dynamic

问题 I am trying to create a method in python insert records into a table passing in a list of column names, and an associated list of records. I was able to set it up where the column names populated dynamically via a for loop, but I can't figure out how to do the same thing with values because the psycopg2.executemany function relies on having %s's as placeholders. Is it possible to have the number of %s's in the string populate dynamically via a loop? Is there another way to do this? def load

问题 Is there a way to dynamically cast at runtime like the following pseudo code: foreach (DataRow row in table.Rows) { foreach (DataColumn col in table.Columns) { if (row[col] != DBNull.Value) { Type type = col.DataType; type cellContent = (type)row[col]; //Pseudo-Code } } } I´ve been searching the web and not found anything. There´s object obj = Activator.CreateInstance(type); , but then I´m still stuck with an object and can´t use specific type methods with it. Also I need a cast of an

问题 Is there a way to dynamically cast at runtime like the following pseudo code: foreach (DataRow row in table.Rows) { foreach (DataColumn col in table.Columns) { if (row[col] != DBNull.Value) { Type type = col.DataType; type cellContent = (type)row[col]; //Pseudo-Code } } } I´ve been searching the web and not found anything. There´s object obj = Activator.CreateInstance(type); , but then I´m still stuck with an object and can´t use specific type methods with it. Also I need a cast of an

问题 I have a common construct in an unmanaged Win32 C++ DLL: // FirstElemPtrContainer.h #include "stdafx.h" typedef unsigned char elem_type; // a byte typedef struct FirstElemPtrContainer { unsigned char num_elems; void *allocd_ary; } FirstElemPtrContainer; The void* in the struct is meant to contain a pointer to the first element of an allocated byte array. The DLL that uses this definition then exports functions to allocate, populate, and deallocate the struct: // The exported allocator

问题 I have a common construct in an unmanaged Win32 C++ DLL: // FirstElemPtrContainer.h #include "stdafx.h" typedef unsigned char elem_type; // a byte typedef struct FirstElemPtrContainer { unsigned char num_elems; void *allocd_ary; } FirstElemPtrContainer; The void* in the struct is meant to contain a pointer to the first element of an allocated byte array. The DLL that uses this definition then exports functions to allocate, populate, and deallocate the struct: // The exported allocator

问题 I have a common construct in an unmanaged Win32 C++ DLL: // FirstElemPtrContainer.h #include "stdafx.h" typedef unsigned char elem_type; // a byte typedef struct FirstElemPtrContainer { unsigned char num_elems; void *allocd_ary; } FirstElemPtrContainer; The void* in the struct is meant to contain a pointer to the first element of an allocated byte array. The DLL that uses this definition then exports functions to allocate, populate, and deallocate the struct: // The exported allocator

问题 So I was making a console application using Python 3.7; that heavily depends on input (wowz). The application's function is to "swap" between two integer variables' values. And that is not where the problem is at, the problem is when I try to validate the user's input by checking the data-type for the input using a couple "if statements", and no matter what the user inputs using the " input() " function; the input's data-type will always be defined as "" I just want this little piece of ART

问题 So I was making a console application using Python 3.7; that heavily depends on input (wowz). The application's function is to "swap" between two integer variables' values. And that is not where the problem is at, the problem is when I try to validate the user's input by checking the data-type for the input using a couple "if statements", and no matter what the user inputs using the " input() " function; the input's data-type will always be defined as "" I just want this little piece of ART

问题 I would like to call an object method dynamically. The variable "MethodWanted" contains the method I want to execute, the variable "ObjectToApply" contains the object. My code so far is: MethodWanted=".children()" print eval(str(ObjectToApply)+MethodWanted) But I get the following error: exception executing script File "<string>", line 1 <pos 164243664 childIndex: 6 lvl: 5>.children() ^ SyntaxError: invalid syntax I also tried without str() wrapping the object, but then I get a "cant use +

问题 I would like to call an object method dynamically. The variable "MethodWanted" contains the method I want to execute, the variable "ObjectToApply" contains the object. My code so far is: MethodWanted=".children()" print eval(str(ObjectToApply)+MethodWanted) But I get the following error: exception executing script File "<string>", line 1 <pos 164243664 childIndex: 6 lvl: 5>.children() ^ SyntaxError: invalid syntax I also tried without str() wrapping the object, but then I get a "cant use +