Python:从父子关系计算路径 [英] Python: Calculating the Path from Parent Child Relationships

问题描述

父)作为 csv(700,000 行)输入

Parent) as csv (700,000 rows) input

Child   Parent
fA00    f0
fA9 fA0
fA31    fA0
fA30    fA0
fA1 fA00
dccfA1  fA00
fA2 fA00
fA3 fA00
fA01    fA00
fA4 fA00
fA5 fA00
fA6 fA00
fA7 fA00
fA0 fA00
fA142149    fA00
fA02    fA00
fA8 fA00
qA1 fA10
fA22    fA10
fA23    fA10
fA11    fA10
qA2     fA10
fA15    fA11
fA13    fA11
fA12    fA11
fA14    fA13
fA17    fA16
fA18    fA17
fA19    fA17
fA20    fA17
fA21    fA19
etc....

它可以达到 14 级深度.顶级父级是 f0

It goes up to 14 levels deep. The top parent is f0

我想遍历子父关系来确定路径

I want to iterate through the child parent relationships to determine the path

预期结果

f0 --- top
f0\fa00
f0\fa00\.Child
f0\fa00\.Child2etc
f0\fA0
f0\fA0\.Child
f0\fA0\.Child2etc

如何在 Python 中执行此操作?

How can I do this in Python?

推荐答案

我开始思考 树结构 但基本上它很简单.创建子级到父级的映射，然后从子级开始，列出其父级，然后是父级的父级，直到顶部.递归程序可以轻松提取孩子的祖先.

I started out thinking complicated recursive construction of tree structures but basically it is very simple. Create a mapping of child to parent then starting at a child list its parent then the parent's parent up to the top. A recursive routine extracts the child's ancestry easily.

'''
This is the family tree:
------------------------
f0:
    a0:
        b0
        b1:
        b2:
    a1:
        b3:
        b4:
    a2:
        b5:
            c0
            c1
'''
ancestry = [
    ('b1', 'a0'),
    ('c1', 'b5'),
    ('b2', 'a0'),
    ('b3', 'a1'),
    ('b4', 'a1'),
    ('b5', 'a2'),
    ('a0', 'f0'),
    ('a1', 'f0'),
    ('a2', 'f0'),
    ('b0', 'a0'),
    ('c0', 'b5'),
]

代码是:

parents = set()
children = {}
for c,p in ancestry:
    parents.add(p)
    children[c] = p

# recursively determine parents until child has no parent
def ancestors(p):
    return (ancestors(children[p]) if p in children else []) + [p]

# for each child that has no children print the geneology
for k in (set(children.keys()) - parents):
    print '/'.join(ancestors(k))

输出为:

f0/a1/b4
f0/a0/b0
f0/a0/b1
f0/a0/b2
f0/a1/b3
f0/a2/b5/c1
f0/a2/b5/c0

我将把它作为练习阅读 csv 文件，也许可以更好地对输出进行排序.

I'll leave it as an exercise to read the csv file, and maybe sort the outputs better.

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