Python reverse-stride slicing
Simply exclude the end range index… >>> foo[3::-1] ‘3210’ Ironically, about the only option I think you didn’t try.
slice
Difference between list, sequence and slice in Python?
You’re mixing very different things in your question, so I’ll just answer a different question You are now asking about one of the most important interface in Python: iterable – it’s basically anything you can use like for elem in iterable. iterable has three descendants: sequence, generator and mapping. A sequence is a iterable with … Read more
Why does .loc have inclusive behavior for slices?
Quick answer: It often makes more sense to do end-inclusive slicing when using labels, because it requires less knowledge about other rows in the DataFrame. Whenever you care about labels instead of positions, end-exclusive label slicing introduces position-dependence in a way that can be inconvenient. Longer answer: Any function’s behavior is a trade-off: you favor … Read more
resize with averaging or rebin a numpy 2d array
Here’s an example based on the answer you’ve linked (for clarity): >>> import numpy as np >>> a = np.arange(24).reshape((4,6)) >>> a array([[ 0, 1, 2, 3, 4, 5], [ 6, 7, 8, 9, 10, 11], [12, 13, 14, 15, 16, 17], [18, 19, 20, 21, 22, 23]]) >>> a.reshape((2,a.shape[0]//2,3,-1)).mean(axis=3).mean(1) array([[ 3.5, 5.5, 7.5], [ … Read more
Check whether a string slice contains a certain value in Go
If you have a slice of strings in an arbitrary order, finding if a value exists in the slice requires O(n) time. This applies to all languages. If you intend to do a search over and over again, you can use other data structures to make lookups faster. However, building these structures require at least … Read more
Understanding string reversal via slicing
Sure, the [::] is the extended slice operator. It allows you to take substrings. Basically, it works by specifying which elements you want as [begin:end:step], and it works for all sequences. Two neat things about it: You can omit one or more of the elements and it does “the right thing” Negative numbers for begin, … Read more
Iteration over list slices
If you want to divide a list into slices you can use this trick: list_of_slices = zip(*(iter(the_list),) * slice_size) For example >>> zip(*(iter(range(10)),) * 3) [(0, 1, 2), (3, 4, 5), (6, 7, 8)] If the number of items is not dividable by the slice size and you want to pad the list with None … Read more
Pandas slicing FutureWarning with 0.21.0
TL;DR: There is likely a typo or spelling error in the column header names. This is a change introduced in v0.21.1, and has been explained in the docs at length – Previously, selecting with a list of labels, where one or more labels were missing would always succeed, returning NaN for missing labels. This will … Read more
Slice chunking in Go
You don’t need to make new slices, just append slices of logs to the divided slice. http://play.golang.org/p/vyihJZlDVy var divided [][]string chunkSize := (len(logs) + numCPU – 1) / numCPU for i := 0; i < len(logs); i += chunkSize { end := i + chunkSize if end > len(logs) { end = len(logs) } divided … Read more
Go Pointers – append values to slice via pointer
append returns a reference to the appended-to slice. This is because it could point to a new location in memory if it needed to be resized. In your first example, you are updating the variable passed to your setAttribute function, but that’s it. The only reference is lost when that function exits. It works in … Read more