boolean
What’s the difference between Array{Bool} and BitArray in Julia and how are they related?
An Array{Bool} stores each true/false value as a Bool, which is represented internally as a UInt8. So if your array has N elements, it will take N bytes to store it. A BitArray stores each true/false value as a single bit, with (conceptually) 8 of them packed into a single UInt8. Consequently, it takes only … Read more
Are booleans valid JSON
The validator you link to validates the JSON string existing of a mere true as invalid according to RFC 4627, which dictates that the root of a JSON string is to be an array or object: A JSON text is a serialized object or array. JSON-text = object / array An unwrapped value such as … Read more
Does == check for full equality in Booleans? – Java
Does == check for full equality in Booleans? – Java It depends on whether you’re talking about Booleans (the object wrapper, note the capital B) or booleans (the primitive, note the lower case b). If you’re talking about Booleans (the object wrapper), as with all objects, == checks for identity, not equivalence. If you’re talking … Read more
How to count the number of occurrences of `None` in a list?
Just use sum checking if each object is not None which will be True or False so 1 or 0. lst = [‘hey’,’what’,0,False,None,14] print(sum(x is not None for x in lst)) Or using filter with python2: print(len(filter(lambda x: x is not None, lst))) # py3 -> tuple(filter(lambda x: x is not None, lst)) With python3 … Read more
How to convert true false values in dataframe as 1 for true and 0 for false
First, if you have the strings ‘TRUE’ and ‘FALSE’, you can convert those to boolean True and False values like this: df[‘COL2’] == ‘TRUE’ That gives you a bool column. You can use astype to convert to int (because bool is an integral type, where True means 1 and False means 0, which is exactly … Read more
RSpec: How to test for a boolean return type?
expect(variable).to be_in([true, false])
Setting entire bool[] to false [duplicate]
default(bool) is false, just create the array and each element will be false. bool[] switches = new bool[20];
Python’s in (__contains__) operator returns a bool whose value is neither True nor False
You are running into comparison operator chaining; 1 in () == False does not mean (1 in ()) == False. Rather, comparisons are chained and the expression really means: (1 in ()) and (() == False) Because (1 in ()) is already false, the second half of the chained expression is ignored altogether (since False … Read more
form submit checkbox sets value to “on” rather than “true”
A checked checkbox simply sends its value attribute. An unchecked checkbox doesn’t send itself in the form. Therefore, a simple test if the checkbox’s name attribute was posted can determine if it was checked or not.