operators

问题 I have come from a matlab background to python and i am just wondering if there is a simple operator in python that will perform the following function: a = [1, 0, 0, 1, 0, 0] b = [0, 1, 0, 1, 0, 1] c = a|b print c [1, 1, 0, 1, 0, 1] or would i have to write a separate function to do that? 回答1: You could use a list comprehension. Use izip from itertools if you're using Python 2. c = [x | y for x, y in zip(a, b)] Alternatively, @georg pointed out in a comment that you can import the bitwise or

问题 I have come from a matlab background to python and i am just wondering if there is a simple operator in python that will perform the following function: a = [1, 0, 0, 1, 0, 0] b = [0, 1, 0, 1, 0, 1] c = a|b print c [1, 1, 0, 1, 0, 1] or would i have to write a separate function to do that? 回答1: You could use a list comprehension. Use izip from itertools if you're using Python 2. c = [x | y for x, y in zip(a, b)] Alternatively, @georg pointed out in a comment that you can import the bitwise or

问题 I have the following classes in C++: class Event { //... friend ofstream& operator<<(ofstream& ofs, Event& e); }; class SSHDFailureEvent: public Event { //... friend ofstream& operator<<(ofstream& ofs, SSHDFailureEvent& e); }; The code I want to execute is: main() { Event *e = new SSHDFailureEvent(); ofstream ofs("file"); ofs << *e; } This is a simplification, but what I want to do is write into a file several type of Events in a file. However, instead of using the operator << of

问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: String comparison in Python: is vs. == When is the == operator not equivalent to the is operator? (Python) I'm pretty new to Python still. I heard someone say use is , not == because "this isn't C". But I had some code x is 5 and it was not working as expected. So, following proper Python/PEP style, when is the time to use is and when is the time to use == ? 回答1: You should use == to compare two values. You

问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: String comparison in Python: is vs. == When is the == operator not equivalent to the is operator? (Python) I'm pretty new to Python still. I heard someone say use is , not == because "this isn't C". But I had some code x is 5 and it was not working as expected. So, following proper Python/PEP style, when is the time to use is and when is the time to use == ? 回答1: You should use == to compare two values. You

问题 I'm looking at the docs and trying to understand how the operator actually works. The increment operator (++) increments its operand by 1. The increment operator can appear before or after its operand: ++variable and variable++ . The first form is a prefix increment operation. The result of the operation is the value of the operand after it has been incremented. The second form is a postfix increment operation. The result of the operation is the value of the operand before it has been

问题 I would like to print a message if either a or b is empty. This was my attempt a = "" b = "string" if (a or b) == "": print "Either a or b is empty" But only when both variables contain an empty string does the message print. How do I execute the print statement only when either a or b is an empty string? 回答1: The more explicit solution would be this: if a == '' or b == '': print('Either a or b is empty') In this case you could also check for containment within a tuple: if '' in (a, b): print

问题 I am trying to create a function where users can select the operator they want to use, which result in a different output. But I can't seem to get it to work. I know that we can't assign operators into an R object and then use it as an operator based on the R object name. Is there a way I could do this? Or perhaps a better way to write the function? test <- function(items, operator = "+"){ bank_alpha <- matrix(ncol=6) colnames(bank_alpha) <- colnames(bank_alpha, do.NULL = FALSE, prefix = "Q")

问题 I just know from this github project that Swift has +++ and <<< "operators". It's hard for me to search for this on google because +++ and <<< maybe some kind of special characters and not showing up on search result at all. It's not even showing up on questions that may already have your answer section of Stack Overflow when I wrote the question title. Can you explain briefly what are these weird operators for, and maybe some articles link for further reading? 回答1: Those operators are not a

问题 I just know from this github project that Swift has +++ and <<< "operators". It's hard for me to search for this on google because +++ and <<< maybe some kind of special characters and not showing up on search result at all. It's not even showing up on questions that may already have your answer section of Stack Overflow when I wrote the question title. Can you explain briefly what are these weird operators for, and maybe some articles link for further reading? 回答1: Those operators are not a