#pragma mark - 创建字符串

- (void)CreatString

{

    // <1> 创建字符串

    NSString *strS = @"This is a String!";

    // <2> 创建空字符串,给予赋值

    NSString *strK = [[NSString alloc] init];

    strK = @"This is a String!";

    NSLog(@"strS:%@, strK%@",strS,strK);

    // <3> 使用变量初始化字符串

    NSString *name = @"aofe";

    NSString *strN = [NSString stringWithFormat:@"My name is %@",name];

    NSLog(@"strN:%@",strN);

}

#pragma mark - 判断是否包含某字符串

- (void)IsContainsString

{

    NSString *str1 = @"NSStringInformation.txt";

    // <1> 检查字符串是否以另一个字符串开头

    [str1 hasPrefix:@"NSString"] == ? NSLog(@"YES") :NSLog(@"NO");

    // <2> 检查字符串是否以另一个字符串结尾

    [str1 hasSuffix:@".txt"] == ? NSLog(@"YES") :NSLog(@"NO");

    // <3> 检查字符串是否包含其他字符串

    [str1 rangeOfString:@"Information"].length >  ? NSLog(@"YES") :NSLog(@"NO");

    // <4> 检查字符串是否包含其他字符串

    [str1 containsString:@"abc"]?NSLog(@"YES"):NSLog(@"NO");

}

#pragma mark - 读写字符串

-(void)WriteAndReadString

{

    // 文件路径

    NSString *path = @"wenJianQuanLuJing";

    // <1> 从文件读取字符串

    NSString *strW = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];

    // <2> 将字符串写入到文件

    [strW writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:NULL];

}

#pragma mark - 比较两个字符串

-(void)ComparerTwoString

{

    NSString *str1 = @"This is String1";

    NSString *str2 = @"THIS is String2";

    // 比较两个字符串是否相等

    BOOL result1 = [str1 isEqualToString:str2];

    // 比较两个字符串(comparer方法返回三种值:NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending)

    NSComparisonResult result2 = [str1 compare:str2];

    // 不考虑大小比较字符串

    NSComparisonResult result3 = [str1 caseInsensitiveCompare:str2];

    NSLog(@"result1:%d,result2:%ld,result3:%ld",result1,(long)result2,(long)result3);

}

#pragma mark - 改变字符串的大小写

-(void)ChangeStringCase

{

    NSString *str1 = @"this is string1";

    NSString *str2 = @"THIS IS STRING2";

    // 全部大写

    [str1 uppercaseString];

    // 全部小写

    [str2 lowercaseString];

    // 首字母大写

    [str1 capitalizedString];

}

#pragma mark - 在字符串中搜索子串

-(void)SearchString

{

    NSString *str1 = @"This is String1";

    NSString *str2 = @"is";

    NSRange range = [str1 rangeOfString:str2];

    NSLog(@"location:%lu,length:%lu",(unsigned long)range.location,(unsigned long)

          range.length);

}

#pragma mark - 替换字符串

-(void)ReplaceString

{

    NSString *strL = @"hello china";

    NSString *strN = [strL stringByReplacingOccurrencesOfString:@"china" withString:@"beijing"];

    NSLog(@"strL:%@,strN:%@",strL,strN);

}

#pragma mark - 分隔字符串成数组

-(void)ComponentsString

{

    NSString *str = @"a b c d e";

    // 以空格分隔字符串成数组

    NSArray *arr = [str componentsSeparatedByString:@" "];

    NSLog(@"arr:%@,arr.count:%lu",arr,(unsigned long)arr.count);

}

#pragma mark - 数组拼接成字符串

-(void)ArrayToString

{

    NSArray *array = [NSArray arrayWithObjects:@"this",@"is",@"String", nil];

    // 用空格隔开数组中的元素

    NSString *str = [array componentsJoinedByString:@" "];

    NSLog(@"str:%@",str);

}

#pragma mark - 从字符串中抽取出新的字符串

-(void)DrawNewString

{

    NSString *str = @"This is String";

    // 从字符串的开头一直截取到指定位置,但不包括该位置的字符.

    NSString *str1 = [str substringToIndex:];

    // 从指定位置开始(包括自定位置的字符串)一直到最后

    NSString *str2 = [str substringFromIndex:];

    // 按照所给定的位置和长度,任意的从字符串中截取新的字符串

    NSString *str3 = [str substringWithRange:NSMakeRange(, )];

    NSLog(@"str1:%@,str2:%@,str3:%@",str1,str2,str3);

}

- (void)NSMutableStringOperation

{

    // 给字符串分配容量

    NSMutableString *strM = [NSMutableString stringWithCapacity:];

    NSLog(@"strM:%@",strM);

    // 在已有的字符串后面添加字符串

    NSMutableString *strM1 = [[NSMutableString alloc] initWithString:@"This is a"];

    NSLog(@"strM1:%@",strM1);

    [strM1 appendString:@"NSMutableString"];

    NSLog(@"strM1:%@",strM1);

    // 在已有字符串中按照所给出的范围和长度删除字符

    [strM1 deleteCharactersInRange:NSMakeRange(, )];

    NSLog(@"strM1:%@",strM1);

    // 在字符串指定位置插入字符串

    [strM1 insertString:@"Hello" atIndex:];

    NSLog(@"strM1:%@",strM1);

    // 将已有字符串替换成其他字符串

    [strM1 setString:@"Hello World"];

    NSLog(@"strM1:%@",strM1);

    // 按照所给出的范围,用新字符串替换原来的字符串

    [strM1 replaceCharactersInRange:NSMakeRange(, ) withString:@"Hi"];

    NSLog(@"strM1:%@",strM1);

}

- (void)NSDateOperation

{

    // 得到当前日期

    NSDate *date1 = [NSDate date];

    NSLog(@"date:%@",date1);

    NSDate *date2 = [NSDate dateWithTimeIntervalSinceNow:];

    // 得到当前时间：coreFoundation框架方法

    double currentTime =CFAbsoluteTimeGetCurrent();

    // 比较日期:

    // <1> 比较日期是否相同

    BOOL result =[date1 isEqualToDate:date2];

    // <2> 比较日期 返回时间较早的日期

    NSDate *dateE = [date1 earlierDate:date2];

    // <3> 比较日期 返回时间较晚的日期

    NSDate *dateL = [date1 laterDate:date2];

    NSLog(@"result:%d, dateE:%@, dateL:%@",result,dateE,dateL);

    // 设置日期的格式

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

    // 设置几种默认的显示效果

    [formatter setTimeStyle:NSDateFormatterMediumStyle];

    //自定义日期显示效果,H大写为24小时计时

    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

    NSString *time = [formatter stringFromDate:date1];

    NSLog(@"%@",time);

}