日期时间，字符串比较

Question

我需要将传入的字符串与来自 DS1307 RTC 模块的日期和时间进行比较。如果到达字符串中的特定时间，我将触发一个事件。

我尝试过使用转换为整数，但它不起作用。

String now_int = rtc.now();

错误提示conversion from DateTime to non-scalar type String is requested

如何比较日期时间和字符串？

Answer 1

您可以使用sprintf 和strcmp 的组合来实现您描述的行为，例如类似于this

// date and time from RTC
DateTime now = rtc.now();

// date and time to compare with - this is provided by you
String datetimeCompare = "1970/01/01 00:00:00";

// this buffer must be big enough for your complete datetime (depending on the format)
char datetimeBuffer[20] = "";

// convert current date and time to your specific format
sprintf(datetimeBuffer, "%04d/%02d/%02d %02d:%02d:%02d", now.year(), now.month(), now.day(), now.hour(), now.minute(), now.second());

// perform the comparison
if(strcmp(datetimeBuffer, datetimeCompare.c_str()) == 0)
{
    // datetime strings are the same
}

或者您根据arduino stackexchange 中所述的格式转换您的 rtc.now() DateTime。