'yyyy-mm-dd hh:mm a' inputFormat in 'datetime' function

Hi:

I'm trying to convert a string to datetime, below are the result of two command:

datetime('2022-02-22 9:30 am','InputFormat','yyyy-mm-dd hh:mm a','TimeZone', 'America/New_York')
ans = 22-Jan-2022 09:30:00

datetime('2022-02-22 9:30 am','TimeZone', 'America/New_York')
ans = 22-Feb-2022 09:30:00

the 2nd returns the result I want, but I'm interest to know why the 1st is wrong.

Thanks!

Yu

Answer 1

[the cyclist]

The warning message you got from the first line tells you exactly what the problem is:

datetime('2022-02-22 9:30 am','InputFormat','yyyy-mm-dd hh:mm a','TimeZone', 'America/New_York')

Warning: The format 'yyyy-mm-dd hh:mm a' contains a field for minute (m) in what appears to be a date portion. You might have intended to use the symbol for month (M) rather than for minute (m). See the datetime.Format property for a complete description of the identifiers used in datetime formats.

ans = datetime
   22-Jan-2022 09:30:00

You needed

datetime('2022-02-22 9:30 am','InputFormat','yyyy-MM-dd hh:mm a','TimeZone', 'America/New_York')

ans = datetime
   22-Feb-2022 09:30:00

[Yu Li]

thanks... but unfortunately I do not see any warning message while executing the code, may I know your Matlab version? I'm using 2021b.

[the cyclist]

I'm using the same version, and also that is what is running here on the Answers forum.

It's possible you have turned off the display of this warning. What does

[msg,warnID] = lastwarn()

give after running the above code?

[Yu Li]

[msg,warnID] = lastwarn () 

msg =

'The format 'yyyy-mm-dd hh:mm a' contains a field for minute (m) in what appears to be a date portion. You might have intended to use the symbol for month (M) rather than for minute (m). See the datetime.Format property for a complete description of the identifiers used in datetime formats.'

warnID =

'MATLAB:datetime:FormatConflict_mM'

it just did not appear automatically.

[the cyclist]

Warnings are on by default. In your instance of MATLAB, this warning -- or possibly all warnings -- must have been turned off. I would recommended looking at this documentation, to understand how warnings get suppressed and restored.

[Yu Li]

will do, thank you!