NSDateFormatter - objcmemo @ ウィキ

- (NSString *)changeDateFormat8To10:(NSString *)strDate
{
    NSString *str = nil;
    
    NSDateFormatter *beforeFmt = [[NSDateFormatter alloc] init];
    [beforeFmt setDateFormat:@"yy/MM/dd"];

    NSDate *date = [beforeFmt dateFromString:strDate];
    
    NSDateFormatter *afterFmt = [[NSDateFormatter alloc] init];
    [afterFmt setDateFormat:@"yyyy/MM/dd"];
    
    str = [afterFmt stringFromDate:date];
    
    return str;
}



- (NSString *)changeDateFormat10To8:(NSString *)strDate
{
    NSString *str = nil;
    
    NSDateFormatter *beforeFmt = [[NSDateFormatter alloc] init];
    [beforeFmt setDateFormat:@"yyyy/MM/dd"];
    
    NSDate *date = [beforeFmt dateFromString:strDate];
    
    NSDateFormatter *afterFmt = [[NSDateFormatter alloc] init];
    [afterFmt setDateFormat:@"yy/MM/dd"];
    
    str = [afterFmt stringFromDate:date];
    
    return str;
}