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- python - How to check for NaN values - Stack Overflow
@TMWP: If you're using NumPy, numpy isnan is a superior choice, as it handles NumPy arrays If you're not using NumPy, there's no benefit to taking a NumPy dependency and spending the time to load NumPy just for a NaN check (but if you're writing the kind of code that does NaN checks, it's likely you should be using NumPy)
- How to check the exit status using an if statement
Every command that runs has an exit status That check is looking at the exit status of the command that finished most recently before that line runs If you want your script to exit when that test returns true (the previous command failed) then you put exit 1 (or whatever) inside that if block after the echo That being said, if you are running the command and are wanting to test its output
- if and #if ; which one is better to use - Stack Overflow
if and #if are different things with different purposes If you use the if statement, the condition is evaluated at runtime, and the code for both branches exists within the compiled program The condition can be based on runtime information, such as the state of a variable if is for standard flow control in a program If you use the preprocessor's #if, the condition is evaluated at compile
- What is the purpose of using #ifdef and #if in C++?
#ifdef means if defined If the symbol following #ifdef is defined, either using #define in prior source code or using a compiler command-line argument, the text up to the enclosing #endif is included by the preprocessor and therefore compiled #if works similarly, but it evaluates the boolean expression following it If that expression is true, the code up to the enclosing #endif is included
- How do I check whether a file exists without exceptions?
Note: your program will not be 100% robust if it cannot handle the case where a file already exists or doesn't exist at the time you actually try to open or create it respectively The filesystem is concurrently accessible to multiple programs, so the existance-check you did prior to these actions might already be outdated by the time your program acts on it
- What is Pythons equivalent of (logical-and) in an if-statement?
There is no bitwise negation in Python (just the bitwise inverse operator ~ - but that is not equivalent to not) See also 6 6 Unary arithmetic and bitwise binary operations and 6 7 Binary arithmetic operations The logical operators (like in many other languages) have the advantage that these are short-circuited That means if the first operand already defines the result, then the second
- python - How to exit an if clause - Stack Overflow
What sorts of methods exist for prematurely exiting an if clause? There are times when I'm writing code and want to put a break statement inside of an if clause, only to remember that those can o
- What are the differences between if-else and else-if? [closed]
I am trying to discern the difference between: if else and else if How do you use these? And when do you use them and when not?
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