OC4_NSString操作

//

//  main.m

//  OC4_NSString操作

//

//  Created by zhangxueming on 15/6/10.

//  Copyright (c) 2015年 zhangxueming. All rights reserved.

//



#import <Foundation/Foundation.h>



//NSString

int main(int argc, const char * argv[]) {

    @autoreleasepool {

        NSString *str1 = @"hello world 千锋";

        //求字符串长度

        NSUInteger len = [str1 length];

        NSLog(@"len = %li", len);

        //获取字符串指定位置的字符

        unichar ch = [str1 characterAtIndex:13];

        NSLog(@"ch = %C", ch);//%C打印unichar字符 %c打印ASCII字符

        

        //字符串提取

        //从传入下标位置提取子串到字符串结束

        NSString *subStr1 = [str1 substringFromIndex:4];

        NSLog(@"subStr1 = %@", subStr1);

        //提取子串到指定位置(不包含下标位置字符)

        NSString *subStr2 = [str1 substringToIndex:7];

        NSLog(@"subStr2 = %@",subStr2);

        

        //提取指定范围内的字符串

        NSRange range = {6,5};

        NSString *subStr3 = [str1 substringWithRange:range];

        NSLog(@"subStr3 = %@",  subStr3);

        

        //NSMakeRange();//构建NSRange变量

        NSString *subStr4 = [str1 substringWithRange:NSMakeRange(2, 6)];

        NSLog(@"subStr4 = %@", subStr4);

        

        //字符串比较

        NSString *str2 = [NSString stringWithCString:"hallo world中国" encoding:NSUTF8StringEncoding];

        NSString *str3 = [NSString stringWithUTF8String:"hello world中国"];

        NSComparisonResult result = [str2 compare:str3];

        if (result == NSOrderedAscending) {//递增

            NSLog(@"str2 < str3");

        }

        else if(result == NSOrderedDescending)//递减

        {

            NSLog(@"str2 > str3");

        }

        else

        {

            NSLog(@"str2 == str3");

        }

        //以大小写不敏感方式比较字符串

        //[str2 caseInsensitiveCompare:str3];

        //判断两个字符串是否相等

        //- (BOOL)isEqualToString:(NSString *)aString;

        BOOL ret = [str2 isEqualTo:str3];

        if (ret==YES) {

            NSLog(@"str2 == str3");

        }

        else

        {

            NSLog(@"str2 != str3");

        }

        //判断前缀子串

        //- (BOOL)hasPrefix:(NSString *)aString;

        BOOL ret1 = [@"www.baidu.com" hasPrefix:@"www."];

        NSLog(@"ret1 = %d", ret1);

        //判断后缀子串

        //- (BOOL)hasSuffix:(NSString *)aString;

        BOOL ret2 = [@"www.hao123.com" hasSuffix:@"com"];

        NSLog(@"ret2 = %d", ret2);

        //判断是否包含子串(10.10macos)

        BOOL ret3 = [@"hao123" containsString:@"hao"];

        NSLog(@"ret3 = %d", ret3);

        

        //查找子串

        NSString *str4 = [[NSString alloc] initWithFormat:@"%s","hello world qianworldfeng"];

        NSRange range1 =[str4 rangeOfString:@"world"];

        if (range1.location == NSNotFound) {//不能查找对应的子串, 返回long类型最大值

            NSLog(@"没有查找到字串 notfound = %lu", NSNotFound);

        }

        else

        {

            NSLog(@"location = %lu length = %lu", range1.location, range1.length);

        }

        

        //倒序查找子串

        NSRange range2 = [str4 rangeOfString:@"world" options:NSBackwardsSearch];

        NSLog(@"location = %li length = %li", range2.location, range2.length);

        

        //字符串追加

        //并不是直接在原字符串的末尾追加字符串, 而是利用传入的字符串及原字符串创建一个新的字符串

        NSString *str5 = @"hello";

        NSLog(@"%p", str5);

        str5 = [str5 stringByAppendingString:@"world"];

        NSLog(@"str5 = %@", str5);

        NSLog(@"%p", str5);

        

        //格式化追加字符串

        NSString *str6 = @"qianfeng";

        str6 = [str6 stringByAppendingFormat:@"%d%s",123,"helloworld"];

        NSLog(@"str6 = %@", str6);

        

        //把字符换串对象转换成整型 浮点型

        int a = [@"12345" intValue];

        float f = [@"3.14" floatValue];

        NSLog(@"a = %d f = %.2f", a, f);

        

        //返回公共前缀子串

        NSString *str7 = [@"www.baidu.com" commonPrefixWithString:@"www.hao123.com" options:NSLiteralSearch];

        NSLog(@"str7 = %@", str7);

        

        //大小写转换

        //把小写字母转换成大写字母

        NSString *str8 = [@"baidu中国" uppercaseString];

        NSLog(@"str8 = %@", str8);

        //把大写字母转换成小写字母

        NSString *str9 = [@"BaiDU" lowercaseString];

        NSLog(@"str9 = %@", str9);

        //把每个单词的首字母大写

        NSString *str10= [@"bai du qian feng" capitalizedString];

        NSLog(@"str10 = %@", str10);

        

        //字符串替换

        //- (NSString *)stringByReplacingOccurrencesOfString:(NSString *)target withString:(NSString *)replacement

        NSString *str11= @"hello world qianfeng hello world hello hell qianfeng";

        str11 = [str11 stringByReplacingOccurrencesOfString:@"hello" withString:@"welcome"];

        NSLog(@"str11 = %@", str11);

        

        //替换指定范围内的字符

        //- (NSString *)stringByReplacingCharactersInRange:(NSRange)range withString:(NSString *)replacement

        NSString *str12 = @"hello world qianfeng";

        str12 = [str12 stringByReplacingCharactersInRange:NSMakeRange(12, 8) withString:@"welcome"];

        NSLog(@"str12 = %@", str12);

        

        //把OC的字符串对象转换成C字符串

        NSLog(@"%s", [@"hello world" UTF8String]);

        

        //用网址的内容生成OC字符串对像

        //- (instancetype)initWithContentsOfURL:(NSURL *)url encoding:(NSStringEncoding)enc error:(NSError **)error;

        //+ (instancetype)stringWithContentsOfURL:(NSURL *)url encoding:(NSStringEncoding)enc error:(NSError **)error;

        NSURL *url= [[NSURL alloc] initWithString:@"http://www.baidu.com"];

        NSString *urlContent = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];//nil 空指针

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

        

        //用文件的内容生成字符串

        //- (instancetype)initWithContentsOfFile:(NSString *)path encoding:(NSStringEncoding)enc error:(NSError **)error;

        //+ (instancetype)stringWithContentsOfFile:(NSString *)path encoding:(NSStringEncoding)enc error:(NSError **)error;

        NSString *fileContent = [NSString stringWithContentsOfFile:@"/Users/zhangxueming/Desktop/json.txt" encoding:NSUTF8StringEncoding error:nil];

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

        

    }

    return 0;

}