Python 3.x 熊猫：使用单独数据框中一个单元格的值填充数据框列中的所有行

我想用单独数据框中一个单元格的值填充dataframe列中的所有行

两个dfs都基于从同一CSV读取的数据

data_description = pd.read_csv(file.csv, nrows=1) 

#this two rows of data: one row of column headers and one row of values. The value I want to use later is under the header "average duration"

data_table = pd.read_csv(file.csv, skiprows=3) 

#this is a multi row data table located directly below the description. I to want add a "duration" column will all rows populated by "average duration" from above.

df1 = pd.DataFrame(data_description)
df2 = pd.DataFram(data_table)

df2['duration'] = df1['average duration']

最后一行仅适用于列中的第一个from。如何向下延伸所有行

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如果我直接分配“平均持续时间”值，它会工作，例如，

df2['duration']=60

，但我希望它是动态的。

您必须从df1中提取值，然后将值分配给df2。分配的是一个系列，而不是值

data_description = pd.read_csv(file.csv, nrows=1) 

data_table = pd.read_csv(file.csv, skiprows=3) 

df1 = pd.DataFrame(data_description)
df2 = pd.DataFram(data_table)

df2['duration'] = df1['average duration'][0]

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我怀疑这会很简单。谢谢