關(guān)于字符串的一些常用操作

// 創(chuàng)建字符串
- (void)CreatString
    {
        // <1> 創(chuàng)建字符創(chuàng)
        NSString *strS = @"This is a String!";
        
        // <2> 創(chuàng)建空字符串,給予賦值
        NSString *strK = [[NSString alloc] init];
        
        strK = @"This is a String!";
        
        NSLog(@"strS:%@, strK%@",strS,strK);
        
        // <3> 使用變量初始化字符串
        NSString *name = @"aofe";
        
        NSString *strN = [NSString stringWithFormat:@"My name is %@",name];
        
        NSLog(@"strN:%@",strN);
    }
    
    // 判斷是否包含某字符串
    - (void)IsContainsString
        {
            NSString *str1 = @"NSStringInformation.txt";
            
            // <1> 檢查字符串是否以另一個(gè)字符串開(kāi)頭
            [str1 hasPrefix:@"NSString"] == 1? NSLog(@"YES") :NSLog(@"NO");
            
            // <2> 檢查字符串是否以另一個(gè)字符串結(jié)尾
            [str1 hasSuffix:@".txt"] == 1? NSLog(@"YES") :NSLog(@"NO");
            
            // <3> 檢查字符串是否包含其他字符串
            [str1 rangeOfString:@"Information"].length > 0 ? NSLog(@"YES") :NSLog(@"NO");
            
}

// 讀寫(xiě)字符串
-(void)WriteAndReadString
    {
        // 文件路徑
        NSString *path = @"wenJianQuanLuJing";
        
        // <1> 從文件讀取字符串
        NSString *strW = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:NULL];
        
        // <2> 將字符串寫(xiě)入到文件
        [strW writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:NULL];
}

// 比較兩個(gè)字符串
-(void)ComparerTwoString
    {
        NSString *str1 = @"This is String1";
        
        NSString *str2 = @"THIS is String2";
        
        // 比較兩個(gè)字符串是否相等
        BOOL result1 = [str1 isEqualToString:str2];
        
        // 比較兩個(gè)字符串(comparer方法返回三種值:NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending)
        
        NSComparisonResult result2 = [str1 compare:str2];
        
        // 不考慮大小比較字符串
        NSComparisonResult result3 = [str1 caseInsensitiveCompare:str2];
        
        NSLog(@"result1:%d,result2:%ld,result3:%ld",result1,(long)result2,(long)result3);
        
}

// 改變字符串的大小寫(xiě)
-(void)ChangeStringCase
    {
        NSString *str1 = @"this is string1";
        NSString *str2 = @"THIS IS STRING2";
        
        // 全部大寫(xiě)
        [str1 uppercaseString];
        
        // 全部小寫(xiě)
        [str2 lowercaseString];
        
        // 首字母大寫(xiě)
        [str1 capitalizedString];
}

// 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);
        
}

// 替換字符串
-(void)ReplaceString
    {
        NSString *strL = @"hello china";
        
        NSString *strN = [strL stringByReplacingOccurrencesOfString:@"china" withString:@"beijing"];
        
        NSLog(@"strL:%@,strN:%@",strL,strN);
}

// 分隔字符串成數(shù)組
-(void)ComponentsString
    {
        NSString *str = @"a b c d e";
        // 以空格分隔字符串成數(shù)組
        NSArray *arr = [str componentsSeparatedByString:@" "];
        
        NSLog(@"arr:%@,arr.count:%lu",arr,(unsigned long)arr.count);
        
}

// 數(shù)組拼接成字符串
-(void)ArrayToString
    {
        NSArray *array = [NSArray arrayWithObjects:@"this",@"is",@"String", nil];
        // 用空格隔開(kāi)數(shù)組中的元素
        NSString *str = [array componentsJoinedByString:@" "];
        
        NSLog(@"str:%@",str);
}

// 從字符串中抽取出新的字符串
-(void)DrawNewString
    {
        NSString *str = @"This is String";
        // 從字符串的開(kāi)頭一直截取到指定位置,但不包括該位置的字符.
        NSString *str1 = [str substringToIndex:5];
        
        // 從指定位置開(kāi)始(包括自定位置的字符串)一直到最后
        NSString *str2 = [str substringFromIndex:5];
        
        // 按照所給定的位置和長(zhǎng)度,任意的從字符串中截取新的字符串
        NSString *str3 = [str substringWithRange:NSMakeRange(4, 5)];
        
        NSLog(@"str1:%@,str2:%@,str3:%@",str1,str2,str3);
    }
    
    // 可變字符串的操作
    - (void)NSMutableStringOperation
        {
            // 給字符串分配容量
            NSMutableString *strM = [NSMutableString stringWithCapacity:100];
            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給出的范圍和長(zhǎng)度刪除字符
            [strM1 deleteCharactersInRange:NSMakeRange(0, 5)];
            NSLog(@"strM1:%@",strM1);
            
            // 在字符串指定位置插入字符串
            [strM1 insertString:@"Hello" atIndex:0];
            NSLog(@"strM1:%@",strM1);
            
            // 將已有字符串替換成其他字符串
            [strM1 setString:@"Hello World"];
            NSLog(@"strM1:%@",strM1);
            
            // 按照所給出的范圍,用新字符串替換原來(lái)的字符串
            [strM1 replaceCharactersInRange:NSMakeRange(0, 5) withString:@"Hi"];
            NSLog(@"strM1:%@",strM1);
        }
        
        // 時(shí)間操作
        - (void)NSDateOperation
            {
                // 得到當(dāng)前日期
                NSDate *date1 = [NSDate date];
                NSLog(@"date:%@",date1);
                
                NSDate *date2 = [NSDate dateWithTimeIntervalSinceNow:3];
                
                // 比較日期:
                
                // <1> 比較日期是否相同
                BOOL result =[date1 isEqualToDate:date2];
                
                // <2> 比較日期 返回時(shí)間較早的日期
                NSDate *dateE = [date1 earlierDate:date2];
                
                // <3> 比較日期 返回時(shí)間較晚的日期
                NSDate *dateL = [date1 laterDate:date2];
                
                NSLog(@"result:%d, dateE:%@, dateL:%@",result,dateE,dateL);
                
                // 設(shè)置日期的格式
                NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
                
                // 設(shè)置幾種默認(rèn)的顯示效果
                [formatter setTimeStyle:NSDateFormatterMediumStyle];
                
                //自定義日期顯示效果
                [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
                
                NSString *time = [formatter stringFromDate:date1];
                
                NSLog(@"%@",time);
                
}