如何检查两个字符串是否相同

Question

H guys

silly question but one that is confusing me

print test
print test == "None"

in the terminal this prints out

None
False

as you can see test is None, but the check to see if they are the same comes back false

why is this ?

Answer 1

Try this:

print test
print test == "None"
print test == None
print type(test)

Answer 2

I don't think that you assigned the string "None" to test . It's likely that test is a NoneType so you should test it like this:

print test is None

The result is the same as test == None but the PEP8 says that you should use the keyword is instead of == to test for equality of singleton objects, like None .

Answer 3

In python then None is a data type, so where you can have a number, or a string, you can also have None.

In your case, to check if it's None just remove the quotes:

print test == None

But you got the principle for testing if two strings are the same right:

test = "Hello"
print test
print test == "Hello"

Gives:

Hello
True

Answer 4

It is because None is not a string, it is of type NoneType . Compare it to other languages 'null'. The string with value "None" is not the same as None .

Perhaps the documentation can help you more.