pandas：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
pandas: populate all rows in a dataframe column with the values from one cell in a separate data frame
我想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。
两个 dfs 都基于从同一个 CSV 中读入的数据。
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行。如何向下扩展所有行？
如果我直接分配 'average duration' 值，它就可以工作，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。您分配的是系列，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]
我想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。
两个 dfs 都基于从同一个 CSV 中读入的数据。
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行。如何向下扩展所有行？
如果我直接分配 'average duration' 值，它就可以工作，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。您分配的是系列，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]