制手机号码正确输入
if (textField == self.userNameTextField) {//限时手机号输入
        _previousTextFieldContent = textField.text;
        _previousSelection = textField.selectedTextRange;
        NSLog(@"--------- textField.text:%@,textField.selectedTextRange:%@,range:(%ld,%ld),string:%@",textField.text,textField.selectedTextRange,range.location,range.length,string);
        if (range.location == 0){
            NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:@"1"] invertedSet];
            NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
            BOOL basicTest = [string isEqualToString:filtered];
            if (!basicTest){
                //            [self showMyMessage:@"只能输入数字"];
                return NO;
            }
        }
        else if (range.location == 1) {
            NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:@"^[3,4,5,7,8]$"] invertedSet];
            NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
            BOOL basicTest = [string isEqualToString:filtered];
            if (!basicTest){
                //[self showMyMessage:@"只能输入数字"];
                return NO;
            }
        }
        if (range.location > 12) {
            return NO;
        }
    }
上一篇下一篇

猜你喜欢

热点阅读