如何读取文本文件，以便在Python中生成浮点数组

Question

How to read a text file where each line has three floating point numbers, each with three digits after the decimal point. The numbers are separated by commas followed by one or more white spaces. The text file (first four observations) looks like this:

-0.340, 1.572, 0.616
-0.948, 1.701, 0.377
 0.105, 2.426, 1.265
-0.509, 2.668, 1.079

Desired output:

array = [[-0.340 1.572 0.616],
[-0.948 1.701 0.377],
[0.105 2.426 1.265],
[-0.509 2.668 1.079]]

Answer 1

fh = open("YourFileName")
raw = fh.read()
fh.close()
data = [[float(i) for i in k.split(",")] for k in raw.split("\n")]

Answer 2

Use the csv module & convert to float, it's simple:

import csv

with open("test.csv") as f:
    array = [[float(x) for x in row] for row in csv.reader(f)]

on this simple case you can get the same result without csv:

    array = [[float(x) for x in row.split(",")] for row in f]

in both cases result is:

[[-0.34, 1.572, 0.616], [-0.948, 1.701, 0.377], [0.105, 2.426, 1.265], [-0.509, 2.668, 1.079]]

Answer 3

Use numpy load text as:

import numpy as np
x= np.loadtxt('YOUR_TXT_FILE.txt',comments='#',usecols=(0),unpack=True)

Answer 4

You should read the whole file, split into lines, and then split each line into values separated by comma. Last thing - use numpy.array to turn it into an array:

import numpy as np

filename = r'****.txt'

with open(filename) as f:
    txt = f.read()
    ls = []
    for line in txt.split('\n'):
        sub_ls = line.split(',')
        ls.append(sub_ls)

    print np.array(ls, dtype=np.float)
    # omitting the ", dtype=np.float" would result in a list-of-strings array

OUTPUT:

[[-0.34   1.572  0.616]
 [-0.948  1.701  0.377]
 [ 0.105  2.426  1.265]
 [-0.509  2.668  1.079]]

Answer 5

Just use numpy.

import numpy as np

arr= np.loadtxt('data.txt',delimiter=',')
print("arr = {}".format(arr))

'''
arr = [[-0.34   1.572  0.616]
 [-0.948  1.701  0.377]
 [ 0.105  2.426  1.265]
 [-0.509  2.668  1.079]]
'''