在python中导入数组 [英] import an array in python

问题描述

如何从文件中将数组导入python(numpy.arry)，并且如果该文件不存在，则必须将该文件写入.

How can I import an array to python (numpy.arry) from a file and that way the file must be written if it doesn't already exist.

例如，将矩阵保存到文件中，然后将其重新加载.

For example, save out a matrix to a file then load it back.

推荐答案

检出 numpy示例列表上的条目.这是.loadtxt()上的条目

Checkout the entry on the numpy example list. Here is the entry on .loadtxt()

>>> from numpy import *
>>>
>>> data = loadtxt("myfile.txt")                       # myfile.txt contains 4 columns of numbers
>>> t,z = data[:,0], data[:,3]                         # data is 2D numpy array
>>>
>>> t,x,y,z = loadtxt("myfile.txt", unpack=True)                  # to unpack all columns
>>> t,z = loadtxt("myfile.txt", usecols = (0,3), unpack=True)     # to select just a few columns
>>> data = loadtxt("myfile.txt", skiprows = 7)                    # to skip 7 rows from top of file
>>> data = loadtxt("myfile.txt", comments = '!')                  # use '!' as comment char instead of '#'
>>> data = loadtxt("myfile.txt", delimiter=';')                   # use ';' as column separator instead of whitespace
>>> data = loadtxt("myfile.txt", dtype = int)                     # file contains integers instead of floats

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