python浮动对象不支持项目分配答案

【问题标题】：python float object does not support item assignmentpython浮动对象不支持项目分配
【发布时间】：2018-03-13 05:20:43
【问题描述】：

我正在运行以下代码，但收到错误消息“浮动”对象不支持项目分配。我想要的输出是将这些计算的结果附加到向量 Vi 中

import numpy as np

MolWeight = [132, 320, 29, 45, 10]
Ci = 10 # g/L initial Concentration
Cf = 50*10**(-6) #M final Concentration
Vf = 100*10**(-6) #Litre final Volume
Vi = []
for i in range(len(MolWeight)):
    #How many moles of the compounds are there in the standard solution
    Mi = Ci/MolWeight[i] #M
    #this corresponds to the initial concentration of the standard     compound
    Ci = Mi #M/L
    #I calculate the volume to extract from the standard compound    solution, so to obtain the desired concentration 
    np.append.Vi[i] = (Cf*Vf)/Ci #L

【问题讨论】：

@Evert 附加大括号错误Vi[i].append(Cf*Vf/Ci)。但正确的建议。

标签： python object variable-assignment

【解决方案1】：

这就是你要找的吗？我认为问题是 int 除法和追加

import numpy as np

MolWeight = [132.0, 320.0, 29.0, 45.0, 10.0]
Ci = 10.0 # g/L initial Concentration
Cf = 50*10**(-6) #M final Concentration
Vf = 100*10**(-6) #Litre final Volume
Vi = []
for i in range(len(MolWeight)):
    #How many moles of the compounds are there in the standard solution
    Mi = Ci/MolWeight[i] #M
    #this corresponds to the initial concentration of the standard     compound
    Ci = Mi  # M/L
    #I calculate the volume to extract from the standard compound    solution, so to obtain the desired concentration 
    # np.append.Vi[i] = (Cf * Vf) / Ci  # L
    Vi.append((Cf * Vf) / Ci )


print Vi

输出

 [6.599999999999998e-08, 2.1119999999999998e-05, 0.0006124799999999999, 0.027561599999999995, 0.27561599999999997]

【讨论】：

【解决方案2】：

你可以这样做

Vi.append((Cf*Vf)/Ci) #L

输出：

Vi
[6.599999999999998e-08,
 2.1119999999999998e-05,
 0.0006124799999999999,
 0.027561599999999995,
 0.27561599999999997]

【讨论】：