python3.5的numpy設(shè)置array為float64，報錯"name float64 is not defined"

trainWeights = gradDescent(np.array(trainingSet,dtype=float64), trainingLabels)

把dtype設(shè)置為float64會報錯 NameError: name 'float64' is not defined

但是如果去掉"dtype=float64"會出現(xiàn)warning：DataConversionWarning: Data with input dtype <U3 was converted to float64 by MinMaxScaler.

warnings.warn(msg, DataConversionWarning) 提醒被轉(zhuǎn)換成了float64

請問應(yīng)該如何顯式轉(zhuǎn)換呢？

float64是numpy下的一個類，你如果想要前面不加修飾的使用float64需要這樣導(dǎo)入

import numpy as np
from numpy import float64

答：float64是numpy下的一個類，你如果想要前面不加修飾的使用float64需要這樣導(dǎo)入

import numpy as np
from numpy import float64

c = np.array([], dtype=float64)

如果沒有from numpy import float64，使用時要這樣

c = np.array([], dtype=np.float64)