问题
I have data taken at different times on different days, for example:
dateTimeRead(YYYY-MM-DD HH-mm-ss) rain_value(mm) air_pressure(hPa)
1/2/2015 0:00 0 941.5675
1/2/2015 0:15 0 941.4625
1/2/2015 0:30 0 941.3
1/2/2015 0:45 0 941.2725
1/2/2015 1:00 0.2 941.12
1/2/2015 1:15 0 940.8625
1/2/2015 1:30 0 940.7575
1/2/2015 1:45 0 940.6075
1/2/2015 2:00 0 940.545
1/2/2015 2:15 0 940.27
1/2/2015 2:30 0 940.2125
1/2/2015 16:15 0 940.625
1/2/2015 16:30 0 940.69
1/2/2015 16:45 0 940.6175
1/2/2015 17:00 0 940.635
1/2/2015 19:00 0 941.9975
1/2/2015 20:45 0 942.7925
1/2/2015 21:00 0 942.745
1/2/2015 21:15 0 942.6325
1/2/2015 21:30 0 942.735
1/2/2015 21:45 0 942.765
1/2/2015 22:00 0 7/30/1902
1/3/2015 2:30 0 941.1275
1/3/2015 2:45 0 941.125
1/3/2015 3:00 0 940.955
1/3/2015 3:15 0 941.035
There are dates with missing time stamps.
From these readings how may I extract the maximum values by day for rain_value(mm)?
回答1:
There is a fairly standard array formula style to provide a pseudo-MAXIF function but I prefer to use INDEX and enter it as a standard formula.
With the date to be determined in F3, the formula in G3 is,
=MAX(INDEX(($A$2:$A$999>=$F3)*($A$2:$A$999<(F3+1))*$B$2:$B$999, , ))
A CSE array formula for the same thing would be something like,
=MAX(IF($A$2:$A$999>=$F3, IF($A$2:$A$999<$F3+1, $B$2:$B$900)))
Array formulas need to be finalized with Ctrl+Shift+Enter↵.
回答2:
An array formula may not be suitable for your particular requirement since it seems you may have very many readings. Instead I would suggest a PivotTable, with the date/Time entries parsed (Text to Columns, Fixed width) and date for ROWS, Max of rain_value(mm) for VALUES.
来源：https://stackoverflow.com/questions/29095154/maximum-values-per-day-from-data-with-different-dates