iteration

问题 I have a list created with no more than 8 items in it, right now I loop over the item with a standard for loop "for item in list:" I am wondering if there is a way to check all of the elements at the exact same time? I have seen some posts about using zip to iterate over 2 lists at the same time which could help. If there is no way to iterate over a lists elements at the same time I would guess I need to split one single list into 4 separate lists and iterate 2 at the same time using zip and

问题 I bombed an interview (phone screen with collabedit) recently. Here is the question: Write an interative O(lg n) algorithm for finding the power of x^y (x is a double, y>0 is an int). I first did the recursive divide and conquer one and tried to convert it to iterative... and I couldn't :S Is there a method to convert recursion to iterative (it is easy for tail recursion, but how about recursive functions with two possible recursive calls which depend on conditions to decide which call will

问题 I bombed an interview (phone screen with collabedit) recently. Here is the question: Write an interative O(lg n) algorithm for finding the power of x^y (x is a double, y>0 is an int). I first did the recursive divide and conquer one and tried to convert it to iterative... and I couldn't :S Is there a method to convert recursion to iterative (it is easy for tail recursion, but how about recursive functions with two possible recursive calls which depend on conditions to decide which call will

问题 This is what my JSON array of objects looks like: [ { "Description": "Description 1", "OutputKey": "OutputKey 1", "OutputValue": "OutputValue 1" }, { "Description": "Description 2", "OutputKey": "OutputKey 2", "OutputValue": "OutputValue 2" }, { "Description": "Description 3", "OutputKey": "OutputKey 3", "OutputValue": "OutputValue 3" }, { "Description": "Description 4", "OutputKey": "OutputKey 4", "OutputValue": "OutputValue 4" }, { "Description": "Description 5", "OutputKey": "OutputKey 5",

问题 I've seen a lot of different examples of how to do this and am well aware that I could write out a loop that iterates my entire tree of classes to find the maximum depth, but I cannot help but think there has to be a simpler way. Basically I have two classes that I developed to host all my applications settings, SettingGroup which is exactly what it sounds like, basically a folder, and Setting which is the setting itself and the configurations that allow the application to know what the

问题 I have CSV files with comments that give column names, where the columns change throughout the file: #c1,c2,c3 a,b,c d,e,f #c4,c5 g,h i,j I want to provide a way to iterate over (only) the data rows of the file as Maps of column names to values (all Strings). So the above would become: Map(c1 -> a, c2 -> b, c3 -> c) Map(c1 -> d, c2 -> e, c3 -> f) Map(c4 -> g, c5 -> h) Map(c4 -> i, c5 -> j) The files are very large, so reading everything into memory is not an option. Right now I have an

问题 I have a dataframe df with 6 fields A,B,C,D,E & F. My requirement is to create a new column G which is equal to the previous value(C) + previous value(D) + previous (G) - F. But this needs to be implemented at a group level through columns A & B (group by A & B). In case it is the first row within the group then the value in column G should be equal to E. Sample Df - A B C D E F 1 2 100 200 300 0 1 2 110 210 310 10 1 2 120 130 300 10 1 1 140 150 80 0 1 1 50 60 80 20 1 1 50 60 80 20 Output - A

问题 Below I have added my game of life code. The rules are defined correctly, and it runs smoothly. However, the game does not work as supposed. It is not updating to the next generation, but it seems to be overwriting the current generation. As an example: Three horizontal dots are supposed to turn into three vertical dots in the next generation, but this does not happen. The solution: I have two generations, the current and the next generation. It has to apply the rules to the current

问题 Excuse me if this has been asked before. My search did not bring up any other similar question. This is something that surprised me in Java. Apparently, the enhanced for-loop only accepts an array or an instance of java.lang.Iterable . It does not accept a java.util.Iterator as a valid obj reference to iterate over. For example, Eclipse shows an error message for the following code. It says: " Can only iterate over an array or an instance of java.lang.Iterable " Set<String> mySet = new

问题 Excuse me if this has been asked before. My search did not bring up any other similar question. This is something that surprised me in Java. Apparently, the enhanced for-loop only accepts an array or an instance of java.lang.Iterable . It does not accept a java.util.Iterator as a valid obj reference to iterate over. For example, Eclipse shows an error message for the following code. It says: " Can only iterate over an array or an instance of java.lang.Iterable " Set<String> mySet = new