"[:，]"列表切片python，这是什么意思? [英] "[:,]" list slicing python, what does it mean?

问题描述

我正在阅读一些代码，看到了" list[:,i] for i in range(0,list))......"

我对在那里的逗号感到迷惑，:,，由于您无法使用Google标点符号，因此google无法提供答案.

任何帮助都将不胜感激！

解决方案

您正在查看 numpy 多维数组切片. /p>

逗号标记一个元组，将其读取为[(:, i)]，numpy数组将其解释为:首先要使用:端到端(所有行)切片的维，然后是每行选择一个列.

请参见numpy教程中的索引，切片和迭代.

I'm reading some code and I see " list[:,i] for i in range(0,list))......"

I am mystified as to what comma is doing in there, :, and google offers no answers as you cant google punctuation.

Any help greatly appreciated!

解决方案

You are looking at numpy multidimensional array slicing.

The comma marks a tuple, read it as [(:, i)], which numpy arrays interpret as: first dimension to be sliced end-to-end (all rows) with :, then for each row, i selects one column.

See Indexing, Slicing and Iterating in the numpy tutorial.

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