function

问题 I want to return a class instance in member function of a class, my code is: class MyClass(object): def __init__(self, *args, **kwargs): [snippet] def func(self, *args, **kwargs): [snippet] return class_instnace_of_MyClass if __name__ == '__main__': obj = MyClass(...) newobj = obj.func(...) # type(newobj) is MyClass I think I can call __init__() in func() , and return a new instance of MyClass, but I don't think it is a Pythonic way to do so. How should I do that? Thank you! 回答1: I feel like

问题 I have some data, stored in Column A and column B. For each row, I would like to get the difference between the values in column A and column B. I.e. cells(1,2) - cells(1,1), so on so forth for the rest of rows. The second step is to determine if the difference on i row was the max of the preceeding nth rows. With helper column, I can do it with formula or with code like this. for i = 1 to LR cells(i,3) = cells(i,2) - cells(i,1) next i for i = 1 to LR if cells(i,3) = .max(range(cells(i-19,3)

问题 The function is big but I have take some code from that function and I have a question that how to find that specific name from text file? I am not sure. for (option = 1; option <= sizeof(listing)/sizeof(char *); ++option) printf("%d. Your %s:\n", option, listing[option-1]); fputs("Select your choice to update: ", stdout); if ((scanf("%d", &option) != 1) || (option < 1) || (option > sizeof(listing)/sizeof(char *))) { puts("invalid choice"); fclose(fr3); return -1; } int one_by_one; printf(

问题 The function is big but I have take some code from that function and I have a question that how to find that specific name from text file? I am not sure. for (option = 1; option <= sizeof(listing)/sizeof(char *); ++option) printf("%d. Your %s:\n", option, listing[option-1]); fputs("Select your choice to update: ", stdout); if ((scanf("%d", &option) != 1) || (option < 1) || (option > sizeof(listing)/sizeof(char *))) { puts("invalid choice"); fclose(fr3); return -1; } int one_by_one; printf(

问题 This is a follow up question for write to output stream and returning value from shell script function. In shell script, echo can be used to return values from functions. But, if those functions want to print some messages. Then, this can be done by redirecting it to error stream. But when the script is used as a autosys job. then messages from logic functions ends up in error stream file triggering alerts. Is there any way, messages from logic function can be written to output stream and not

问题 This is a follow up question for write to output stream and returning value from shell script function. In shell script, echo can be used to return values from functions. But, if those functions want to print some messages. Then, this can be done by redirecting it to error stream. But when the script is used as a autosys job. then messages from logic functions ends up in error stream file triggering alerts. Is there any way, messages from logic function can be written to output stream and not

问题 I created a stored procedure in PostgreSQL 11 to perform CRUD operation, and it works fine for 1. Create 2. Update 3. Delete, but while I run read command by passing Condition = 4 to select a result set, I get below error. I have used PostgreSQL function to get result set it works for me, but I need to get result using the PostgreSQL stored procedure. Here is my code for stored procedure: CREATE OR REPLACE PROCEDURE public.testSpCrud( fnam text, lnam text, id integer, condition integer)

问题 I created a stored procedure in PostgreSQL 11 to perform CRUD operation, and it works fine for 1. Create 2. Update 3. Delete, but while I run read command by passing Condition = 4 to select a result set, I get below error. I have used PostgreSQL function to get result set it works for me, but I need to get result using the PostgreSQL stored procedure. Here is my code for stored procedure: CREATE OR REPLACE PROCEDURE public.testSpCrud( fnam text, lnam text, id integer, condition integer)

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 5 years ago . Improve this question I understand that using that function will make an entire string all lowercase. However, I'm curious in the behind the scenes work. I can't find an explanation anywhere on how it works. Does it basically loop through every index in the string and check to see

问题 I'm trying to understand this code istream &read(istream &is, Sales_data &item) { double price = 0; is >> item.bookNo >> item.units_sold >> price; item.revenue = price * item.units_sold; return is; } ostream &print(ostream &os, const Sales_data &item) { os << item.isbn() << " " << item.units_sold << " " << item.revenue << " " << item.avg_price(); return os; } I don't understand what are these function , also I can't understand why we use istream for reading and ostream for printing instead of