打印带有标题的表时可以替代locals() [英] Alternative to locals() in printing a table with a header

问题描述

[Python 3.1]

原始代码有误.

我需要打印一张桌子.第一行应该是标题，其中包含由制表符分隔的列名称.以下各行应包含数据(也用制表符分隔).

I need to print a table. The first row should be a header, which consists of column names separated by tabs. The following rows should contain the data (also tab-separated).

为澄清起见，假设我有速度"，功率"，重量"列.我最初是在我之前问过的相关问题的帮助下编写的以下代码:

To clarify, let's say I have columns "speed", "power", "weight". I originally wrote the following code, with the help from a related question I asked earlier:

column_names = ['speed', 'power', 'weight']

def f(row_number):
  # some calculations here to populate variables speed, power, weight
  # e.g., power = retrieve_avg_power(row_number) * 2.5
  # e.g., speed = math.sqrt(power) / 2
  # etc.
  locals_ = locals()
  return {x : locals_[x] for x in column_names}

def print_table(rows):
  print(*column_names, sep = '\t')
  for row_number in range(rows):
    row = f(row_number)
    print(*[row[x] for x in component_names], sep = '\t')

但是后来我了解到，如果可能，我应该避免使用locals() .

But then I learned that I should avoid using locals() if possible.

现在，我被卡住了.我不想多次键入所有列名称的列表.我不想依赖这样的事实，即我在f()中创建的每个字典都可能以相同的顺序遍历其键.而且我不想使用locals().

Now I'm stuck. I don't want to type the list of all the column names more than once. I don't want to rely on the fact that every dictionary I create inside f() is likely to iterate through its keys in the same order. And I don't want to use locals().

请注意，函数print_table()和f()还有很多其他功能；所以我必须将它们分开.

Note that the functions print_table() and f() do a lot of other stuff; so I have to keep them separate.

我应该如何编写代码?

推荐答案

class Columns:
    pass

def f(row_number):
    c = Columns()
    c.power = retrieve_avg_power(row_number) * 2.5
    c.speed = math.sqrt(power) / 2
    return c.__dict__

这也使您可以指定哪些变量是列，而不是在函数中是临时变量.

This also lets you specify which of the variables are meant as columns, instead of rather being temporary in the function.

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