Function ISMEMBER indexes only the first value and leaves the rest

I'm having a problem with the () function, as it indexes the first value and leaves the duplicate values, the code below is in the figure and the table as well:

x = datetime(Date1,"Format","dd-MMM")

y = datetime(Date2,"Format","dd-MMM")

idx = ismember(x,y)

What is the best solution to this problem?

[Star Strider]

First, be certain that the others are duplicates. That they only display the day and the month does not mean that the other information (year, time, and such) are also the same. Using ismembertol may be more appropriate, after converting the dates to numeric values using datenum.

[Osama Shahin]

@Star Strider The dates are repeated but the time I deleted (I changed the format from 'YYYY-MM-dd hh:mm' to 'YYYY-MM-dd'), originally the date y is a holidays and should extend the whole day, but it's recognized as only 1 hour!

[Star Strider]

That does not change the underlying data. Everything else is still there, since the 'Format' name-value pair only changes the display.

.

Answer 1

[Bruno Luong]

ismember returns in the first argument the logical array, not the index. If you want the firs index (idx will be empty if there is no x in y)

idx = find(ismember(x,y),1,'first')

PS: your screen shot shows xx and yy not x and y.

[Osama Shahin]

I want the full Logical index with duplicate values..

In the comment above, it turns out that the problem is from the date, I want to extend the date for the whole day (24hours) instead pf only the start hour of the day..

[Bruno Luong]

A datetime is a time stamp; it does not have length ("whole day").

Date1 = ["01-Jan 11:22:33", "01-Jan 2:33:44" "02-Oct"];
Date2 = ["01-Jan 15:00:00", "02-Jan 2:33:44"];
x = string(datestr(datenum(Date1),"dd-mmm"))

x = 3×1 string array
    "01-Jan"
    "01-Jan"
    "02-Oct"

y = string(datestr(datenum(Date2),"dd-mmm"))

y = 2×1 string array
    "01-Jan"
    "02-Jan"

ismember(x,y)

ans = 3×1 logical array
   1
   1
   0

[Sean de Wolski]

I want to extend the date for the whole day (24hours) instead pf only the start hour of the day..

In that case, you should dateshift the timestamp to the start or end of the day so that you can then aggregate by day.