【Foundation Frame】NSString

NSString代表字符序列不可变的字符串，功能更强大，更方便简单。

下面代码列举了大部分常用的NSString方法。

//
//  main.m
//  OcString
//
//  Created by mac on 14-12-2.
//  Copyright (c) 2014年 mac. All rights reserved.
//

#import <Foundation/Foundation.h>

void dynamicCreateString()
{

    //1
    NSString *str1 = @"neusoft i love you";
    NSLog(@"%@",str1);
    //2
    NSString *str2 = [[NSString alloc]init];
    [str2 release];
    //使用oc字符串付初值
    NSString *str3 = [[NSString alloc]initWithString:str1];
    NSLog(@"%@",str3);
    [str3 release];
    //使用c语言的字符串初始化
    NSString *str4 = [[NSString alloc] initWithUTF8String:"I love you"];
    NSLog(@"%@",str4);
    [str4 release];
    //格式化创建方式
    NSString *str5 = [[NSString alloc]initWithFormat:@"i am %i years old",10];
    NSLog(@"%p, %@",str5,str5);
    //[str5 release];
   
    NSString *str6 =  [str5 stringByAppendingString:str1];
    NSLog(@"%p, %@",str6,str6);
    [str5 release];
    [str6 release];
   
    //使用文件初始化
    NSError * error;
    NSString *str7 = [[NSString alloc]initWithContentsOfFile:@"/Users/mac/Desktop/a.txt" encoding:NSUTF8StringEncoding error:&error];
    NSLog(@"%@, %@",str7,error);
   
    NSString * path = @"file:///Users/mac/Desktop/a.txt";
    NSString * httpContents = @"http://people.com.cn";

   
    NSURL * url = [NSURL URLWithString:httpContents];
    NSString *str8 = [[NSString alloc]initWithContentsOfURL:url encoding:CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000) error:&error];
    NSLog(@"%@, %@",str8,error);
    [str8 release];
   
   
}

void staticCreateString()
{
    NSString * str1 = [NSString stringWithFormat:@"i am %i years old",10];
    NSLog(@"%@",str1);
}

#pragma mark  导出到文件中

void export()
{
   
    //向文件中写入，持久化的过程
    NSString * str = @"i was a child , i have a dreamer ";
    NSString * path = @"file:///Users/mac/Desktop/a.txt";

    NSError *error;
    [str writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error];
   
    NSLog(@"%@",error);
   
    NSURL * url = [NSURL URLWithString:path];
    [str writeToURL:url atomically: YES encoding:NSUTF8StringEncoding error:&error];
   NSLog(@"%@",error);
   
}


void otherMethord()
{
    //请求字符串长度
    NSLog(@"%lu",[@"abcd吴剑光" length]);
    NSLog(@"%c",[@"abcd吴剑光" characterAtIndex:3]);
   
}


void caseMethord()
{
    NSString * str = @"I'am  boY ,i have a dream";
   
    NSLog(@"%@",[str uppercaseString]);
    NSLog(@"%@",[str lowercaseString]);
    NSLog(@"%@",[str capitalizedString]);
   
}


void campareWithString()
{
    NSString * str = @"Z'am  boY ,i have a dream";
    NSString * str1 = @"I'am  boY ,i have a dream";
   
    if ([str isEqualToString:str1]) {
        NSLog(@"true");
    }
   
    NSLog(@"%li",[str compare:str1]);
   
}

void searchString()
{
    NSString * str = @"neuZ'am  boY ,i have a dream";
    NSLog(@"%i",[str hasPrefix:@"neu"]);
    NSLog(@"%i",[str hasSuffix:@"exm"]);
   
    NSRange range1 = [str rangeOfString:@"have"];
    NSLog(@"%lu,%lu",range1.location,range1.length);
   
   
    NSRange range2 = [str rangeOfString:@"have" options:NSBackwardsSearch];
    NSLog(@"%lu,%lu",range2.location,range2.length);
   
}

void subString()
{
    NSString * str = @"neuZ'am #boY #i have# a dream";
    NSLog(@"%@", [str substringFromIndex:3]);
    NSLog(@"%@", [str substringToIndex:3]);
    NSLog(@"%@",  [str substringWithRange:NSMakeRange(3, 5)]);
    NSArray * array = [str componentsSeparatedByString:@"#"];
    NSLog(@"%@",array);
   
   
}

void pathString()
{
   
    NSString * str = @"neuZ'am #boY #i have# a dream";
    NSArray * array = [str componentsSeparatedByString:@"#"];
    NSLog(@"%@", [NSString pathWithComponents:array]);
   
    NSString * path = @"Users/mac/desktop";
    NSLog(@"%@", [path pathComponents]);
   
    NSLog(@"%i", [path isAbsolutePath]);
   
    NSLog(@"%@", [path stringByAppendingPathComponent:@"abc"]);
   
    NSLog(@"%@", path);
   
}

void extentionString()
{
    NSString * path = @"/Users/mac/Desktop/a.txt";
    NSLog(@"%@", [path pathExtension]);
    NSLog(@"%@", [path stringByDeletingPathExtension]);
    NSLog(@"%@", [path stringByAppendingPathExtension:@"xml"]);
}

void exchangeType()
{
    NSString *str1 = @"234.2342424";
    NSString *str2 = @"234.45";
    NSString *str3 = @"234";
    NSString *str4 = @"abcde";
   
    NSLog(@"%f",[str1 doubleValue]);
    NSLog(@"%f",[str2 floatValue]);
    NSLog(@"%i",[str3 intValue]);
    NSLog(@"%s",[str4 UTF8String]);
   
}

#pragma mark NSMutableString
void mutableStringOperation()
{
    NSMutableString * str = [NSMutableString stringWithCapacity:10];
    [str setString:@"i was girl"];
    NSLog(@"%@", str);
    [str appendFormat:@" %i years old", 10];
    NSLog(@"%@", str);
    [str replaceCharactersInRange:NSMakeRange(2, 3) withString:@"abcdekfslfj"];
    NSLog(@"%@", str);


}
int main(int argc, const char * argv[]) {
   
    @autoreleasepool {
      
        mutableStringOperation();
       
        exchangeType();
        extentionString();
       
        pathString();
        subString();
        searchString();
        dynamicCreateString();
        staticCreateString();
       
        export() ;
       
        otherMethord();
        caseMethord();
       
        campareWithString();
    }
    return 0;

}