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Tag: syntax

Comma Syntax: rationale behind a hanging comma in a statement being a SyntaxError

In Python, a variable or literal followed by a hanging comma is a one-tuple: …and a series of comma-separated variables/literals (whether or not they are followed by a hanging comma) is also a tuple: However, inside a callable/function, this syntax is treated differently, because the comma is used for separation of arguments: The first line seems to simply ignore the

Inline for loop

I’m trying to learn neat pythonic ways of doing things, and was wondering why my for loop cannot be refactored this way: I tried replacing the for loop with: But it doesn’t work. The for v in vm: loop evicts numbers from vm based on when they come next in q. Answer What you are using is called a list

Python “raise from” usage

What’s the difference between raise and raise from in Python? which yields and which yields Answer The difference is that when you use from, the __cause__ attribute is set and the message states that the exception was directly caused by. If you omit the from then no __cause__ is set, but the __context__ attribute may be set as well, and

Extracting specific columns in numpy array

This is an easy question but say I have an MxN matrix. All I want to do is extract specific columns and store them in another numpy array but I get invalid syntax errors. Here is the code: It seems like the above line should suffice but I guess not. I looked around but couldn’t find anything syntax wise regarding

What’s the difference between “2*2” and “2**2” in Python?

What is the difference between the following statements? Statement 1: Statement 2: I see no difference. This raises the following question. Why is Statement 1 used if we can use Statement 2? Answer Try: and to see the difference. ** is the operator for “power of”. In your particular operation, 2 to the power of 2 yields the same as