python-3.x - GeoPandas dataFrame using iterrows() to fill a dictionary with column data

Question

I am using pandas DataFrame to make a nested dictionary with a column that contains names. Each dictionary element is a nested dictionary and each nested dictionary's key is a name from the DataFrame column.

I am using this line to fill the dictionary:

for row, name in map_datafile.iterrows():         
    material_count[name._get_value(label='NAME')] = {}

For some reason, the resulting dictionary contains only 579 of the 586 names contained in the DataFrame. For this reason, when I go to add a column with new data that I calculated from this dictionary, I get this error:

ValueError: Length of values does not match length of index

Indicating that the length of the values to be inserted into the DataFrame is different than the DataFrame.

Am I filling the dictionary incorrectly? Any advice on this issue would be great, I am new to DataFrames.

标签： python-3.xdataframedictionarygeopandas

Answer 1

.iterrows()返回索引，然后返回行。
此外，您可以使用不同的语法来访问该值，而不是调用._get_value().
所以你可以这样做：

for idx, row in map_datafile.iterrows():         
    material_count[row['NAME']] = {}

您也可以这样做（可能更快）：

material_count = {k:{} for k in map_datafile['NAME'].to_list()}