字符串常用方法

字符串大小写方法

-(NSString *)uppercaseString:将字符全改成大写的;

  -(NSString *)lowercaseString:将字符全改成小写的;

  -(NSString *)capitalcaseString:将首个字符改成大写,其余的都小写;
           

字符串的替换函数

-(NSString *)stringByReplacingOccurrencesOfString:(NSString *)targetwithString:(NSString *)replacement:将原字符串中的所有的target替换成replacement

  -(NSString *)stringByReplaceingCharactersInRange:(NSRange)withString:(NSRange)rangewithString:(NSString *)replacement:将原字符串中range范围内的内容替换成replacement;

  -(NSArray *)componentsSeparatedByString:(NSString *)separator:以separator:以separator为分隔符,将原字符串中的内容进行分割,分割得到的结果放到一个数组里,作为返回值
           

可变字符串

初始化方法

NSMutableString *mString = [NSMutableString stringWithString:@"nihao"];

    NSMutableString *mString1 = [NSMutableString stringWithFormat:@"hello"];
    NSMutableString *mString2 = [NSMutableString stringWithContentsOfFile:@"" encoding:4 error:nil];
    NSMutableString *mString3 = [NSMutableString stringWithContentsOfURL:[NSURL URLWithString:@""] encoding:4 error:nil];
    //可变字符串独特初始化方式，初始化一个空间为100的空的可变字符串
    NSMutableString *mString4 = [[NSMutableString alloc] initWithCapacity:100];
           

2.操作(不可变字符串的API)

C 语言字符数组转换成 OC的字符串

NSString *targetString = @"你麻痹";

    NSMutableString *targetString = [NSMutableString stringWithString:@"你麻痹"];

    NSRange range = [targetString rangeOfString:@"麻痹"];

    [targetString replaceCharactersInRange:range withString:@"**"];

    NSLog(@"targetString = %@",targetString);
           

增加

在指定位置去插入一段字符串

    [targetString insertString:@",你是sb么，有点意识，OK？"   

    atIndex:targetString.length];

    NSLog(@"targetString = %@",targetString);
    在字符串的末尾添加一个字符串

    [targetString appendString:@"不想玩，滚！"];

    NSLog(@"targetString = %@",targetString);

    在字符串的末尾添加多个字符串

    [targetString appendFormat:@"%@%@",@"fuck!",@"your mom boom boom boom"];

    NSLog(@"targetString = %@",targetString);
           

替换

range = [targetString rangeOfString:@"sb"];

    [targetString replaceCharactersInRange:range withString:@"**"];

    NSLog(@"targetString = %@",targetString);
           

删除

[targetString deleteCharactersInRange:NSMakeRange(0, 3)];

     NSLog(@"targetString = %@",targetString);
           

NSArray/NSMutableArray

在OC中,我们用

NSArray

类和

NSMutableArray

类来表示数组.其中

NSArray

类是

NSMutableArray

类的父类.在oc中,我们的数组是有序的

对象

的集合,

即我们的数组只能存储’对象’.在OC中我们的数组中元素类型不能是

int

,

float

,

CGPoint

等类型.

NSArray

1初始化方法

//川建一个空的不可变的数组
    NSArray *array1=[[NSArray alloc]init];
    NSArray *array2=[NSArray array];
    //创建一个里面只有一个元素的不可变数组
    NSArray *array3=[NSArray arrayWithObject:@"zhoudu"];
    //创建一个里面有多个元素的不可变数组
    NSArray *array4=[NSArray arrayWithObjects:@"linfurong",@"xingzhenyu",@"zhuweijian",@"keyi", nil];
    NSLog(@"Hello, World!");
    //新语法
    NSArray *array5=@[@"zhoudu"];
    NSArray *array6=@[@"linfurong",@"zhuweijian",@"keyi"];
    //
   // NSArray *array7=[NSArray arrayWithArray:@""];