如何在 python 的同一行上使用 for 循環打印？

Question

我正在嘗試為我的一個程序制作一個類似於視覺文件的文件。 有child_data和parent_data

我正在嘗試使 output 類似於：

parent_data
----------|child_data
           child_data
           child_data
--------------------|grandchild_data
                     grandchild_data
----------|child_data
parent_data

我的第一次嘗試是這樣的：

def visual(self, ID):
     for i in range(self.generation(ID)): # finding how many parents of the ID 
         print(----|, end='')             # there are

但這不起作用，它在同一行打印，但當我打電話給沒有父母的 ID 時，它也一直返回 NONE。 所以 output 將是： None parent_data

Answer 1

您要使用的模式是讓節點跟蹤其子節點，然后使用遞歸 function 進行打印。

它的基本思想是這樣的：

class Node():
    def __init__(self, name, children=[]):
        self.children = children
        self.name = name

    def print(self, level=0):
        print('\t'*level, self.name)
        level += 1
        for child in self.children:    
            child.print(level)

a = Node('parent', [ Node('child', [ Node('grandchild') ]) ])

a.print()

但是要獲得您想要的確切 output ，您需要執行以下操作：

class Node():
    def __init__(self, name, children=[]):
        if not isinstance(children, list):
            children = [children]

        self.children = children
        self.name = name

    def print(self, level=0, special_print=False):
        ''' Recursively print out all of the children in a nice visual way.
        level keeps track of the indentation as we go along.
        special_print prefixes the outputted line with a bunch of --- followed by a |
        This special printing happens whenever there is a change in indentation '''

        if level is 0:
            print(self.name)
        elif special_print:
            print('----------'*level + '|' + self.name)
        else:
            print('          '*level + ' ' + self.name)

        level += 1
        special_print = True
        for child in self.children:
            child.print(level, special_print)
            special_print = bool(child.children)

a = Node('parent_data', [
        Node('child_data'),
        Node('child_data'),
        Node('child_data', [
            Node('grandchild'),
            Node('grandchild')
        ]),
        Node('child_data'),
    ])

a.print()