if-statement

问题 I have 4 text files in the following formats keycountry.txt UK USA Germany country.txt Brexit - UK USA UK Relations France win world cup keylink.txt www.abc.com www.ddd.com www.eee.com link.txt www.abc.com www.eee.com The code: import re keycountryfile = "keycountry.txt" countryfile = "country.txt" links = open('links.txt', 'r') links_data = links.read() links.close() keys = open('keylink.txt', 'r') keys_data = keys.read() keys.close() keys_split = keys_data.splitlines() print('LINKS') for

问题 boolean flag = false; if(!flag) System.out.println(!flag); // prints true I wonder why !flag being considered as false when it's a conditional parameter passed to if statement and as true elsewhere? 回答1: It's not. if (boolean expression) { statement } means "execute the statement if boolean expression is true." Since flag = false , !flag == true . Always. 回答2: !flag where flag is false evaluates to true in all contexts, including if statements. 回答3: !flag does not change the value of flag ,

问题 I'm making a small program that uses a if else statement, but instead of using numbers to control the flow i want to be able to make the control work with with yes and no; for example: cout << "would you like to continue?" << endl; cout << "\nYES or NO" << endl; int input =0; cin >> input; string Yes = "YES"; string No = "NO"; if (input == no) { cout << "testone" << endl; } if (input == yes) { cout << "test two" << endl; //the rest of the program goes here i guess? } else { cout << "you

问题 I have one table called Master and it has four columns called id , A , B and C . When I update the table, I need to modify the specific single column that a user selected. For example, if a user selected column A then only A records will get updated in the database. If the user selects C then only C records will updated. Below is the code I tried, but it is updating all columns. Would you help me in this? $column_name=$row['column_name'];//A,B,C if (isset($result->num_rows) > 0) { // output

问题 Calculation inside for loop & ifelse is working when I have 100-200 rows but not working when I have 20000 rows. Can someone help me with the FOR loop and IFELSE if something is wrong or if there is some timeout happening in R studio when running for & if-else loop Code: #FROM HERE IT IS NOT WORKING WHEN WE HAVE 20000 ROWS OF DATA IN FINAL DATFRAME. #WE ARE CREATING FINAL_V1 WHICH IS POPULATING ONLY 1 ROW #New Dataframe with Null values Final <- structure(list(Item = structure(c(1L, 1L, 1L,

问题 I am trying to refactor this code I have below that uses several nested if statements to check if two list contains the same items. List<Car> CarList = CarService.findCarByConfigtype(pageName); for (int i = 0; i < CarList.size(); i++) { System.out.println(CarRestApiController.data().getModel()); if (CarList.get(i).getModel().equals(CarRestApiController.data().getModel())) { dataFound.add(CarList.get(i).getModel()); if (CarList.get(i).getDerivative().equals(CarRestApiController.data()

问题 Good morning I have a dataset of fisheries data with several variables that look like this: ID Day Month Year Depth Haul number Count LengthClass H111200840 11 1 2008 -80 40 4 10-20 H111200840 11 1 2008 -80 40 15 20-30 H29320105 29 3 2010 -40 5 3 50-60 H29320105 29 3 2010 -40 5 8 60-70 The column ID is a unique ID made by paste the columns day,month,Year and Haul.number. As you can see for the same ID I have data of different Length Class. En each Haul, fish from different lengths are

问题 use "locationdata.dta", clear gen ring=. * Philly City Hall gen lat_center = 39.9525468 gen lon_center = -75.1638855 destring(INTPTLAT10), replace destring(INTPTLON10), replace vincenty INTPTLAT10 INTPTLON10 lat_center lon_center , hav(distance_km) inkm quietly su distance_km local min = r(min) replace ring=0 if (`min' <= distance_km < 1) local max = ceil(r(max)) * forval loop does not work forval i=1/`max'{ local j = `i'+1 replace ring=`i' if (`i' <= distance_km < `j') } I am drawing rings

问题 This has been updated to clarify the question so it can better help others in the future. I am attempting to use an if statement to test if the key classes exists in a JSON structure using Python. to check if a key exists in a JSON structure using Python. I am able to get the key but need help finding out what the condition should be to check if it exists. I successfully was able to return the value of the key class when it is exsits in the JSON structure using the following code: #Parameter:

问题 So, I'm making this program to help study for my Japanese class. As you may be able to see it shuffles a list of words and displays them. Then the program asks for a translation. It's supposed to check if the answer is correct or not and display the appropriate message. However, regardless of whether the answer is correct or not it will display all of the "incorrect" messages. My question is how to fix this issue. Please, I need help, and I would like to finish this before I take the next