Question

我正在尝试使用matplotlib创建元素频率条形图。为了实现这一点，我需要能够计算pandas dataframe列中相对于标志列表的出现次数。下面将给出我笔记本/数据中代码的粗略草图：

   # list of filtered values 
   filtered = [200, 201, 201, 201, 201, 201, 
   211, 211, 211, 211, 211, 211, 211, 211, 211, 211, 211, 211, 211, 211, 
   237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 
   237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 
   237, 237, 237, 237, 237, 237, 237, 237, 250, 250, 250, 250, 250, 250, 250,
   250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 
   250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250,
   250, 250, 250, 250, 254]

   # list of flags to use for filtering 
   flags = [200, 201, 211, 237, 239, 250, 254, 255]
   # this was just a line to code for testing
   flags_dict = {200:0,201:0,211:0,237:0,239:0,250:0,254:0,255:0}

   freq = filtered.value_counts()


   """
   Expected flags_dict:
   200: 1
   201: 5
   211: 14
   237: 38
   239: 0
   250: 40
   254: 1
   255: 0
   """

   """
   These are the values from the real dataframe but they do not take into 
   account the other flags in the flags list
   freq: 
   250.0    7682
   211.0    3734
   200.0    1483
   239.0     180
   201.0      34       
   """

Answer 1

使用isin

可以非常简单地回答这个问题

假设filtered是一个系列。

In [1]: filtered[filtered.isin(flags)].value_counts().reindex(flags, fill_value=0)
Out[1]: 200     1
        201     5
        211    14
        237    38
        239     0
        250    41
        254     1
        255     0
        dtype: int64

要获取字典，只需添加to_dict

In [2]: filtered[filtered.isin(flags)].value_counts().reindex(flags, fill_value=0).to_dict()

Out[2]: {200: 1, 201: 5, 211: 14, 237: 38, 239: 0, 250: 41, 254: 1, 255: 0}

Answer 2

我刚才想出了这个，但必须有一个更好/更快的方法来完成这个

.Range("I1").Value = iVal = Application.WorksheetFunction.CountIf(Range("A3:A103"), "CrisisNameTextBox1.Value")

Answer 3

如果我理解正确，这就是你需要的：

import pandas as pd

filtered = [200, 201, 201, 201, 201, 201, 211, 211, 211, 211, 211, 211, 211, 211, 211,
            211, 211, 211, 211, 211, 
            237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 
            237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 237, 
            237, 237, 237, 237, 237, 237, 237, 237, 250, 250, 250, 250, 250, 250, 250,
            250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 
            250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250, 250,
            250, 250, 250, 250, 254]


filtered = pd.Series(filtered)

freq = filtered.value_counts(sort=False)
flags = [200, 201, 211, 237, 239, 250, 254, 255]
flags_dict = {}
for flag in flags:
    try:
        flags_dict[flag] = freq[flag]
    except:
        flags_dict[flag] = 0

计算pandas数据帧中相对于列表的出现次数

3 个答案: