Python：日期比较未通过相等性测试

Question

I'm a python beginner. Here is the code that I'm trying to run:

matexp = input("What's the material expiration date (mm/dd/yy): ")
matexpir = datetime.strptime(matexp, "%m/%d/%y")

d1 = datetime.today()

d2 = timedelta(days=30)

d3 = d1 + d2

if matexpir == d3:
    matstat = "CAUTION"
elif matexpir <= d1:
    matstat = "EXPIRED"
else :
    matstat = "Null"

While testing this code, I can get it to print matstat or Status = 'EXPIRED' on a table, but when I try to get it to print 'CAUTION', it doesn't and goes straight to 'Null'. Why is that? How may I fix it? Please help.

Thank you.

Answer 1

In its current form, the test is comparing a date and a datetime , which will obviously never be equal.

To address this, the comparison should be like-for-like. Compare dates , with the time factor removed.

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The fix:

Change this:

matexpir = datetime.strptime(matexp, "%m/%d/%y")

to:

matexpir = datetime.strptime(matexp, "%m/%d/%y").date()

And change this:

d1 = datetime.today()

to:

d1 = datetime.today().date()    

---

Full solution:

from datetime import datetime, timedelta

matexp = input("What's the material expiration date (mm/dd/yy): ")
matexpir = datetime.strptime(matexp, "%m/%d/%y").date()

d1 = datetime.today().date()
d2 = timedelta(days=30)
d3 = d1 + d2

if matexpir == d3:
    matstat = "CAUTION"
elif matexpir <= d1:
    matstat = "EXPIRED"
else:
    matstat = "Null"