if-statement

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: python, basic question on loops how to let a raw_input repeat until I wanna quit? I would like some help with Python please. I'm writing a program in Py2.7.2, but am having some issues. What I have so far is something like this: choice = raw_input("What would you like to do") if choice == '1': print("You chose 1") elif choice == '2': print("You chose 2") elif choice == '3': print("You chose 3") else: print("That

问题 I'm defining a function for solving my differential equations in scipy's solve_ivp. def conv(t,Z): global sw,von,X if sw==0 and X[1]>=von or sw==1 and X[0]>0: zdot=LA.inv(v1).dot(A1).dot(v1).dot(Z).reshape(4,1)+LA.inv(v1).dot(B1).dot(U) sw=1 von=0.7 X=v1.dot(Z) else: zdot= LA.inv(v0).dot(A0).dot(v0).dot(Z).reshape(4,1)+LA.inv(v0).dot(B0).dot(U) sw=0 X=v0.dot(Z) return np.squeeze(np.asarray(zdot)) and solving my equation using sw=0 e1,v1=LA.eig(A1) von=0 Z= np.array([0, 0, 0, 0]) X=v1.dot(Z) U

问题 Hi there I am expanding on my previous post: Jquery matching values. I was wondering if anyone knows how to have this also filter the ID or Class as it is doing with the data value. I am trying to build a filter like this in the end and have repeating elements show how many times they are repeated. I use TWIG for the HTML from Advanced Custom Fields Wordpress plugin. Eventually I want this to be a dropdown like: https://i.stack.imgur.com/I06cT.png you can refer to this post: Building a

问题 This may be a stupid question, but I just want to somebody can give a better explanation. I have a method defined as below: private int Test(int i) { if (i < 0) return -1; if (i == 0) return 0; if (i > 0) return 1; //return 0; } It gives me this error "not all code path return a value". I thought I had 3 if statement , which could cover all the scenarios(i<0, i==0, i>0). So it should not show me this error. 回答1: The compiler just ain't that clever. Also, you're code is slightly inefficient in

问题 This may be a stupid question, but I just want to somebody can give a better explanation. I have a method defined as below: private int Test(int i) { if (i < 0) return -1; if (i == 0) return 0; if (i > 0) return 1; //return 0; } It gives me this error "not all code path return a value". I thought I had 3 if statement , which could cover all the scenarios(i<0, i==0, i>0). So it should not show me this error. 回答1: The compiler just ain't that clever. Also, you're code is slightly inefficient in

问题 basically I'm quite new to python so I decided to make a simple calculator, I have done the coding for the calculator and that all works and I am happy, however I would like an if-else statement to see if they would like to continue with another calculation. So this is the top part of my code and the bottom part of my code, I would like to know how to get it so that after the 'else' part of the code, it just runs the rest of the code. import os done = ("") if done == True: os._exit(0) else:

问题 Suppose I have an IF condition : if (A || B) ∧ | | left { // do something } Now suppose that A is more likely to receive a true value then B , why do I care which one is on the left ? If I put both of them in the IF brackets , then I know (as the programmer of the code) that both parties are needed . The thing is , that my professor wrote on his lecture notes that I should put the "more likely variable to receive a true" on the left . Can someone please explain the benefit ? okay , I put it

问题 As the topic, how do I manipulate the data from the flat file before loading them onto teradata database using BTEQ script.... I'm unsure which part should the manipulation be written onto the bteq script.... USING ------------------------------------------------------ INSERT INTO ------------------------------------------------------ Values In my opinion, data manipulation should be done here ------------------------------------------------------ Table Name : Jerry A ------- | 5 | | 6 | | 7

问题 I am trying to use a loop for iterating through two lists. Unfortunately, the second for loop does not work: it only checks the first item within the list, but not with rest. Could you please tell me why? Thanks Lists: low_cars_engines=['Audi', 'Bentley', 'Bugatti', 'Porsche', 'Skoda'] low_planes_engines=['Pratt & Whitney','Rolls-Royce','GE Aviation'] I would like to add two more columns (Cars and Planes) to my original dataset based on if statements: if an object from list 'Engine to check'

问题 This is house$room type<-c('2室1厅','2室2厅','3室2厅','1室1厅','4室2厅', '3室1厅','1室','2室','1室2厅','5室2厅','4室3厅') Why does ifelse return only numbers? 回答1: It could be that house$room is factor and it gets coerced to integer storage values within the ifelse loop. One option is to convert to character class ifelse(house$room %in% type, as.character(house$room), '不要张贴图片') 来源： https://stackoverflow.com/questions/49586086/r-ifelse-statement-only-return-number