按类别对观测值进行排序

Question

我有下面的代码，它生成一个Seaborn条带图，然后在每个类别下写下观察值的数量。但如果在stripplot（）调用中指定不同的类别顺序，则数字的顺序不正确

我需要帮助找出一种方法来排序我的nobs系列，使数字匹配的顺序，类别在猫的顺序。有什么优雅的方法吗

# import libraries
import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

# create some fake data

df = pd.DataFrame(data=None,columns=['Fuel','MW'])
df = df.astype(dtype={'Fuel':'category', 'MW':'float'})
rnd = np.random.RandomState(1)
mymean = 4 # starting mean value for use in the distribution below
mysigma = 0.8 # sigma value for use in the distribution below
myfuels = ['Bio','Coal','Hydro','Gas','Oil','Other','Solar','Wind'] # categories
mysize = 10 
for myfuel in myfuels:
    myMWs = list(rnd.lognormal(mean=mymean,sigma=mysigma,size=mysize)) # random generated data
    newdata = pd.DataFrame({'Fuel': [myfuel]*mysize,
                           'MW':  myMWs})
    df = df.append(newdata,
                   ignore_index=True
                  )    
    mymean = mymean + 0.4 # increment to have different distributions
    mysize = mysize + 3

# see distribution of created data

# Set up figure and axes
fig1, ax1 = plt.subplots(nrows=1, ncols=1, figsize=(14,5))

sns.set_style('darkgrid')

# define category order (same as myfuels, except Other is at end)
cat_order = ['Bio','Coal','Hydro','Gas','Oil','Solar','Wind','Other']

sns.stripplot(x = 'Fuel',
               y = 'MW',
               data=df,
               order=cat_order,
               jitter=0.35,
               size=2.5,
               ax = ax1,
               palette='dark'
              )   

ax1.set_ylim([-400,5500])

# add tags for number of observations in each category
nobs = df.groupby(['Fuel'])['MW'].agg(['count'])['count'] #Is there a more elegant form of this line?
myv = -280 # get this value through inspection and trial and error
myh = 0 # first category is always at horiz position = 0
for item in nobs:
    if myh == 0:
        plt.text(myh, myv, 'n = ' + str(item), ha='center', fontsize=9)
    else:
        plt.text(myh, myv, item, ha='center', fontsize=9)
    myh = myh + 1 # move one unit to the right for each category

plt.show()

这是电流输出（不正确地显示了观察次数）

Answer 1

您希望按照用于打印stripplot的类别顺序重新索引nobs系列

nobs = df.groupby(['Fuel'])['MW'].agg(['count'])['count'].reindex(cat_order)