python命令字典重复键 [英] python ordered dict with duplicates keys

问题描述

我正在尝试编写一些python函数来生成一批输入文件，例如，其中包含以下代码块:

I'm trying to write some python functions to generate a batch of input files, in which there is, for instance, this block:

***behavior
**energy_phase_1
ef_v 10
**energy_phase_2
ef_v 7.

到目前为止，我正在使用collections.OrderedDict，因为顺序在这种输入文件中很重要.例如，如果我的批处理中有两个模拟:

So far i was using collections.OrderedDict, because order matters in this kind of input file). For instance,if there are two simulations in my batch:

inp_dict['***behavior'] = [ '', '']
inp_dict['**energy_phase_1'] = [ '', '']
inp_dict['**ef_v'] = [ '10', '20']
inp_dict['**energy_phase_2'] = [ '', '']
inp_dict['**ef_v'] = [ '7', '14']

要写入文件，我将做如下操作:

And to write the file I would just do something like:

for s , n in enumerate(sim_list):
    ......some code...
    inp_file.write(' '.join([ key, val[s], '\n' for key, val in inp_dict.items]))

但是，正如您所看到的，这还不够，因为字典中有重复项.

But as you can see, this is not enough, since it there are duplicates key in the dict.

所以我的问题是:是否有一个允许重复键的有序字典?例如，如果存在dict ['key'] = 1和dict ['key'] = 2，则第一个调用将返回1，第二个返回2?

So my question is: is there an ordered dict that allows for duplicate keys? For instance, if there exists dict['key']=1 and dict['key']=2, first call would return 1 and second 2?

或者，是否有一些聪明而简单的方法来实现我想要的愿望?

Or, is there some clever and simple way to achieve want I want?

谢谢

推荐答案

重复键的概念与dict的概念背道而驰.

The concept of duplicate key goes against the concept of dict.

如果您需要维护订单并且有重复的密钥，我想您需要使用其他数据结构.一种可能的解决方案是使用元组列表.类似于以下内容:

If you need to maintain order and have duplicate keys I'd say you need to use another data structure. One possible solution would be using a list of tuples. Something like the following:

inp = list()

# Define your input as a list of tuples instead of as a dict

inp.append(('***behavior', ('', '')))
inp.append(('**energy_phase_1', ('', '')))
inp.append(('**ef_v', ('10', '20')))
inp.append(('**energy_phase_2', ('', '')))
inp.append(('**ef_v', ('7', '14')))

# You can have duplicate keys on the list and the order is preserved

output = "\n".join(["{key} {val}".format(key=t[0], val=t[1][0]).strip() for t in inp])

在这种情况下，output变量将包含:

In this case the output variable would contain:

***behavior
**energy_phase_1
**ef_v 10
**energy_phase_2
**ef_v 7

如果您需要通过键访问值(类似dict的功能)，则可以使用以下方式:

If you need to access values by key (a dict-like functionality) you could use something like this:

def get_key_values(inp, key):

    filtr_by_key = filter(lambda t: True if t[0] == key else False, inp)
    return filtr_by_key

ef_v_values = get_key_values(inp, "**ef_v")

在这种情况下，ef_v_values将仅包含与键**ef_v关联的值:

In this case the ef_v_values would contain only the values associated with the key **ef_v:

[('**ef_v', ('10', '20')), ('**ef_v', ('7', '14'))]

希望这会有所帮助.

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