问题描述
我是 matplotlib 的初学者.我正在尝试使用 matplotlib.pyplot 绘制数据框.问题是每次我尝试绘制它时都会出现以下错误:
ValueError: view limit minimum -35738.3640567 小于 1 并且是无效的 Matplotlib 日期值.如果您将非日期时间值传递给具有日期时间单位的轴,则通常会发生这种情况.
根据错误提示,日期时间列中好像有非日期时间值,但没有.
我尝试使用 pd.to_datetime() 并尝试将时间戳的格式更改为 pd.to_datetime(df_google['datetime'], format = '%d/%m/%Y')代码>但没有任何变化.
这是我尝试使用的代码:
将 matplotlib.pyplot 导入为 pltdf_google.plot()plt.show()
df_google 是一个包含 ['datetime','price']
列的数据框,其中一些值如下:
日期时间价格0 2018-05-15 1079.2299801 2018-05-16 1081.7700202 2018-05-17 1078.5899663 2018-05-18 1066.3599854 2018-05-21 1079.5799565 2018-05-22 1069.7299806 2018-05-23 1079.6899417 2018-05-24 1079.2399908 2018-05-25 1075.6600349 2018-05-29 1060.319946
有人可以帮我理解这种类型的错误吗?当每个值都是日期时间类型值时,为什么它说存在非日期时间值?如何绘制此数据框?
将 'datetime'
列设置为 datetime64[ns]
类型:
- 使用
im a beginner in matplotlib. Im trying to plot a dataframe using matplotlib.pyplot. The problem is that everytime I try to plot it i get the following error:
ValueError: view limit minimum -35738.3640567 is less than 1 and is an invalid Matplotlib date value. This often happens if you pass a non-datetime value to an axis that has datetime units.
According to the error, it seems to be like theres a non-datetime value in the datetime column, but there isnt.
Ive tried using pd.to_datetime() and try to change the format of the timestamp to
pd.to_datetime(df_google['datetime'], format = '%d/%m/%Y')
but nothing changes.This is the code im trying to use:
import matplotlib.pyplot as plt df_google.plot() plt.show()
df_google is a dataframe with columns
['datetime','price']
and some of the values are the following:datetime price 0 2018-05-15 1079.229980 1 2018-05-16 1081.770020 2 2018-05-17 1078.589966 3 2018-05-18 1066.359985 4 2018-05-21 1079.579956 5 2018-05-22 1069.729980 6 2018-05-23 1079.689941 7 2018-05-24 1079.239990 8 2018-05-25 1075.660034 9 2018-05-29 1060.319946
Can someone try to help me understand this type of error? Why does it says theres a non-datetime value when every value is a datetime type value? How can I plot this dataframe?
解决方案Set the
'datetime'
column to adatetime64[ns]
type:- Use
pandas.to_datetime
to convert the'datetime'
column, and remember to assign the column back to itself, because this is not an inplace update. - Column names can be accessed with a
.
, if they do not contain special characters and do not clash with built-in attributes/methods (e.g.,index
,count
).df_google.datetime
instead ofdf_google['datetime']
import pandas as pd import matplotlib.pyplot as plt # given the following data data = {'datetime': ['2018-05-15', '2018-05-16', '2018-05-17', '2018-05-18', '2018-05-21', '2018-05-22', '2018-05-23', '2018-05-24', '2018-05-25', '2018-05-29'], 'price': [1079.22998, 1081.77002, 1078.589966, 1066.359985, 1079.579956, 1069.72998, 1079.689941, 1079.23999, 1075.660034, 1060.319946]} df_google = pd.DataFrame(data) # convert the datetime column to a datetime type and assign it back to the column df_google.datetime = pd.to_datetime(df_google.datetime) # display(df_google.head()) datetime price 0 2018-05-15 1079.229980 1 2018-05-16 1081.770020 2 2018-05-17 1078.589966 3 2018-05-18 1066.359985 4 2018-05-21 1079.579956 5 2018-05-22 1069.729980 6 2018-05-23 1079.689941 7 2018-05-24 1079.239990 8 2018-05-25 1075.660034 9 2018-05-29 1060.319946
Verify the
'datetime'
column is adatetime64[ns]
Dtype:print(df_google.info()) <class 'pandas.core.frame.DataFrame'> RangeIndex: 10 entries, 0 to 9 Data columns (total 2 columns): # Column Non-Null Count Dtype --- ------ -------------- ----- 0 datetime 10 non-null datetime64[ns] 1 price 10 non-null float64 dtypes: datetime64[ns](1), float64(1) memory usage: 288.0 bytes
Plot:
df_google.plot(x='datetime') plt.show()
- There's a substantial ecosystem of alternative plotting tools, but
df.plot()
is fine for getting a look at the data.
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- Use