iOS:比较两个小于或等于的 NSDates [英] iOS: Compare two less or equal NSDates

问题描述

我想比较两个日期并在一个日期小于或等于另一个时执行某些操作，我尝试这样做:

I want to compare two dates and do something when one is less or equal than the other, I tried to do it this way:

if ([self.system.systemInbetriebnahme compare:date] == NSOrderedDescending)
        return nil;

但是这消除了它们相等的情况有没有办法将日期与 >= 进行比较?

But this removes the case when they are both equal is there a way to compare dates with >= ?

谢谢

更多细节:我有一个取自一个二维数组的日期，我有一个存储在核心数据中的日期(通过日期选择器)，我通过一个循环来比较两个日期规则是:数组中的日期必须大于或等于存储在数据库中的输入日期.

More details: I have a date taken from a double dimension array, and i have a date stored in core data(through date picker), and i go through a loop to compare the two dates with the rule that: Date in array must be greater or equal than input date stored in database.

最新

• 我导入了一个 csv 文件，在解析和格式化后给了我两行(一行用于数值，另一行用于日期).在这里，我对日期感兴趣.

• I import a csv file which after parsing and formatting gives me two rows(one for number value and one for dates). Here I am interested in dates.

我将所有这些存储在一个数组中，并在此函数中检查数据的一致性后保存:

I store all these in an array and save after checking consistency of the data in this function:

for (NSArray * row in array) {


 // Handle import if there are at least two rows


if (row.count > 1) {

            dispatch_sync(dispatch_get_main_queue(), ^{
                // Try to import value,date formatted row
                double value = [row[0] doubleValue];
                NSDate * date = [dateFormatter dateFromString:row[1]];
               //else {

                    // Try to import date,value row

                    if (date && value != 0.0) {
                        [self addReading:value forDate:date];
                    }

在这里我调用函数 addreading 来检查某些规则的错误，如果一切正常，那么我保存托管对象上下文.

In here i call the function addreading to check for errors for some rules and if everything is okey then i save the managedObject Context.

 if ([installationdatum compare:date] != NSOrderedAscending)
               { 
               UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil
                 message:@"installation date is bigger than data"
                                                                  delegate: nil
                                                         cancelButtonTitle:@"OK"
                                                         otherButtonTitles:nil] 

                    [alert show];
                   return nil;



               } else
               {  //Do nothing

               }

我的一个规则是获取数组中的第一行元素，并将其日期与已存储在数据库中的输入进行比较，该输入是 self.system.systemInbetriebnahme

毕竟，我在 tableview 中列出了所有结果数组，尽管当它等于 self.system.systemInbetriebnahme 时，永远不会显示匹配 NSOrderedSame 的值

After all this I list all the resulting array in a tableview, though value matching NSOrderedSame is never shown when it is equal to self.system.systemInbetriebnahme

推荐答案

只需检查不升序即可.

if ([self.system.systemInbetriebnahme compare:date] != NSOrderedAscending)
        return nil;

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