【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 ; }