Foundation 基础类

NSString * str = @"adf";

NSString * str3 = [NSString stringWithFormat:@"%@,%@",@"a",@"b"];

char * c = "www";
NSString * str4 = [[NSString alloc] initWithCString:c encoding:nil];

NSUInteger length =   [str length];

unichar c = [str2 characterAtIndex:2];//索引值是从 0 开始的

NSString * tmpStr = [str3 substringFromIndex:3];

NSString * tmpStr2 = [str3 substringToIndex:3];

NSString * tmpStr3 = [str3 substringWithRange:rang];

NSRange tmpRange = [str3 rangeOfString:tmpStr4];

if (str == nil || str.length == 0)
        {
            NSLog(@"字符串为空");
        }

BOOL isPerfix = [str2 hasPrefix:@"xww"];

BOOL isSuffix = [str3 hasSuffix:@".txt"];

BOOL isEqual = [pstr5 isEqualToString:pstr3];

NSComparisonResult result = [strTmp1 compare:strTmp2];

NSString * str1 = [NSString stringWithFormat:@"%d",a];

NSString * str3 = [NSString stringWithFormat:@"%.1f",f];

NSString * str4 = [NSString stringWithFormat:@"%.4f",d];

NSString * str5 = [NSString stringWithFormat:@"%c",c];

int i1 = [str6 intValue];

float f1 = [str7 floatValue];

double d1 = [str8 doubleValue];

//7.将字符串中的字母转换成大写
        NSString * str10 = @"china";
        NSString * tmpStr1 = [str10 uppercaseString];
        NSLog(@"tmpStr1 %@ str10 %@",tmpStr1,str10);
        
        //8.将字符中的字母转换成小写
        NSString * str11 = @"CHINA";
        NSString * tmpStr2 = [str11 lowercaseString];
        NSLog(@"tmpStr2 %@",tmpStr2);
        
        //9.将首字母大写
        NSString * str12 = @"china";
        NSString * tmpStr3 = [str12 capitalizedString];
        NSLog(@"tmpStr3  %@",tmpStr3);

NSString * date = [NSString stringWithFormat:@"%d年%d月%d日",year,month,day];

NSString * str2 = [str1 stringByAppendingString:@"itcast.cn"];

NSString * str4 = [str3 stringByReplacingCharactersInRange:range withString:@"itcast."];

NSString * str6 = [str5 stringByReplacingOccurrencesOfString:@"w" withString:@"a"];

BOOL isWriteSuccess = [content writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error];

NSString * str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];

NSMutableString * muStr = [[NSMutableString alloc] initWithCapacity:0];
        
        //是初始化字符串内容
        [muStr setString:@"www"];
        
        NSLog(@"mustr %p",muStr);
        
        //动态的给字符串末尾追加新值
        [muStr appendString:@".cn"];
        
        //在指定的索引位置,插入字符串
        [muStr insertString:@".itcast" atIndex:3];
        
        //删除指定范围的字符串
        //你要删除的长度,一定不能够超出字符串的的长度,导致异常Range or index out of bounds
        NSRange range = {3,7};
//        [muStr deleteCharactersInRange:range];
        
        [muStr replaceCharactersInRange:range withString:@"传智播客"];

//1.创建一个NSRange结构体 表示范围
        NSRange range = {4,5};
        NSRange range2 = NSMakeRange(4, 5);
        NSString * strRange = NSStringFromRange(range);
        NSLog(@"strRange %@",strRange);
        
        //2.NSSize 等同于 CGSize 有两个值组成 weight表示宽度 height高度
        NSSize  size = {21,19};
        NSSize  size2 = NSMakeSize(21, 19);
        NSString *strSize =  NSStringFromSize(size2);
        NSLog(@"strSize %@",strSize);
        
        //3.NSPoint 等同CGPoint 表示一个点的坐标位置
        NSPoint point = {20,40};
        NSPoint point2 = NSMakePoint(20, 40);
        NSString * strPoint = NSStringFromPoint(point);
        NSLog(@"strPoint %@",strPoint);
        
        //4.NSRect
        NSRect rect = {40,60,100,200};
        NSRect rect2 = NSMakeRect(0, 10, 100, 100);
        NSString * strRect = NSStringFromRect(rect);
        NSLog(@"strRect %@",strRect);

#pragma mark 判断数组中是否存在某个对象

BOOL isContain = [array containsObject:p1];