写入 savetxt/tofile/save 与读取 loadtxt/fromfile/load 保存格式和读取时，dtype 要一致，否则读出的数据可能会乱码
TXTa = list(range(0, 100))
a = np.array(a) # a.dtype = np.int64
np.savetxt("filename.txt", a)
b = np.loadtxt("filename.txt", dtype=np.int64)
BIN
a = list(range(0, 100))
a = np.array(a) # a.dtype = np.int64
a.tofile("filename.bin", a)
b = np.fromfile("filename.bin", dtype=np.int64)
NPY
a = list(range(0, 100))
a = np.array(a) # a.dtype = np.int64
np.save("filename.npy", a)
b = np.load("filename.npy", dtype=np.int64)
番外
读取字符串文件genfromtxt
'''
file.txt
123 456
aaa
'''
a = np.genfromtxt('file.txt', dtype='str', skip_header=1)
# 跳过开头第一行，以字符串读取文件，a = array(['aaa', 'bbb', 'ccc', 'ddd'], dtype='
