Thanks for the response.
I must have spent hours looking on-line for a method to treat datetime
variables yet not one site mentioned the "pickle" module you indicatged. I
did, however solve my problem. It may be a kluge but it seems to work.
I learned that I cannot use print() to display the value of datetime but
once I saved it to a file, I could see it. If I used "d3 = d2.isoformat" it
could be sent to a file with a write statement. Apparently, it gives a
write/read format and places a T between the date and time as a separator.
In trying to read it back into the program and work the calculation, I had
to replace the T with a space and some formatting. It all worked.
#===============================================
LBD = "LBD"
d2 = datetime.now()
d2i = d2.isoformat()
with open("TimeDate.txt", 'r') as infile:
for BottleInfo in infile: # loop to find each line in the file for that
dose
BottleInfo = BottleInfo.strip()
if ((BottleInfo[0:3]== "LBD")):
BottleData = BottleInfo[0:43].strip()
BottleDataA = BottleData[4:14].strip()
BottleDataB = BottleData[16:30].strip()
BottleDataC = BottleDataA + " " + BottleDataB
print("BottleDataC = <" + BottleDataC + ">")
# I guess I could have searched for the "T" and replaced it.
print()
d1 = BottleDataC
import datetime
dto = datetime.datetime.strptime(d1, '%Y-%m-%d %H:%M:%S.%f')
dti = dto.isoformat()
HoursDiff = int((d2-dto).total_seconds()/3600)
print("HoursDiff = " + str(HoursDiff))
print()
TimeDateInfo=open("TimeDate.txt", "a")
TimeDateInfo.write("{0:>5} {1:>25} {2:>5}\n".format (LBD, d2i, HoursDiff))
TimeDateInfo.close()
# ===========================================
Granted, there may be other ways to do this but I actually enjoy the
exploration...
Still, I would like to see other methods.
Steve
-----Original Message-----
From: Dieter Maurer <die...@handshake.de>
Sent: Sunday, October 11, 2020 12:48 PM
To: Steve <Gronicus@SGA.Ninja>
Subject: Re: Problem saving datetime to file and reading it back for a
calculation
Steve wrote at 2020-10-10 18:17 -0400:
>I would like to use the line:
>HoursDiff = int((d2-d1).total_seconds()/3600) to determine the
>difference in hours between two timedate entries.
>
>The variable d2 is from datetime.now()
>and d1 is read from a text file.
>
>I can save d2 to the file only if I convert it to string and, at a later
>date, it gets read back in as d1 as string. The variable d1 as string
will
>not work in the HoursDiff statement.
Python's "pickle" module provides support for storing (most) objects to
files and read them back.
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