Martijn’s answer explains what None is in Python, and correctly states that the book is misleading. Since Python programmers as a rule would never say Assigning a value of None to a variable is one way to reset it to its original, empty state. it’s hard to explain what Briggs means in a way which … Read more
If you mean a minimal form, go with this: if (not a or not b or not c) and (a or b or c): Which translates the title of your question. UPDATE: as correctly said by Volatility and Supr, you can apply De Morgan’s law and obtain equivalent: if (a or b or c) and … Read more
I totally agree with the opinion that premature optimization is something to avoid. But it’s true that the Java VM has special bytecodes which could be used for switch()’s. See WM Spec (lookupswitch and tableswitch) So there could be some performance gains, if the code is part of the performance CPU graph.
Unfortunately, there is no formula way to result in a truly blank cell, “” is the best formulas can offer. I dislike ISBLANK because it will not see cells that only have “” as blanks. Instead I prefer COUNTBLANK, which will count “” as blank, so basically =COUNTBLANK(C1)>0 means that C1 is blank or has … Read more
The documentation for ifelse states: ifelse returns a value with the same shape as test which is filled with elements selected from either yes or no depending on whether the element of test is TRUE or FALSE. Since you are passing test values of length 1, you are getting results of length 1. If you … Read more
This can be useful if there are #if statements, ala if (0) { // Empty block } #if TEST1_ENABLED else if (test1()) { action1(); } #endif #if TEST2_ENABLED else if (test2()) { action2(); } #endif etc. In this case, any (and all) of the tests can be #if‘ed out, and the code will compile correctly. … Read more
As of C++17 what you were trying to do is finally possible: if (int a = Func1(), b = Func2(); a && b) { // Do stuff with a and b. } Note the use of ; of instead of , to separate the declaration and the actual condition.
You should prefer try/except over if/else if that results in speed-ups (for example by preventing extra lookups) cleaner code (fewer lines/easier to read) Often, these go hand-in-hand. speed-ups In the case of trying to find an element in a long list by: try: x = my_list[index] except IndexError: x = ‘NO_ABC’ the try, except is … Read more
Your first step in these kinds of problems is always to make a logic table. A | B | Result ——————- T | T | do action C T | F | … F | T | do action C F | F | do action C Once you’ve made the table, the solution is … Read more
No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write: if (str != null && !str.isEmpty()) { doSomethingWith(str.charAt(0)); } or, the other way around if (str == null || str.isEmpty()) { complainAboutUnusableString(); } else { doSomethingWith(str.charAt(0)); … Read more