我正在尝试对数据集进行递归以找到最高级别的项目,即没有父项的项目.
结构如下:
╔════════════╦════════════╗
║ Item ║ Material ║
╠════════════╬════════════╣
║ 2094-00003 ║ MHY00007 ║
║ 2105-0001 ║ 2105-0002 ║
║ 2105-0002 ║ 2105-1000 ║
║ 2105-1000 ║ 2105-1003 ║
║ 2105-1003 ║ 7547-122 ║
║ 7932-00001 ║ 7932-00015 ║
║ 7932-00002 ║ 7932-00015 ║
║ 7932-00010 ║ MHY00007 ║
║ 7932-00015 ║ 7932-05000 ║
║ 7932-05000 ║ MHY00007 ║
╚════════════╩════════════╝
因此,例如,如果我选择7547-122,则该函数将返回2105-0001.因此,函数向上递归地跟随树,7547-122-> 2105-1003-> 2105-1000-> …-> 2105-0001.
如我从MHY00007案例所见,运行代码时,我只能使它返回一个顶层.有时,有多个顶层.如何返回给定材料具有的所有顶层的列表?
我的代码:
import pandas as pd
class BillOfMaterials:
def __init__(self, bom_excel_path):
self.df = pd.read_excel(bom_excel_path)
self.df = self.df[['Item', 'Material']]
def find_parents(self, part_number):
material_parent_search = self.df[self.df.Material == part_number]
parents = list(set(material_parent_search['Item']))
return parents
def find_top_levels(self, parents):
top_levels = self.__ancestor_finder_([parents])
print(f'{parents} top level is {top_levels}')
return {parents: top_levels}
def __ancestor_finder_(self, list_of_items):
for ancestor in list_of_items:
print(f'Searching for ancestors of {ancestor}')
ancestors = self.find_parents(ancestor)
print(f'{ancestor} has ancestor(s) {ancestors}')
if not ancestors:
return ancestor
else:
highest_level = self.__ancestor_finder_(ancestors)
return highest_level
BOM = BillOfMaterials(bom_excel_path="Path/To/Excel/File/BOM.xlsx")
ItemsToSearch = ['7547-122', 'MHY00007']
top_levels = []
for item in ItemsToSearch:
top_levels.append(BOM.find_top_levels(item))
解决方法:
是的,您可以递归执行此操作,例如:
import pandas as pd
class BillOfMaterials:
def __init__(self, bom_excel_path):
self.df = pd.read_excel(bom_excel_path)
self.df = self.df[['Item', 'Material']]
def find_parents(self, part_number):
return list(set(self.df[self.df.Material == part_number]['Item']))
def find_top_levels(self, item):
parents = self.find_parents(item)
if not parents:
# there are no parent items => this item is a leaf
return [item]
else:
# there are parent items => recursively find grandparents
grandparents = []
for parent in parents:
grandparents = grandparents + self.find_top_levels(parent)
return grandparents
if __name__ == '__main__':
BOM = BillOfMaterials(bom_excel_path="testdata.xlsx")
ItemsToSearch = ['7547-122', 'MHY00007']
for i in ItemsToSearch:
print('')
print('The top levels of ' + i + ' are: ')
print(BOM.find_top_levels(i))
注意self.find_top_levels(parent)的递归调用.
这将给出输出
The top levels of 7547-122 are:
['2105-0001']
The top levels of MHY00007 are:
['2094-00003', '7932-00001', '7932-00002', '7932-00010']