Integer and String comparison conflict in VBScript

Question

The below VBScript code while trying to run in HP-UFT confused me because the first statement prints True instead of False (which does not seem logical), while the second one prints False (which seems logical)

Code:

print 40 = "40"

a = 40
b = "40"
print a = b

Output:

True
False

Answer 1

It's perfectly logical (cough), there is only one data type in VBScript and that is Variant. However VBScript can handle many different sub types of the Variant data type.

When you compare

40 = "40"

VBScript is implicitly converting the String sub type to an Integer sub type and comparing the result which is the same as performing the following explicit conversion;

40 = CInt("40")

If you already have your variants defined however VBScript only attempts to implicitly convert them if the execution context fits (when it fits is a bit hazy and in some cases a straight up bug - See Ref).

To avoid this use explicit conversions when necessary.

a = CInt(b)

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Useful Links

• A: VBScript implicit conversion in IF statement different from variable to literals?
• MSDN Blog - Typing Hard Can Trip You Up (Eric Lippert)