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ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
I just discovered a logical bug in my code which was causing all sorts of problems. I was inadvertently doing a bitwise AND instead of a logical AND .
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How to get the first element of the List or Set? [duplicate]
I'd like to know if I can get the first element of a list or set. Which method to use?
9 Answers
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How do I check if a column is empty or null in MySQL?
I have a column in a table which might contain null or empty values. How do I check if a column is empty or null in the rows present in a table?
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What is the difference between the | and || or operators?
I have always used || (two pipes) in OR expressions, both in C# and PHP. Occasionally I see a single pipe used: | . What is the difference between those two usages? Are there any caveats when using one over the other or are they interchangeable?
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Check whether a path is valid in Python without creating a file at the path's target
I have a path (including directory and file name).
I need to test if the file-name is a valid, e.g. if the file-system will allow me to create a file with such a name.
The file-name has some unicode characters in it.
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Evaluate empty or null JSTL c tags
How can I validate if a String is null or empty using the c tags of JSTL ?
8 Answers
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IF… OR IF… in a windows batch file
Is there a way to write an IF OR IF conditional statement in a windows batch-file?
14 Answers
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Is there an easy way to check the .NET Framework version?
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Something like this should do it. Just grab the value from the registry
For .NET 1-4:
Framework is the highest installed version, SP is the service pack for that version.
RegistryKey installed_versions = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP");
string[] ve...
When can I use a forward declaration?
I am looking for the definition of when I am allowed to do forward declaration of a class in another class's header file:
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Does Python support short-circuiting?
Does Python support short-circuiting in boolean expressions?
3 Answers
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