how to match with random cell name with varied format

I have a series of cell array

XXXX-20-0266-3.dat
XXXX-10-01-12_03.03.03 AM.dat
XXXX-10-01-12_01.03.03 PM.dat
XXXX-30-0333.dat

I want to match with AM or PM, I try to use regexp function, regexp(cell{2}, [xxxx '-?\w*AM.csv'], it does not work. how I can achieve it since the middle always change its length and content? Please help me. I appreciate for your time and efforts.

Answer 1

[Image Analyst]

Not exactly sure what kind of variable you want to get, but study this snippet:

ca = {'XXXX-20-0266-3.dat';
'XXXX-10-01-12_03.03.03 AM.dat';
'XXXX-10-01-12_01.03.03 PM.dat';
'XXXX-30-0333.dat'}
amIndexes = strfind(ca, 'AM') % amIndexes is a cell
pmIndexes = strfind(ca, 'PM') % pmIndexes is a cell
logicalIndexesAM = ~cellfun(@isempty, amIndexes)
logicalIndexesPM = ~cellfun(@isempty, pmIndexes)
linearIndexesAM = find(logicalIndexesAM)
linearIndexesPM = find(logicalIndexesPM)

In the command window:

ca = 
    'XXXX-20-0266-3.dat'
    'XXXX-10-01-12_03.03.03 AM.dat'
    'XXXX-10-01-12_01.03.03 PM.dat'
    'XXXX-30-0333.dat'
amIndexes = 
    []
    [24]
    []
    []
pmIndexes = 
    []
    []
    [24]
    []
logicalIndexesAM =
     0
     1
     0
     0
logicalIndexesPM =
     0
     0
     1
     0
linearIndexesAM =
     2
linearIndexesPM =
     3

Does that help at all? Can you get whatever you need from that? Or do you need more help?

[Jiali]

Thank you for your time. You give clear explanation for what I describe. I need more help. In my case, all these are name of files. I search to match file name with input array. The input array will be matched with XXXX (e.g. cellnumb1025). Then I need to further find whether XXXX_AM or XXXX_PM to get newest data for same filename. ( I have lots of data, and each sample may be tested more than more times. For same period of time, I already sorted from small to large according to time, but it doesn't work for XXXX_PM or XXXX_AM) Currently, my thought will be compare file name with input array +whatever in middle + AM/PM. But I have trouble to implement it.

[Image Analyst]

I didn't quite follow. But can't you just use strfind() like I did to search for whatever you want?