Python Numpy的哪里有日期时间功能 [英] Python numpy where function with datetime

问题描述

我有一系列30年的每日约会时间.我试图使用np.where按月和日过滤此数组，以便可以找到一年中每一天对应数据条目的平均值.

I have an array of daily date times over a period of 30 years. I am trying to filter this array by month and day using np.where so that I can find the average of the corresponding data entries for each day of the year.

但是，我得到了错误:

AttributeError: 'list' object has no attribute 'month'

我可以在执行以下操作时正确查询数据:

I can query the data correctly when I do:

print "dates[100].month: ", dates[100].month

我可以使用numpy where函数查询datetime条目吗?

Is there any way I can use the numpy where function to query datetime entries?

到目前为止，我的代码是:

The code I have so far is:

clim = np.zeros((12,31))

m_arr = range(1,13)  # months array
d_arr = range(1,32)  # days array

for i in range(len(m_arr)):

for j in range(len(d_arr)):

    # finding indexes of the dates array

    tt, = np.where((dates.month == i) & (dates.day == j))
    data2 = np.zeros(len(tt))
    dates2 = np.zeros(len(tt))

    if len(tt) > 0:

    for num in range(len(tt)):

                site = tt[num]
            dates2[num] = dates[site]
        data2[num] = data[site]

        clim[i,j]=data2[~np.isnan(data2)].mean()      # some nan entries in data

推荐答案

由于dates是 list ，因此即使其元素为datetime，也不能将其用作datetime.类型.因此，而不是

Since dates is a list, it cannot be used as a datetime, even if its elements are datetime type. So instead of

dates.month == i

您需要类似的东西

[d.month == i for d in months]

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