OC基础之NSString

本文对OC的NSString类的方法属性做了一个全面的测试，完全是基础，没兴趣的就不用看这个浪费时间了：

//
//  string.m
//  GVRegularExpressionDemo
//
//  Created by gavin on 15/8/29.
//  Copyright (c) 2015年 GV. All rights reserved.
//

#import "string.h"
#import <Foundation/NSPropertyList.h>

@implementation string

-(void)stringTest{

#pragma mark NSString

    NSString *str = [NSString stringWithFormat:@"NSString Test..."];
    NSLog(@"%@",str);
    NSStringEncoding encode;

    /////////////////////  Creating and Initializing Strings   /////////////////////

    const char* chs = "gavinZhang";
    unichar unichs[] = {'g','a','v','i','n','Z','h','a','n','g','1'};


    // + string //empty string.
    NSLog(@"%d",(int)[[NSString string] length]);

    // -init
    NSLog(@"%d",(int)[[[NSString alloc] init] length]);

    // - initWithBytes:length:encoding:
    str = [[NSString alloc] initWithBytes:chs length:5 encoding:NSUTF8StringEncoding];
    NSLog(@"str = %@",str);

    // - initWithBytesNoCopy:length:encoding:freeWhenDone:
    NSData *aData = [NSData dataWithBytes:chs length:strlen(chs)];
    Byte *byte = (Byte*)[aData bytes];
    Byte *buffer = malloc(strlen(chs));
    memccpy(buffer, byte, 0, strlen(chs));
    str = [[NSString alloc] initWithBytesNoCopy:(void *)byte length:strlen(chs) encoding:NSUTF8StringEncoding freeWhenDone:NO];
    NSLog(@"str = %@", str);
    str = [[NSString alloc] initWithBytesNoCopy:(void *)buffer length:strlen(chs)-1 encoding:NSUTF8StringEncoding freeWhenDone:YES];
    NSLog(@"str = %@", str);
    //此行会产生crash, 因为上一次指定freeWhenDone为yes后, buffer已经被释放;
    //str = [[NSString alloc] initWithBytesNoCopy:(void *)buffer length:strlen(chs)-1 encoding:NSUTF8StringEncoding freeWhenDone:YES];
    //NSLog(@"str = %@", str);


    // - initWithCharacters:length:
    str = [[NSString alloc] initWithCharacters:unichs length:3];
    NSLog(@"str = %@", str);

    // - initWithCharactersNoCopy:length:freeWhenDone:
    str = [[NSString alloc] initWithCharactersNoCopy:unichs length:sizeof(unichs)/sizeof(unichs[0]) freeWhenDone:NO];
    NSLog(@"str = %@", str);

    // - initWithString:
    NSLog(@"%p",str);
    str = [[NSString alloc] initWithString:str];
    NSLog(@"%p",str);
    NSLog(@"%@", str);

    // - initWithCString:encoding:
    str = [[NSString alloc] initWithCString:chs encoding:NSUTF8StringEncoding];
    NSLog(@"%@", str);

    // - initWithUTF8String:
    str = [[NSString alloc] initWithUTF8String:chs];
    NSLog(@"%@", str);

    // - initWithFormat:arguments:
    str = [self vaListTest:@"gavin",@" Zhang",@" va_list",@" test"];
    NSLog(@"str = %@",str);

    // - initWithFormat:locale:
    str = [[NSString alloc] initWithFormat:@"%@" locale:[NSLocale currentLocale], @"gavinZhang_NSLocale"];
    NSLog(@"str = %@",str);

    // - initWithFormat:locale:arguments:
    str = [self vaListTest:@"gavin",@" Zhang",@" va_list",@" test"];
    NSLog(@"str = %@",str);

    // - initWithData:encoding:
    NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];
    str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    NSLog(@"str = %@",str);

    // + stringWithFormat: // - initWithFormat:
    str = [[NSString alloc] initWithFormat:@"gavin%@",@"Zhang" ];
    NSLog(@"str = %@",str);
    str = [NSString stringWithFormat:@"gavin%@",@"Zhang2"];
    NSLog(@"str = %@",str);

    // + localizedStringWithFormat: //This method is equivalent to using initWithFormat:locale: and passing the current locale as the locale argument.
    str = [NSString localizedStringWithFormat:@"%@",@"stringTest"];
    NSLog(@"str = %@",str);

    // + stringWithCharacters:length:
    str = [NSString stringWithCharacters:unichs length:sizeof(unichs)/sizeof(unichs[0])];
    NSLog(@"str = %@",str);


    // + stringWithString:
    NSLog(@"str.address = %p",str);
    str = [NSString stringWithString:str];
    NSLog(@"str.address = %p",str);

    //+ stringWithCString:encoding:
    str = [NSString stringWithCString:chs encoding:NSUTF8StringEncoding];
    NSLog(@"str = %@",str);

    // + stringWithUTF8String:
    str = [NSString stringWithUTF8String:chs];
    NSLog(@"str = %@",str);

    //////////////////////////  Creating and Initializing a String from a File   //////////////////////////

    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"test.txt"];
    NSLog(@"path = %@",path);
    [str writeToFile:path atomically:NO encoding:NSUTF8StringEncoding error:nil];

    // + stringWithContentsOfFile:encoding:error:
    NSError *error = nil;
    str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];
    if (!error) {
        NSLog(@"str = %@, error = %@",str,error);
    }else{
        NSLog(@"error = %@", error);
    }

    //  - initWithContentsOfFile:encoding:error:
    //如果你想在缺少编码信息的情况下,猜出编码,可以使用stringWithContentsOfFile:usedEncoding:error:或者 initWithContentsOfFile:usedEncoding:error: 方法
    str = [[NSString alloc] initWithContentsOfFile:path usedEncoding:&encode  error:&error];
    NSLog(@"str = %@, error = %@, encode = %d",str,error,(int)encode);

    // + stringWithContentsOfFile:usedEncoding:error:
    str = [NSString stringWithContentsOfFile:path usedEncoding:&encode error:nil];
    NSLog(@"str = %@, error = %@, encode = %d",str,error,(int)encode);



    ////////////////////////// Creating and Initializing a String from an URL //////////////////////////

    // + stringWithContentsOfURL:encoding:error:
    //远程
    NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
    str = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"str.lentgh = %ld, error = %@, encode = %d",str.length,error,(int)encode);
    //本地
    url = [NSURL URLWithString:[NSString stringWithFormat:@"file://%@",path]];
    str = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"str = %@, error = %@, path = %@, url = %@" ,str, error, path, url);

    // - initWithContentsOfURL:encoding:error:
    str = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"str = %@, error = %@, path = %@, url = %@" ,str, error, path, url);

    // + stringWithContentsOfURL:usedEncoding:error:

    str = [NSString stringWithContentsOfURL:url usedEncoding:&encode error:nil];
    NSLog(@"str = %@, error = %@, path = %@, usedEncoding = %d, url = %@" ,str, error, path, (int)encode, url);

    // - initWithContentsOfURL:usedEncoding:error:
    str = [[NSString alloc] initWithContentsOfURL:url usedEncoding:&encode error:nil];
    NSLog(@"str = %@, error = %@, path = %@, usedEncoding = %d, url = %@" ,str, error, path, (int)encode, url);


    ////////////////////////// Writing to a File or URL //////////////////////////

    // - writeToFile:atomically:encoding:error:
    [str writeToFile:path atomically:NO encoding:NSUTF8StringEncoding error:&error];
    if (error) {
        NSLog(@"error = %@",error);
    }else{
        str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
        NSLog(@"str1 = %@, error = %@",str, error);
    }

    // - writeToURL:atomically:encoding:error:
    [str writeToURL:url atomically:NO encoding:NSUTF8StringEncoding error:&error];
    if (!error) {
        NSLog(@"str2 = %@, error = %@",str, error);
    }

    ////////////////////////// Getting a String’s Length //////////////////////////

    //length Property
    NSLog(@"str.length = %d", (int)str.length);

    // - lengthOfBytesUsingEncoding: //当用enc对字符串进行编码时，用于存储数组所需要的字节数。
    str = @"张先生";
    int length = (int)str.length;
    int unicodeLen = (int)[str lengthOfBytesUsingEncoding:NSUnicodeStringEncoding];
    int utf8Len = (int)[str lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
    int utf16Len = (int)[str lengthOfBytesUsingEncoding:NSUTF16StringEncoding];
    int utf32Len = (int)[str lengthOfBytesUsingEncoding:NSUTF32StringEncoding];
    NSLog(@"length = %d, utf16Len = %d = unicodeLen = %d, utf8Len = %d, utf32Len = %d", length, utf16Len, unicodeLen, utf8Len, utf32Len);

    // - maximumLengthOfBytesUsingEncoding: //返回当用enc对字符串进行编码存储时，所需要的最大字节数。
    str = @"a哈哈哈";
    NSLog(@"\n\nlength = %ld", str.length);
    NSLog(@"utf16Len = %d", (int)[str maximumLengthOfBytesUsingEncoding:NSUTF16StringEncoding]);
    NSLog(@"unicodeLen = %d", (int)[str maximumLengthOfBytesUsingEncoding:NSUnicodeStringEncoding]);
    NSLog(@"utf8Len = %d", (int)[str maximumLengthOfBytesUsingEncoding:NSUTF8StringEncoding]);
    NSLog(@"utf32Len = %d", (int)[str maximumLengthOfBytesUsingEncoding:NSUTF32StringEncoding]);


    ////////////////////////// Getting Characters and Bytes //////////////////////////

    // - characterAtIndex:
    str = @"gavin";
    NSLog(@"\n\n [str characterAtIndex:0]: %c",[str characterAtIndex:0]);

    // - getCharacters:range:
    str = @"gavinZhang";
    unichar *buffer2 = malloc(10);
    [str getCharacters:buffer2 range:NSMakeRange(0, 10)];
    NSLog(@"[str getCharacters:buffer2 range:NSMakeRange(0, 10)] : %S", (const unichar*)buffer2);
    free(buffer2);

    // - getBytes:maxLength:usedLength:encoding:options:range:remainingRange:
    NSData *strData = [str dataUsingEncoding:NSUnicodeStringEncoding allowLossyConversion:YES];
    NSUInteger dataLength = [strData length];
    Byte *byteData = (Byte*)malloc( dataLength );
    memcpy( byteData, [strData bytes], dataLength );

    NSUInteger numberOfBytes = [str lengthOfBytesUsingEncoding:NSUnicodeStringEncoding];
    void *buffer3 = malloc(numberOfBytes);
    bzero(buffer3, numberOfBytes);
    NSUInteger usedLength = 0;
    NSRange range = NSMakeRange(0, [str length]);
    BOOL result = [str getBytes:buffer3 maxLength:numberOfBytes usedLength:&usedLength encoding:NSUnicodeStringEncoding options:0 range:range remainingRange:NULL];
    NSLog(@"buffer3 = %S, result = %d, usedLength = %ld",(const unichar*)buffer3, result, usedLength);
    str = [NSString stringWithFormat:@"%S",(const unichar*)buffer3];
    NSLog(@"buffer3 to nsstring -> %@", str);
    free(buffer3);

    ////////////////////////// Getting C Strings //////////////////////////

    // - cStringUsingEncoding:
    const char *chs2 = [str cStringUsingEncoding:NSASCIIStringEncoding];
    NSLog(@"chs2%%s = %s, chs2%%S = %S", chs2, (const unichar*)chs2);

    chs2 = [str cStringUsingEncoding:NSUnicodeStringEncoding];
    NSLog(@"chs2%%s = %s, chs2%%S = %S", chs2, (const unichar*)chs2);

    // - getCString:maxLength:encoding:
    str = @"gavinZhang";
    char buffer4[512];
    result = [str getCString:buffer4 maxLength:512 encoding:NSUnicodeStringEncoding];
    if (result) {
        NSLog(@"buffer4 = %S",(const unichar*)buffer4);
    }

    // UTF8String Property
    const char *str3 = [str UTF8String];
    NSLog(@"str3 = %s",str3);


    ////////////////////////// Combining Strings //////////////////////////

    // - stringByAppendingFormat:
    str = [str stringByAppendingFormat:@" hello%@",@"!"];
    NSLog(@"str = %@", str);

    // - stringByAppendingString:
    str = [str stringByAppendingString:@"!"];
    NSLog(@"str = %@", str);

    // - stringByPaddingToLength:withString:startingAtIndex:
    str = [str stringByPaddingToLength:str.length withString:@"_instert_" startingAtIndex:2];
    NSLog(@"str = %@", str);


    ////////////////////////// Dividing Strings //////////////////////////

    // - componentsSeparatedByString:
    str = @"Gavin Zhang hello";
    NSArray *arr = [str componentsSeparatedByString:@" "];
    NSLog(@"arr = %@", arr);

    // - componentsSeparatedByCharactersInSet:
    arr = [str componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"a "]];
    NSLog(@"arr = %@", arr);

    // - stringByTrimmingCharactersInSet: //在字符串的首或尾、删除字符集合组成的字符串
    NSString *str2 = [str stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"lohe"]];
    NSLog(@"str2 = %@", str2); //结果: str2 = Gavin Zhang

    // - substringFromIndex:
    str2 = [str substringFromIndex:6];
    NSLog(@"str2 = %@", str2);

    // - substringWithRange:
    str2 = [str substringWithRange:NSMakeRange(0, 5)];
    NSLog(@"str2 = %@", str2);

    // - substringToIndex:
    str2 = [str substringToIndex:8];
    NSLog(@"str2 = %@", str2);


    ////////////////////////// Finding Characters and Substrings //////////////////////////

    // - rangeOfCharacterFromSet: //从头向尾查找, 直到找到第一个字符为至.
    NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"In"];
    range = [str rangeOfCharacterFromSet:set];
    NSLog(@"range = %@, str = %@",NSStringFromRange(range),str);

    // - rangeOfCharacterFromSet:options:

    // options:(NSStringCompareOptions)
    // enum{
    // NSCaseInsensitiveSearch = 1,//不区分大小写比较
    // NSLiteralSearch = 2,//区分大小写比较
    // NSBackwardsSearch = 4,//从字符串末尾开始搜索
    // NSAnchoredSearch = 8,//搜索限制范围的字符串
    // NSNumbericSearch = 64//按照字符串里的数字为依据，算出顺序。例如 Foo2.txt < Foo7.txt < Foo25.txt
    // //以下定义高于 mac os 10.5 或者高于 iphone 2.0 可用
    // NSDiacriticInsensitiveSearch = 128,//忽略 "-" 符号的比较
    // NSWidthInsensitiveSearch = 256,//忽略字符串的长度，比较出结果
    // NSForcedOrderingSearch = 512//忽略不区分大小写比较的选项，并强制返回 NSOrderedAscending 或者 NSOrderedDescending
    // //以下定义高于 iphone 3.2 可用
    // NSRegularExpressionSearch = 1024//只能应用于 rangeOfString:..., stringByReplacingOccurrencesOfString:...和 replaceOccurrencesOfString:... 方法。使用通用兼容的比较方法，如果设置此项，可以去掉 NSCaseInsensitiveSearch 和 NSAnchoredSearch
    // }
    set = [NSCharacterSet characterSetWithCharactersInString:@"In"];
    range = [str rangeOfCharacterFromSet:set options:NSBackwardsSearch];
    NSLog(@"range = %@, str = %@",NSStringFromRange(range),str);

    // - rangeOfCharacterFromSet:options:range:
    range = [str rangeOfCharacterFromSet:set options:NSBackwardsSearch range:NSMakeRange(0, str.length)];
    NSLog(@"range = %@, str = %@",NSStringFromRange(range),str);

    // - rangeOfString:
    range = [str rangeOfString:@"Zhang"];
    NSLog(@"range = %@, str = %@",NSStringFromRange(range),str);

    // - rangeOfString:options:
    range = [str rangeOfString:@"in" options:0 range:NSMakeRange(0, str.length) locale:[NSLocale currentLocale]];
    NSLog(@"range = %@, str = %@",NSStringFromRange(range),str);

    // - enumerateLinesUsingBlock:
    str = @"Gavin \n Zhang \n Hello!";
    [str enumerateLinesUsingBlock:^(NSString *line, BOOL *stop) {
        NSLog(@"line = %@, BOOL = %d",line, (int)stop);
        if ([line rangeOfString:@"zhang" options:NSCaseInsensitiveSearch].location != NSNotFound) {
            *stop = YES; //return;
        }
    }];


    // - enumerateSubstringsInRange:options:usingBlock:

    //typedef NS_OPTIONS(NSUInteger, NSStringEnumerationOptions) {
    //    // Pass in one of the "By" options:
    //    NSStringEnumerationByLines = 0,                       // Equivalent to lineRangeForRange:
    //    NSStringEnumerationByParagraphs = 1,                  // Equivalent to paragraphRangeForRange:
    //    NSStringEnumerationByComposedCharacterSequences = 2,  // Equivalent to rangeOfComposedCharacterSequencesForRange:
    //    NSStringEnumerationByWords = 3,
    //    NSStringEnumerationBySentences = 4,
    //    // ...and combine any of the desired additional options:
    //    NSStringEnumerationReverse = 1UL << 8,
    //    NSStringEnumerationSubstringNotRequired = 1UL << 9,
    //    NSStringEnumerationLocalized = 1UL << 10              // User's default locale
    //};

    [str enumerateSubstringsInRange:NSMakeRange(0, str.length) options:NSStringEnumerationByLines usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
        NSLog(@"substring = %@, substringRange = %@, enclosingRange = %@",
              substring, NSStringFromRange(substringRange), NSStringFromRange(enclosingRange));
    }];


    ////////////////////////// Replacing Substrings //////////////////////////

    // - stringByReplacingOccurrencesOfString:withString:options:range:
    str = @"Gavin Zhang";
    str = [str stringByReplacingOccurrencesOfString:@"zhang" withString:@"Li" options:NSCaseInsensitiveSearch range:NSMakeRange(0, str.length)];
    NSLog(@"str = %@", str);

    // - stringByReplacingCharactersInRange:withString:
    str = [str stringByReplacingCharactersInRange:NSMakeRange(0, str.length) withString:@"Ta"];
    NSLog(@"str = %@", str);


    ////////////////////////// Determining Line and Paragraph Ranges //////////////////////////

    // - getLineStart:end:contentsEnd:forRange:  //PS: OC 里用这种方式返回多个值。
    str = @"Gavin \n Zhang \n Hello!";
    NSUInteger s, e, ce;
    [str getLineStart:&s end:&e contentsEnd:&ce forRange:NSMakeRange(0, 1)];
    NSLog(@"str = \n%@, s = %ld, e = %ld, ce = %ld, str.length = %ld", str, s, e, ce, str.length);

    // - lineRangeForRange:
    range = [str lineRangeForRange:NSMakeRange(0, 1)];
    NSLog(@"range = %@", NSStringFromRange(range));

    // - getParagraphStart:end:contentsEnd:forRange:
    [str getParagraphStart:&s end:&e contentsEnd:&ce forRange:NSMakeRange(0, 1)];
    NSLog(@"str = \n%@, s = %ld, e = %ld, ce = %ld, str.length = %ld", str, s, e, ce, str.length);

    // - paragraphRangeForRange:
    range = [str paragraphRangeForRange:NSMakeRange(0, 1)];
    NSLog(@"range = %@", NSStringFromRange(range));


    ////////////////////////// Determining Composed Character Sequences(测试了很久不知道实际用途????) //////////////////////////

    //- rangeOfComposedCharacterSequenceAtIndex:
    range = [str rangeOfComposedCharacterSequenceAtIndex:8];
    NSLog(@"range = %@", NSStringFromRange(range));

    //- rangeOfComposedCharacterSequencesForRange:
    range = [str rangeOfComposedCharacterSequencesForRange:NSMakeRange(8, 5)];
    NSLog(@"range = %@", NSStringFromRange(range));


    str = @"THUMB大S UP SIGN";
    //str = @"今天天气(qi)很好";
    NSLog(@"str.length = %ld", str.length);

    for (int i=0; i<str.length; ++i) {
        unichar ch = [str characterAtIndex:i];
        NSLog(@"ch = %C, i = %d\n", ch, i);
    }

    printf("\n");

    NSRange r;
    for(int i=0; i<str.length; i+=r.length){
        r = [str rangeOfComposedCharacterSequenceAtIndex:i];
        NSString *s = [str substringWithRange:r];
        NSLog(@"i = %d, s = %@", i, s);
    }

    ////////////////////////// Converting String Contents Into a Property List //////////////////////////
    NSString *str4 =
    @"<dict>"
    @"<key>CFBundleDevelopmentRegion</key>"
    @"<string>en</string>"
    @"<key>CFBundleExecutable</key>"
    @"<string>$(EXECUTABLE_NAME)</string>"
    @"<key>CFBundleIdentifier</key>"
    @"<string>com.$(PRODUCT_NAME:rfc1034identifier)</string>"
    @"<key>CFBundleInfoDictionaryVersion</key>"
    @"<string>6.0</string>"
    @"<key>CFBundleName</key>"
    @"<string>$(PRODUCT_NAME)</string>"
    @"<key>CFBundlePackageType</key>"
    @"<string>APPL</string>"
    @"<key>CFBundleShortVersionString</key>"
    @"<string>1.0</string>"
    @"<key>CFBundleSignature</key>"
    @"<string>????</string>"
    @"<key>CFBundleVersion</key>"
    @"<string>1</string>"
    @"<key>LSRequiresIPhoneOS</key>"
    @"<true/>"
    @"<key>UILaunchStoryboardName</key>"
    @"<string>LaunchScreen</string>"
    @"<key>UIMainStoryboardFile</key>"
    @"<string>Main</string>"
    @"<key>UIRequiredDeviceCapabilities</key>"
    @"<array>"
    @"<string>armv7</string>"
    @"</array>"
    @"<key>UISupportedInterfaceOrientations</key>"
    @"<array>"
    @"<string>UIInterfaceOrientationPortrait</string>"
    @"<string>UIInterfaceOrientationLandscapeLeft</string>"
    @"<string>UIInterfaceOrientationLandscapeRight</string>"
    @"</array>"
    @"</dict>";

    NSLog(@"str4 = %@",str4);

    // - propertyList //返回多种类型
    id pl = [str4 propertyList];
    NSLog(@"[str propertyList] = %@", pl);

    // - propertyListFromStringsFileFormat //仅字典类型
    pl = [str4 propertyListFromStringsFileFormat];
    NSLog(@"[str propertyListFromStringsFileFormat] = %@", pl);


    str4 =
    @"/* Question in confirmation panel for quitting. */"
    @"\"Confirm Quit\" = \"Are you sure you want to quit?\";"
    @""
    @"/* Message when user tries to close unsaved document */"
    @"\"Close or Save\" = \"Save changes before closing?\";"
    @""
    @"/* Word for Cancel */"
    @"\"Cancel\";";

    NSLog(@"str4 = %@", str4);

    pl = [str4 propertyList];
    NSLog(@"[str propertyList] = %@", pl);

    pl = [str4 propertyListFromStringsFileFormat];
    NSLog(@"[str propertyListFromStringsFileFormat] = %@", pl);


    ////////////////////////// Identifying and Comparing Strings //////////////////////////

    //- caseInsensitiveCompare:
    str = @"GavinZhang";
    NSComparisonResult cmpResult = [str caseInsensitiveCompare:@"gavinzhang"];
    NSLog(@"cmpResult = %ld", cmpResult);

    //- localizedCaseInsensitiveCompare: //应用场景??????
    cmpResult = [str localizedCaseInsensitiveCompare:@"gavinzhang"];
    NSLog(@"cmpResult = %ld", cmpResult);


    //- compare:
    NSLog(@"compare: %ld", [str compare:@"f"]);
    NSLog(@"compare: %ld", [str compare:@"GavinZhang"]);
    NSLog(@"compare: %ld", [str compare:@"h"]);

    //- localizedCompare:
    NSLog(@"localizedCompare: %ld", [str localizedCompare:@"f"]);
    NSLog(@"localizedCompare: %ld", [str localizedCompare:@"GavinZhang"]);
    NSLog(@"localizedCompare: %ld", [str localizedCompare:@"h"]);

    //- compare:options:
    //- compare:options:range:
    //- compare:options:range:locale:
    cmpResult = [str compare:@"gavinzhang" options:NSCaseInsensitiveSearch range:NSMakeRange(0, str.length) locale:[NSLocale currentLocale]];
    NSLog(@"cmpResult = %ld", cmpResult);

    //- localizedStandardCompare: //尽量用于文件名或序列表等, 使用当前的语言环境.
    cmpResult = [str localizedStandardCompare:@"gavinzhang"];
    NSLog(@"cmpResult = %ld", cmpResult);

    //- hasPrefix:
    //- hasSuffix:
    NSLog(@"str: %@, hasPrefix: %d, hasSuffix: %d", str, [str hasPrefix:@"gavin"], [str hasSuffix:@"zhang"]); //看结果是不区分大小写的.

    //- isEqualToString:
    NSLog(@"isEqualToString: %@", [str isEqualToString:@"Gavin"] ? @"YES":@"NO");

    //hash Property
    NSLog(@"hash Property: %ld", [str hash]);


    ////////////////////////// Folding Strings //////////////////////////

    // - stringByFoldingWithOptions:locale:  //Folding Strings 折叠字符串, 暂未接触到.
    str4 = [str stringByFoldingWithOptions:NSLiteralSearch locale:[NSLocale currentLocale]];
    NSLog(@"str4 = %@", str4);


    ////////////////////////// Getting a Shared Prefix //////////////////////////

    // - commonPrefixWithString:options: //包含前缀
    str4 = [str commonPrefixWithString:@"g" options:NSCaseInsensitiveSearch];
    NSLog(@"str4 = %@", str4); //结果g


    ////////////////////////// Changing Case //////////////////////////

    //capitalizedString Property
    //- capitalizedStringWithLocale:
    str = @"gavin Zhang";
    NSLog(@"capitalizedString: %@,  %@",str.capitalizedString, [str capitalizedStringWithLocale:[NSLocale currentLocale]]); //Gavin Zhang

    //lowercaseString Property
    //- lowercaseStringWithLocale:
    NSLog(@"lowercaseString: %@, %@",str.lowercaseString, [str lowercaseStringWithLocale:[NSLocale currentLocale]]);

    //uppercaseString Property
    //- uppercaseStringWithLocale:
    NSLog(@"uppercaseString: %@, %@",str.uppercaseString, [str uppercaseStringWithLocale:[NSLocale currentLocale]]);


    ////////////////////////// Getting Strings with Mapping //////////////////////////

    //decomposedStringWithCanonicalMapping Property //Unicode Normalization Form D
    //decomposedStringWithCompatibilityMapping Property //Unicode Normalization Form KD
    //precomposedStringWithCanonicalMapping Property //Unicode Normalization Form C
    //precomposedStringWithCompatibilityMapping Property //Unicode Normalization Form KC
    NSLog(@"decomposedStringWithCanonicalMapping: %@", [str decomposedStringWithCanonicalMapping]);
    NSLog(@"decomposedStringWithCompatibilityMapping: %@", [str decomposedStringWithCompatibilityMapping]);
    NSLog(@"precomposedStringWithCanonicalMapping: %@", [str precomposedStringWithCanonicalMapping]);
    NSLog(@"precomposedStringWithCompatibilityMapping: %@", [str precomposedStringWithCompatibilityMapping]);

    ////////////////////////// Getting Numeric Values //////////////////////////

    //doubleValue Property
    //floatValue Property
    //intValue Property
    //integerValue Property
    //longLongValue Property
    //boolValue Property
    double strDouble = [@"a1" doubleValue];
    float strFloat = [@"1a" floatValue];
    int strInt = [@"1" intValue];
    long strLong = [@"1" longLongValue];
    BOOL strBool = [@"2" boolValue];
    NSLog(@"strDouble = %lf, strFloat = %f, strInt = %d, strLong = %ld, strBool = %d",strDouble, strFloat, strInt, strLong, strBool);


    ////////////////////////// Working with Encodings //////////////////////////

    str = @"GavinZhang";

    //+ availableStringEncodings
    const NSStringEncoding *cs = [NSString availableStringEncodings];
    NSLog(@"availableStringEncodings: %ld", *cs); //NSMacOSRomanStringEncoding

    //+ defaultCStringEncoding //很少用.
    NSStringEncoding senc = [NSString defaultCStringEncoding];
    NSLog(@"defaultCStringEncoding: %ld", senc);

    //+ localizedNameOfStringEncoding:
    NSLog(@"localizedNameOfStringEncoding: %@", [NSString localizedNameOfStringEncoding:NSUnicodeStringEncoding]); //Unicode (UTF-16)

    //- canBeConvertedToEncoding:
    str = @"张先生";
    NSLog(@"canBeConvertedToEncoding: %@", [str canBeConvertedToEncoding:NSASCIIStringEncoding] ? @"YES":@"NO");
    str = @"GavinZhang";
    NSLog(@"canBeConvertedToEncoding: %@", [str canBeConvertedToEncoding:NSASCIIStringEncoding] ? @"YES":@"NO");

    //- dataUsingEncoding: //无损转换
    //- dataUsingEncoding:allowLossyConversion: //可以删除可修改
    str = @"张先生";
    strData = [str dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
    NSLog(@"strData = %@, strData.length = %ld", strData, strData.length);

    //description Property  //This NSString object. (read-only)
    //fastestEncoding Property //最快编码
    //smallestEncoding Property //最小编码
    NSLog(@"str.description = %@", str.description);
    NSLog(@"str.fastestEncoding = %ld", str.fastestEncoding);
    NSLog(@"str.smallestEncoding = %ld", str.smallestEncoding);
    strData = [str dataUsingEncoding:NSUnicodeStringEncoding allowLossyConversion:YES];
    str4 = [[NSString alloc] initWithData:strData encoding:NSUnicodeStringEncoding];
    NSLog(@"str4 = %@", str4);

    ////////////////////////// Working with Paths //////////////////////////

    //+ pathWithComponents:
    //pathComponents Property
    arr = @[@"a",@"//b",@"c",@"d"];
    str = [NSString pathWithComponents:arr];
    NSLog(@"str = %@", str); //print: a/b/c/d

    arr = str.pathComponents;
    NSLog(@"arr = %@", arr);

    //- completePathIntoString:caseSensitive:matchesIntoArray:filterTypes: //查找磁盘上的文件, 可指定查找类型
    //create file
    NSString *f1 = [NSHomeDirectory() stringByAppendingPathComponent:@"a.txt"];
    NSString *f2 = [NSHomeDirectory() stringByAppendingPathComponent:@"aa.txt"];
    [str writeToFile:f1 atomically:NO encoding:NSUTF8StringEncoding error:nil];
    [str writeToFile:f2 atomically:NO encoding:NSUTF8StringEncoding error:nil];

    //find file
    NSString *partialPath = [NSHomeDirectory() stringByAppendingPathComponent:@"a"];
    NSArray *outputArray;
    NSArray *filterTypes = @[@"txt", @"rtf"];
    NSString *outputName;
    NSUInteger textMatches = [partialPath completePathIntoString:&outputName
                                                 caseSensitive:NO
                                              matchesIntoArray:&outputArray
                                                   filterTypes:filterTypes];

    NSLog(@"outputArray = %@, outputName = %@, textMatches = %ld",outputArray, outputName, textMatches);


    //fileSystemRepresentation Property //CStyle string
    str = outputArray[0];
    NSLog(@"str.fileSystemRepresentation = %s", str.fileSystemRepresentation);

    //- getFileSystemRepresentation:maxLength:
    char fileCStyle[512];
    BOOL boolV = [str getFileSystemRepresentation:fileCStyle maxLength:19]; //maxLength <= 实际字符串长度时  可能会失败.
    NSLog(@"str.length = %ld, str.fileSystemRepresentation = %s, boolV = %d", str.length, fileCStyle, boolV);

    //absolutePath Property
    NSLog(@"str.absolutePath = %@", str.absolutePath ? @"YES":@"NO");

    //lastPathComponent Property
    NSLog(@"str.lastPathComponent = %@", str.lastPathComponent);

    //pathExtension Property
    NSLog(@"str.pathExtension = %@", str.pathExtension);

    //stringByAbbreviatingWithTildeInPath Property
    NSLog(@"str.stringByAbbreviatingWithTildeInPath = %@", str.stringByAbbreviatingWithTildeInPath); // ~/a.txt

    //- stringByAppendingPathComponent:
    //- stringByAppendingPathExtension:
    str = [str stringByAppendingPathComponent:@"a.txt"];
    str = [str stringByAppendingPathExtension:@"txt"];
    NSLog(@"str = %@",str);

    //stringByDeletingLastPathComponent Property
    //stringByDeletingPathExtension Property
    str = [str stringByDeletingPathExtension];
    str = [str stringByDeletingLastPathComponent];
    NSLog(@"str = %@",str);

    //stringByExpandingTildeInPath Property
    str = str.stringByAbbreviatingWithTildeInPath;
    NSLog(@"str = %@",str);
    str = str.stringByExpandingTildeInPath;
    NSLog(@"str = %@",str);

    //stringByResolvingSymlinksInPath Property
    str = @"~/a.txt";
    NSLog(@"str.stringByResolvingSymlinksInPath = %@", str.stringByResolvingSymlinksInPath);

    //stringByStandardizingPath Property
    NSLog(@"str.stringByStandardizingPath = %@", str.stringByStandardizingPath);

    //- stringsByAppendingPaths:
    arr = @[@"a", @"b", @"c", @"d"];
    arr = [str stringsByAppendingPaths:arr];
    NSLog(@"arr = %@", arr);
    //print: arr = (
    //  "~/a.txt/a",
    //  "~/a.txt/b",
    //  "~/a.txt/c",
    //  "~/a.txt/d"
    //  )

    ////////////////////////// Working with URLs //////////////////////////

    //- stringByAddingPercentEscapesUsingEncoding:
    //- stringByReplacingPercentEscapesUsingEncoding:
    str = @"http://218.21.213.10/MobileOA/TIFF/鄂安办发45号关于下达2012年全市安全生产相对控制指标的通知1.jpg";
    str4 = [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"[str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding] = %@", str4);
    str4 = [str4 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"str4 = %@", str4);

    //- stringByAddingPercentEncodingWithAllowedCharacters:
    //- stringByRemovingPercentEncoding
    NSString *unescaped = @"http://www";
    NSString *escapedString = [unescaped stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLHostAllowedCharacterSet]];
    NSLog(@"escapedString: %@", escapedString);
    escapedString = [escapedString stringByRemovingPercentEncoding];
    NSLog(@"escapedString: %@", escapedString);


    ////////////////////////// Linguistic Tagging and Analysis 无语言学积累, 不知道怎么用啊???? 知道的盆友告诉我一下, 非常谢谢! //////////////////////////

    //- enumerateLinguisticTagsInRange:scheme:options:orthography:usingBlock:
    //- linguisticTagsInRange:scheme:options:orthography:tokenRanges:



#pragma mark NSMutableString

    //
    // NSMutableString 是 NSString 的 subClass
    //

    ////////////////////////// Creating and Initializing a Mutable String //////////////////////////

    //+ stringWithCapacity:
    //- initWithCapacity:
    NSMutableString *mStr = [NSMutableString stringWithCapacity:1]; //估计大小
    [mStr appendString:@"aa"];
    NSLog(@"mStr = %@", mStr);


    ////////////////////////// Modifying a String //////////////////////////

    //- appendFormat:
    //- appendString:
    [mStr appendFormat:@"bb"];
    [mStr appendString:@"cc"];
    NSLog(@"mStr = %@", mStr);

    //- deleteCharactersInRange:
    [mStr deleteCharactersInRange:NSMakeRange(mStr.length-2, 2)];
    NSLog(@"mStr = %@", mStr);

    //- insertString:atIndex:
    [mStr insertString:@"__" atIndex:2];
    NSLog(@"mStr = %@", mStr);

    //- replaceCharactersInRange:withString:
    [mStr replaceCharactersInRange:NSMakeRange(2, 2) withString:@"--"];
    NSLog(@"mStr = %@", mStr);

    //- replaceOccurrencesOfString:withString:options:range:
    [mStr replaceOccurrencesOfString:@"-" withString:@"^" options:NSLiteralSearch range:NSMakeRange(0, mStr.length)];
    NSLog(@"mStr = %@", mStr);

    //- setString:
    [mStr setString:@"ccddee"];
    NSLog(@"mStr = %@", mStr);

}


// - initWithFormat:arguments:  // - initWithFormat:locale:arguments:
-(NSString*)vaListTest:(NSString*)args, ...{
    va_list argList;
    va_start(argList, args);
    //NSString *str = [[NSString alloc] initWithFormat:@"%@%@%@" arguments:argList];
    NSString *str = [[NSString alloc] initWithFormat:@"%@%@%@" locale:[NSLocale currentLocale] arguments:argList];
    va_end(argList);
    str = [NSString stringWithFormat:@"%@%@",args,str];
    return str;
}

@end