Data classes are just regular classes that are geared towards storing state, rather than containing a lot of logic. Every time you create a class that mostly consists of attributes, you make a data class. What the dataclasses module does is to make it easier to create data classes. It takes care of a lot … Read more
In Python 2.x: range creates a list, so if you do range(1, 10000000) it creates a list in memory with 9999999 elements. xrange is a sequence object that evaluates lazily. In Python 3: range does the equivalent of Python 2’s xrange. To get the list, you have to explicitly use list(range(…)). xrange no longer exists.
The exponential function is e^x where e is a mathematical constant called Euler’s number, approximately 2.718281. This value has a close mathematical relationship with pi and the slope of the curve e^x is equal to its value at every point. np.exp() calculates e^x for each value of x in your input array.
Using an additional state variable, such as an index variable (which you would normally use in languages such as C or PHP), is considered non-pythonic. The better option is to use the built-in function enumerate(), available in both Python 2 and 3:
The uuid module provides immutable UUID objects (the UUID class) and the functions uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5 UUIDs as specified in RFC 4122. If all you want is a unique ID, you should probably call uuid1() or uuid4(). Note that uuid1() may compromise privacy since it creates a UUID containing … Read more
As others have pointed out, due to not using understandable variable names, it is almost impossible to debug your code. Following the wiki article about Dijkstra’s algorithm, one can implement it along these lines (and in a million other manners): This code is more verbous than necessary and I hope comparing your code with mine … Read more
Reference: Data Structures > More on Lists Caveats follow Note that while this is perhaps the cleanest way to answer the question as asked, index is a rather weak component of the list API, and I can’t remember the last time I used it in anger. It’s been pointed out to me in the comments that because this answer is heavily … Read more
Let’s say you’re opening the file with a with statement like you should be. Then you’d do something like this to read from your file: Note the f.seek(0) — if you forget this, the f.read() call will try to read from the end of the file, and will return an empty string.
To delimit by a tab you can use the sep argument of to_csv: To use a specific encoding (e.g. ‘utf-8’) use the encoding argument:
Somewhere else in your code you have something that looks like this: Then when you write that is interpreted as meaning a function call on the object bound to round, which is an int. And that fails. The problem is whatever code binds an int to the name round. Find that and remove it.