如何在python中将数组附加到文本文件中

Question

我正在尝试创建一个包含多行作为标题的文件并附加一列数字。我有一些问题在标题后添加numpy.matrix。我写了一个代码如下

import numpy as np
import pandas as pd
import xlrd

df = pd.read_csv('Region_SGeMS.csv', header=None)

matrix = np.asmatrix(df)

#print(matrix)

s = np.shape(matrix)
print(s)
row = s[0]
col = s[1]

a = np.flip(matrix, 0)

b = np.reshape(a, (400, 1))

print(b)

f = open('Region.txt', 'w')

f.write(str(s[0]))
f.write(' ')
f.write(str(s[1]))
f.write(' 1 \n')
f.write('1 \n')
f.write('facies \n')

with open('Region.txt', 'a+') as outfile:
    np.savetxt(outfile,b) 

但是，突出显示的数字应为2，而不是0.我还附上了原始excel文件的屏幕截图。 Here is a screenshot of my result

Answer 1

请注意，如果您允许，numpy.savetxt会为您附加一个标题字符串。例如：

import numpy as np
# Recreate the original csv data
one_block = np.ones((10,10))
A   = np.block([ [0*one_block,one_block],[2*one_block,3*one_block] ])
M,N = A.shape
# Recreate b
a   = np.flip(A,0)
b   = a.reshape(400,1)
hdr_str = """{M:d} {N:d} 1
1
facies""".format(M=M,N=N)
outfile = 'Region.txt'
np.savetxt(outfile,b,header=hdr_str,comments='')

下面是我尝试重新创建问题的屏幕截图。没有虚假的0。

Answer 2

f = open('Region.txt', 'w')
f.write('first line \n')
f.write('second line \n')
f.close()

with open('Region.txt', 'a+') as outfile:
    np.savetxt(outfile,np.random.rand(10,3))