【IT168 技术】

　　Cocoa中常用的类

　　NSStringNSMutableString

　　赋值NSString *myString = @"some string";

　　NSString *myString = [NSStringstringWithFormat:@"object = %@",someObject];

　　转换NSString *upper = [myStringuppercaseString];

　　intintString = [myStringintValue];

　　去内容NSString *trimmed = [myString string ByTrimmingCharactersInSet: [NSCharacterSet whitespace CharacterSet]];

　　截取字符串NSString *aString = [numberStringsubstringToIndex:3];

　　NSRange range = NSMakeRange(4,3);

　　NSString *aString = [numberStringsubstringWithRange:range];

　　NSArray *arr = [numberString

　　?componentsSeparatedByString:

　　? @" "];

　　替换NSString *aString = [numberStringstringByReplacingOccurrencesOf

　　? String:@"three" withString: @"four"];

　　查找NSRangefoundRange = [numberStringrangeOfString:@"two"];

　　BOOL found = ([numberStringrangeOfString:@"two"].location != ?NSNotFound);

　　文件NSString *fileContents = [NSStringstringWithContentsOfFile: ? @"myfile.txt"];

　　NSURL *url = [NSURL URLWithString:? @"http://google.com"];

　　NSString *pageContents = [NSString?stringWithContentsOfURL:url];

　　Date Times

　　NSDate *myDate = [NSDate date];

　　NSTimeIntervalsecondsPerDay = 24*60*60;

　　NSDate *now = [NSDate date];

　　NSDate *yesterday = [now addTimeInterval:-secondsPerDay];

　　NSDateComponents *comp = [[NSDateCo m ponentsalloc] init];

　　[co m p setMonth:06];

　　[co m p setDay:01];

　　[co m p setYear:2010];

　　NSCalendar *myCal= [[NSCalendaralloc] initWithCalendarIdentifier: NSGregorianCalendar];

　　NSDate *myDate= [myCaldateFromComponents:comp];

　　NSArrayNSMutableArrayDictionary

　　NSString *string1 = @"one";

　　NSString *string2 = @"two";

　　NSString *string3 = @"three";