ナンシーアレイは同じ形状ですが、ValueErrorを取得しています：xとyの最初の次元は同じでなければなりません

Question

Stumped。

おかげ

import matplotlib.pyplot as plt 
import numpy as np 
from datetime import datetime 

num_of_days = 31 
dates = np.empty(num_of_days) 
ranks = np.empty(dates.shape[0]) 
ranks.fill(50) # test data all 50's 
dates = np.arange('2016-01', num_of_days , dtype='datetime64[D]') 
print("ranks shape", ranks.shape) 
print("dates shape", dates.shape) 
print("ranks type", type(ranks)) 
print("dates type", type(dates)) 
print("dates shape first dimension",dates.shape[0]) 
print(dates) 
print(ranks) 

plt.plot_date(dates,2) 
plt.plot(dates,ranks) 
plt.show() 

コードの実行利回り

Python 3.5.1 (v3.5.1:37a07cee5969, Dec 6 2015, 01:38:48) [MSC v.1900 32 bit (Intel)] on win32 
Type "copyright", "credits" or "license()" for more information. 
>>> 
===== RESTART: E:\scanned\als course\12 15 14 the al project\dev code\8 29 16 test plots.py ===== 
ranks shape (31,) 
dates shape (31,) 
ranks type <class 'numpy.ndarray'> 
dates type <class 'numpy.ndarray'> 
dates shape first dimension 31 
['2016-01-01' '2016-01-02' '2016-01-03' '2016-01-04' '2016-01-05' 
'2016-01-06' '2016-01-07' '2016-01-08' '2016-01-09' '2016-01-10' 
'2016-01-11' '2016-01-12' '2016-01-13' '2016-01-14' '2016-01-15' 
'2016-01-16' '2016-01-17' '2016-01-18' '2016-01-19' '2016-01-20' 
'2016-01-21' '2016-01-22' '2016-01-23' '2016-01-24' '2016-01-25' 
'2016-01-26' '2016-01-27' '2016-01-28' '2016-01-29' '2016-01-30' 
'2016-01-31'] 
[ 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 
    50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 
    50.] 
Traceback (most recent call last): 
    File "E:\scanned\als course\12 15 14 the al project\dev code\8 29 16 test plots.py", line 23, in <module> 
    plt.plot_date(dates,2) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\pyplot.py", line 3173, in plot_date 
    data=data, **kwargs) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\__init__.py", line 1812, in inner 
    return func(ax, *args, **kwargs) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\axes\_axes.py", line 1494, in plot_date 
    ret = self.plot(x, y, fmt, **kwargs) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\__init__.py", line 1812, in inner 
    return func(ax, *args, **kwargs) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\axes\_axes.py", line 1424, in plot 
    for line in self._get_lines(*args, **kwargs): 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\axes\_base.py", line 386, in _grab_next_args 
    for seg in self._plot_args(remaining, kwargs): 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\axes\_base.py", line 364, in _plot_args 
    x, y = self._xy_from_xy(x, y) 
    File "C:\Users\dave\AppData\Local\Programs\Python\Python35-32\lib\site-packages\matplotlib\axes\_base.py", line 223, in _xy_from_xy 
    raise ValueError("x and y must have same first dimension") 
ValueError: x and y must have same first dimension 
>>> 

Answer 1

：「xとyが同じ最初の次元を持たなければならないとValueError」彼らは両方なぜ私が取得しています同じ形状です両方numpyの配列です。ドキュメントから

：

plot_date(x, y, fmt='bo', tz=None, xdate=True, 
      ydate=False, **kwargs) 
Similar to the plot() command, except the x or y (or both) data is considered to be dates, and the axis is labeled accordingly. 

あなたdatesは（31）であるが、何でです2？なぜ31の値を持つ配列ではないのですか？

plt.plot_date(dates, np.arange(dates.shape[0])) 

x軸上の日付を含む立上りラインのポイントのセットをプロットします。