在添加的列上获取nan

Question

在dataframerebinnedDF中，我想添加另一个具有重复随机行值的列。我将该值创建为repeateArray

    year2014_bin    year2015_bin    year2016_bin    year2017_bin
0   binZ            binZ             binZ           binZ
1   binZ            binZ              binZ           binZ   
repeateArray=[x for x in range (0, rebinnedDF.shape[0]/len(rebinnedDF.columns))]

repeateArray =rebinnedDF.join(pd.DataFrame (repeateArray))

当我做repeateArray[0][:2]这是添加的列时，我得到nan。根据上面的列表理解不应该有价值

    year2014_bin    year2015_bin    year2016_bin    year2017_bin    0
0   binZ            binZ            binZ            binZ           nan
1   binZ            binZ            binZ            binZ           nan


4   binZ            binZ           binZ             binZ           nan
5   binZ            binZ           binZ             binZ           nan
6   binZ            binZ           binZ             binZ           nan
7   binZ            binZ           binZ             binZ          nan
8   binZ            binZ           binZ             binZ           nan
9   binZ            binZ           binZ              binZ        nan


Desired. I want `0` to be randomly repeated based on the length of the dataframe. I have 6 million rows. Number of repetition really does not matter. 

    year2014_bin    year2015_bin    year2016_bin    year2017_bin    0
0   binZ            binZ            binZ             binZ           1
1   binZ            binZ            binZ             binZ           2
2   binZ            binZ            binZ             binZ           3
3   binZ            binZ            binZ             binZ           4
4   binZ            binZ            binZ             binZ           1
.............