boolean

问题 I am trying to import a csv into a pandas dataframe. I have boolean variables denoted with 1's and 0's, where missing values are identified with a -9. When I try to specify the dtype as boolean, I get a host of different errors, depending on what I try. Sample data: test.csv var1, var2 0, 0 0, 1 1, 3 -9, 0 0, 2 1, 7 I try to specify the dtype as I import: dtype_dict = {'var1':'bool','var2':'int'} nan_dict = {'var1':[-9]} foo = pd.read_csv('test.csv',dtype=dtype_dict, na_values=nan_dict) I get

问题 Here is a JSON string that contains a list of objects with each having another list embedded. [ { "name": "Alice", "hobbies": [ "volleyball", "shopping", "movies" ] }, { "name": "Bob", "hobbies": [ "fishing", "movies" ] } ] Using pandas.read_json() this turns into a DataFrame like this: name hobbies -------------------------------------- 1 Alice [volleyball, shopping, movies] 2 Bob [fishing, movies] However, I would like to flatten the lists into Boolean columns like this: name volleyball

问题 Here is a JSON string that contains a list of objects with each having another list embedded. [ { "name": "Alice", "hobbies": [ "volleyball", "shopping", "movies" ] }, { "name": "Bob", "hobbies": [ "fishing", "movies" ] } ] Using pandas.read_json() this turns into a DataFrame like this: name hobbies -------------------------------------- 1 Alice [volleyball, shopping, movies] 2 Bob [fishing, movies] However, I would like to flatten the lists into Boolean columns like this: name volleyball

问题 I sent a reference to a bool object, and I modified it within a method. After the method finished it's execution, the value of the bool outside the method was unchanged. This leads me to believe that Python's bools are passed by value. Is that true? What other Python types behave that way? 回答1: Python variables are not "references" in the C++ sense. Rather, they are simply local names bound to an object at some arbitrary location in memory. If that object is itself mutable, changes to it will

问题 I have the following code in python: def update(request, id): success = 0 try: product = Mattress.objects.get(id=id) success = 1 except Mattress.DoesNotExist: pass if success == 1: return render_to_response("success.html") else: return render_to_response('failure.html') Is this code a valid way to check the "success" boolean. If the code passes through the try statement, will "success" be changed to 1 or is it remaining at 0? 回答1: Answering your question: Are booleans mutable in python? Yes

问题 I have the following code in python: def update(request, id): success = 0 try: product = Mattress.objects.get(id=id) success = 1 except Mattress.DoesNotExist: pass if success == 1: return render_to_response("success.html") else: return render_to_response('failure.html') Is this code a valid way to check the "success" boolean. If the code passes through the try statement, will "success" be changed to 1 or is it remaining at 0? 回答1: Answering your question: Are booleans mutable in python? Yes

问题 I have the following code in python: def update(request, id): success = 0 try: product = Mattress.objects.get(id=id) success = 1 except Mattress.DoesNotExist: pass if success == 1: return render_to_response("success.html") else: return render_to_response('failure.html') Is this code a valid way to check the "success" boolean. If the code passes through the try statement, will "success" be changed to 1 or is it remaining at 0? 回答1: Answering your question: Are booleans mutable in python? Yes

问题 I have the following code in python: def update(request, id): success = 0 try: product = Mattress.objects.get(id=id) success = 1 except Mattress.DoesNotExist: pass if success == 1: return render_to_response("success.html") else: return render_to_response('failure.html') Is this code a valid way to check the "success" boolean. If the code passes through the try statement, will "success" be changed to 1 or is it remaining at 0? 回答1: Answering your question: Are booleans mutable in python? Yes

问题 I have the following code in python: def update(request, id): success = 0 try: product = Mattress.objects.get(id=id) success = 1 except Mattress.DoesNotExist: pass if success == 1: return render_to_response("success.html") else: return render_to_response('failure.html') Is this code a valid way to check the "success" boolean. If the code passes through the try statement, will "success" be changed to 1 or is it remaining at 0? 回答1: Answering your question: Are booleans mutable in python? Yes

问题 This question already has answers here : Boolean literals in PowerShell (3 answers) Closed 1 year ago . When I study PowerShell scripting language, I knew the data type is auto-assignment. If I want to declare a Boolean type variable, how can I do it? Example: $myvariable = "string" or $myvalue = 3.14159 $myboolean ? 回答1: Boolean values (which can be either 1 or 0) are defined in PowerShell using the .Net System.Boolean type (the short from of which is [bool]). For example, the following