Im trying to plot date in x-axis, sales volume in primary y-axis and price in secondary y-axis. Since x-axis is a date type, I have used plt.plot_date() function from matplotlib.
I tried secondary_y = True which throws
AttributeError: 'Line2D' object has no property 'secondary_y'
Is it possible to add secondary y-axis with plt.plot_date() or any better way to do this?
Code as below:
plt.plot_date(x = df['Date'], y = df['Sales_Volume'], fmt = '-')
plt.plot_date(x = df['Date'], y = df['Price'], fmt = '-', secondary_y = True)
plt.xticks(rotation = 90)
plt.show()
Please note: sales volume and price has different ranges
you need to use twinx() to add a secondary axis to your plot. I have created a simple example to show the same. I have added a few options so that you can see how to add color, legend, etc. Use the ones you want/like.
import pandas as pd
import numpy as np
from datetime import datetime, timedelta
import matplotlib.dates as mdates
from matplotlib.dates import AutoDateFormatter, AutoDateLocator
date_today = datetime.now()
days = pd.date_range(date_today, date_today + timedelta(20), freq='D')
np.random.seed(seed=1111)
df = pd.DataFrame({'date': days}) # Your date field
df = df.set_index('date')
fig,ax1 = plt.subplots(figsize=(12,5))
l1, = ax1.plot(df.index,np.random.rand(len(df),1)*100, marker = "o", color='green') #Your Price field
ax1.set_ylabel('Price (y1 axis)')
ax2 = ax1.twinx() ##Using twinx to make ax2 as secondary axis for ax1
l2, = ax2.plot(df.index,np.random.rand(len(df),1)*800,marker = "o", color='red') #Your sales field
ax2.set_ylabel('Sales-volume (y2 axis)')
fig.legend([l1, l2], ["Price", "Sales Volume"])
xtick_locator = AutoDateLocator()
xtick_formatter = AutoDateFormatter(xtick_locator)
ax1.xaxis.set_major_locator(xtick_locator)
ax1.xaxis.set_major_formatter(xtick_formatter)
Related
Data I'm working with: https://drive.google.com/file/d/1xb7icmocz-SD2Rkq4ykTZowxW0uFFhBl/view?usp=sharing
Hey everyone,
I am a bit stuck with editing a plot.
Basically, I would like my x value to display the months in the year, but it doesn't seem to work because of the data type (?). Do you have any idea how I could get my plot to have months in the x axis?
If you need more context about the data, please let me know!!!
Thank you!
Here's my code for the plot and the initial data modifications:
import matplotlib.pyplot as plt
import mplleaflet
import pandas as pd
import matplotlib.dates as mdates
from matplotlib.dates import DateFormatter
import numpy as np
df = pd.read_csv("data/C2A2_data/BinnedCsvs_d400/fb441e62df2d58994928907a91895ec62c2c42e6cd075c2700843b89.csv")
df['degrees']=df['Data_Value']/10
df['Date'] = pd.to_datetime(df['Date'])
df2 = df[df['Date']<'2015-01-01']
df3 = df[df['Date']>='2015-01-01']
max_temp = df2.groupby([(df2.Date.dt.month),(df2.Date.dt.day)])['degrees'].max()
min_temp = df2.groupby([(df2.Date.dt.month),(df2.Date.dt.day)])['degrees'].min()
max_temp2 = df3.groupby([(df3.Date.dt.month),(df3.Date.dt.day)])['degrees'].max()
min_temp2 = df3.groupby([(df3.Date.dt.month),(df3.Date.dt.day)])['degrees'].min()
max_temp.plot(x ='Date', y='degrees', kind = 'line')
min_temp.plot(x ='Date',y='degrees', kind= 'line')
plt.fill_between(range(len(min_temp)),min_temp, max_temp, color='C0', alpha=0.2)
ax = plt.gca()
ax.set(xlabel="Date",
ylabel="Temperature",
title="Extreme Weather in 2015")
plt.legend()
plt.tight_layout()
x = plt.gca().xaxis
for item in x.get_ticklabels():
item.set_rotation(45)
plt.show()
Plot I'm getting:
Option 1 (Most Similar Approach)
Change the index based on month abbreviations using Index.map and calendar
This is just for df2:
import calendar
import matplotlib.pyplot as plt
import pandas as pd
df = pd.read_csv("...")
df['degrees'] = df['Data_Value'] / 10
df['Date'] = pd.to_datetime(df['Date'])
df2 = df[df['Date'] < '2015-01-01']
max_temp = df2.groupby([df2.Date.dt.month, df2.Date.dt.day])['degrees'].max()
min_temp = df2.groupby([df2.Date.dt.month, df2.Date.dt.day])['degrees'].min()
# Update the index to be the desired display format for x-axis
max_temp.index = max_temp.index.map(lambda x: f'{calendar.month_abbr[x[0]]}')
min_temp.index = min_temp.index.map(lambda x: f'{calendar.month_abbr[x[0]]}')
max_temp.plot(x='Date', y='degrees', kind='line')
min_temp.plot(x='Date', y='degrees', kind='line')
plt.fill_between(range(len(min_temp)), min_temp, max_temp,
color='C0', alpha=0.2)
ax = plt.gca()
ax.set(xlabel="Date", ylabel="Temperature", title="Extreme Weather 2005-2014")
x = plt.gca().xaxis
for item in x.get_ticklabels():
item.set_rotation(45)
plt.margins(x=0)
plt.legend()
plt.tight_layout()
plt.show()
As an aside: the title "Extreme Weather in 2015" is incorrect because this data includes all years before 2015. This is "Extreme Weather 2005-2014"
The year range can be checked with min and max as well:
print(df2.Date.dt.year.min(), '-', df2.Date.dt.year.max())
# 2005 - 2014
The title could be programmatically generated with:
title=f"Extreme Weather {df2.Date.dt.year.min()}-{df2.Date.dt.year.max()}"
Option 2 (Simplifying groupby step)
Simplify the code using groupby aggregate to create a single DataFrame then convert the index in the same way as above:
import calendar
import matplotlib.pyplot as plt
import pandas as pd
df = pd.read_csv("...")
df['degrees'] = df['Data_Value'] / 10
df['Date'] = pd.to_datetime(df['Date'])
df2 = df[df['Date'] < '2015-01-01']
# Get Max and Min Degrees in Single Groupby
df2_temp = (
df2.groupby([df2.Date.dt.month, df2.Date.dt.day])['degrees']
.agg(['max', 'min'])
)
# Convert Index to whatever display format is desired:
df2_temp.index = df2_temp.index.map(lambda x: f'{calendar.month_abbr[x[0]]}')
# Plot
ax = df2_temp.plot(
kind='line', rot=45,
xlabel="Date", ylabel="Temperature",
title=f"Extreme Weather {df2.Date.dt.year.min()}-{df2.Date.dt.year.max()}"
)
# Fill between
plt.fill_between(range(len(df2_temp)), df2_temp['min'], df2_temp['max'],
color='C0', alpha=0.2)
plt.margins(x=0)
plt.tight_layout()
plt.show()
Option 3 (Best overall functionality)
Convert the index to a datetime using pd.to_datetime. Choose any leap year to uniform the data (it must be a leap year so Feb-29 does not raise an error). Then set the set_major_formatter using the format string %b to use the month abbreviation:
import matplotlib.dates as mdates
import matplotlib.pyplot as plt
import pandas as pd
df = pd.read_csv("...")
df['degrees'] = df['Data_Value'] / 10
df['Date'] = pd.to_datetime(df['Date'])
df2 = df[df['Date'] < '2015-01-01']
# Get Max and Min Degrees in Single Groupby
df2_temp = (
df2.groupby([df2.Date.dt.month, df2.Date.dt.day])['degrees']
.agg(['max', 'min'])
)
# Convert to DateTime of Same Year
# (Must be a leap year so Feb-29 doesn't raise an error)
df2_temp.index = pd.to_datetime(
'2000-' + df2_temp.index.map(lambda s: '-'.join(map(str, s)))
)
# Plot
ax = df2_temp.plot(
kind='line', rot=45,
xlabel="Date", ylabel="Temperature",
title=f"Extreme Weather {df2.Date.dt.year.min()}-{df2.Date.dt.year.max()}"
)
# Fill between
plt.fill_between(df2_temp.index, df2_temp['min'], df2_temp['max'],
color='C0', alpha=0.2)
# Set xaxis formatter to month abbr with the %b format string
ax.xaxis.set_major_formatter(mdates.DateFormatter('%b'))
plt.tight_layout()
plt.show()
The benefit of this approach is that the index is a datetime and therefore will format better than the string representations of options 1 and 2.
i have x-axis which is in terms of days (366 days Feb was taken as 29 days) but instead I want to convert it in terms of months (Jan - Dec). What should i do...
def plotGraph():
line, point = getXY()
plt.plot(line['xlMax'], c='orangered', alpha=0.5, label = 'Minimum Temperature (2005-14)')
plt.plot(line['xlMin'], c='dodgerblue', alpha=0.5, label = 'Minimum Temperature (2005-14)')
plt.scatter(point['xsMax'].index, point['xsMax'], s = 10, c = 'maroon', label = 'Record Break Minimum (2015)')
plt.scatter(point['xsMin'].index, point['xsMin'], s = 10, c = 'midnightblue', label = 'Record Break Maximum (2015)')
ax1 = plt.gca() # Primary axes
ax1.fill_between(line['xlMax'].index , line['xlMax'], line['xlMin'], facecolor='lightgray', alpha=0.25)
ax1.grid(True, alpha = 1)
for spine in ax1.spines:
ax1.spines[spine].set_visible(False)
ax1.spines['bottom'].set_visible(True)
ax1.spines['bottom'].set_alpha(0.3)
# Removing Ticks
ax1.tick_params(axis=u'both', which=u'both',length=0)
plt.show()
I think the quickest change might be to just set new ticks and tick labels at the starts of months; I found the conversion from day-of-the-year to month here, the first table:
import numpy as np
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
x = range(1,367)
y = np.random.rand(len(range(1,367)))
ax.plot(x,y)
month_starts = [1,32,61,92,122,153,183,214,245,275,306,336]
month_names = ['Jan','Feb','Mar','Apr','May','Jun',
'Jul','Aug','Sep','Oct','Nov','Dec']
ax.set_xticks(month_starts)
ax.set_xticklabels(month_names)
Note I assumed your days were numbered 1 to 366; if they are 0 to 365 you may have to change the range.
But I think usually a better approach is to get your days into some sort of datetime; this is more flexible and usually pretty smart. If say, your days were not confined to one year, it would be more complicated to associate day numbers with months.
This example uses datetime instead of integers. The dates are plotted on the x-axis directly, and then the DateFormatter and MonthLocator from matplotlib.dates are used to format the axis appropriately:
import datetime as dt
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
import numpy as np
start = dt.datetime(2016,1,1) #there has to be a year given, even if it isn't plotted
new_dates = [start + dt.timedelta(days=i) for i in range(366)]
fig, ax = plt.subplots()
x = new_dates
y = np.random.rand(len(range(1,367)))
xfmt = mdates.DateFormatter('%b')
months = mdates.MonthLocator()
ax.xaxis.set_major_locator(months)
ax.xaxis.set_major_formatter(xfmt)
ax.plot(x,y)
I'm learning Seaborn and trying to figure out how I can format an X axis for dates over a yearly period, so that it is readable. Let's assume we have a dataframe which holds weather measurements for each day of an entire year (365 rows).
sns.scatterplot(x = df_weather["DATE"], y = df_weather["MAX_TEMPERATURE_C"], color = 'red')
sns.scatterplot(x = df_weather["DATE"], y = df_weather["MIN_TEMPERATURE_C"], color = 'blue')
plt.show()
How can I ensure that the X axis labels are readable? Ideally, one label per month would be fine.
Thanks!
Not very sure what your column date is like, but maybe try something like below, first generate some data, I have the date as a string which I guess is something like yours:
import matplotlib.pyplot as plt
import pandas as pd
import seaborn as sns
DATE = pd.date_range('2020-01-01', periods=365, freq='D').strftime('%y%y-%m-%d')
MIN = np.random.uniform(low=10,high=25,size = len(index))
MAX = MIN + np.random.uniform(low=5,high=10,size =len(index))
df = pd.DataFrame({'DATE':DATE,'MIN':MIN,'MAX':MAX})
Plot like you did using sns:
fig, ax = plt.subplots(figsize = (10,4))
ax = sns.scatterplot(x = "DATE", y = "MAX",data=df, color = 'red')
ax = sns.scatterplot(x = "DATE", y = "MIN",data=df, color = 'blue')
Now we define the start of the mths to define ticks:
mths = pd.date_range('2020-01-01', periods=12, freq='MS')
ax.set_xticks(mths.strftime('%y%y-%m-%d'))
ax.set(xticklabels=mths.strftime('%b'))
plt.show()
And it should look ok:
I am trying to add a list of dates to Matplotlib xticks and when I do that the actual plot disappears keeping only xticks.
For example, I have the following code:
import numpy as np
import datetime as dt
import matplotlib.pyplot as plt
from matplotlib.dates import (DateFormatter, rrulewrapper, RRuleLocator, YEARLY)
# Generate random data and dates
data = np.random.randn(10000)
start = dt.datetime.strptime("2019-03-14", "%Y-%m-%d")
end = dt.datetime.strptime("2046-07-30", "%Y-%m-%d")
date = [start + dt.timedelta(days=x) for x in range(0, (end-start).days)]
rule = rrulewrapper(YEARLY, byeaster=1, interval=2)
loc = RRuleLocator(rule)
formatter = DateFormatter('%d/%m/%y')
fig, ax = plt.subplots()
ax.xaxis.set_major_locator(loc)
ax.xaxis.set_major_formatter(formatter)
ax.xaxis.set_tick_params(rotation=30, labelsize=10)
plt.plot(data)
# ax.set_xlim(min(date), max(date))
plt.show()
This code plots the data which looks like this:
Now if I uncomment ax.set_xlim(min(date), max(date)) and rerun the code I get:
You can see that I only get the dates, formatted correctly but not the plot. I am not sure what the problem here. Any help would be appreciated.
Update
If I change data = np.random.randn(10000) to data = np.random.randn(1000000), then I am able to see the plot Which is not what I want
Most likely your data is plotted, but not at the correct location. If you go along that example you would need to add something like fig.autofmt_xdate() to your code.
The way to do this is by passing the date array along with data array in the plot method. That is with the given example it will be:
import numpy as np
import datetime as dt
import matplotlib.pyplot as plt
from matplotlib.dates import (DateFormatter, rrulewrapper, RRuleLocator, YEARLY)
# Generate random data and dates
data = np.random.randn(10000)
start = dt.datetime.strptime("2019-03-14", "%Y-%m-%d")
end = dt.datetime.strptime("2046-07-30", "%Y-%m-%d")
date = [start + dt.timedelta(days=x) for x in range(0, (end-start).days)]
rule = rrulewrapper(YEARLY, byeaster=1, interval=2)
loc = RRuleLocator(rule)
formatter = DateFormatter('%d/%m/%y')
fig, ax = plt.subplots()
ax.xaxis.set_major_locator(loc)
ax.xaxis.set_major_formatter(formatter)
ax.xaxis.set_tick_params(rotation=30, labelsize=10)
plt.plot(date, data)
ax.set_xlim(min(date), max(date))
plt.show()
Then you'll get:
See matplotlib.pyplot.plot() for more information.
I wanted to plot a data which has datetime values for the x axis and another set of values as y. As an example, I will use the example from matplotlib where y in this case are stock prices. Here is the code for that.
import matplotlib.pyplot as plt
from matplotlib.finance import quotes_historical_yahoo_ochl
from matplotlib.dates import YearLocator, MonthLocator, DateFormatter
import datetime
date1 = datetime.date(1995, 1, 1)
date2 = datetime.date(2004, 4, 12)
years = YearLocator() # every year
months = MonthLocator() # every month
yearsFmt = DateFormatter('%Y')
quotes = quotes_historical_yahoo_ochl('INTC', date1, date2)
if len(quotes) == 0:
raise SystemExit
dates = [q[0] for q in quotes]
opens = [q[1] for q in quotes]
fig, ax = plt.subplots()
ax.plot_date(dates, opens, '-')
# format the ticks
ax.xaxis.set_major_locator(years)
ax.xaxis.set_major_formatter(yearsFmt)
ax.xaxis.set_minor_locator(months)
ax.autoscale_view()
# format the coords message box
def price(x):
return '$%1.2f' % x
ax.fmt_xdata = DateFormatter('%Y-%m-%d')
ax.fmt_ydata = price
ax.grid(True)
fig.autofmt_xdate()
plt.show()
Now, what I want to do is color each value in the graph based on some criterion. For simplicity's sake, let's say that the criterion in the case of the example is based on the year. That is, prices belonging to the same year will be colored the same. How would I do that? Thanks!
You can use numpy arrays with masks over the range you want (in this case a year). In order to use the inbuilt YearLocator function from your example, you need to plot the graph first and set the ticks, then remove and replace with the range per year, from your example,
import matplotlib.pyplot as plt
from matplotlib.finance import quotes_historical_yahoo_ochl
from matplotlib.dates import YearLocator, MonthLocator, DateFormatter
import datetime
import numpy
date1 = datetime.date(1995, 1, 1)
date2 = datetime.date(2004, 4, 12)
years = YearLocator() # every year
months = MonthLocator() # every month
yearsFmt = DateFormatter('%Y')
quotes = quotes_historical_yahoo_ochl('INTC', date1, date2)
if len(quotes) == 0:
raise SystemExit
dates = np.array([q[0] for q in quotes])
opens = np.array([q[1] for q in quotes])
fig, ax = plt.subplots()
l = ax.plot_date(dates, opens, '-')
# format the ticks
ax.xaxis.set_major_locator(years)
ax.xaxis.set_major_formatter(yearsFmt)
ax.xaxis.set_minor_locator(months)
ax.autoscale_view()
l[0].remove()
py = years()[0]
for year in years()[1:]:
mask = (py < dates) & (dates < year)
ax.plot_date(dates[mask], opens[mask], '-')
py = year
# format the coords message box
def price(x):
return '$%1.2f' % x
ax.fmt_xdata = DateFormatter('%Y-%m-%d')
ax.fmt_ydata = price
ax.grid(True)
fig.autofmt_xdate()
plt.show()
which gives,
The way I typically do this is by using a for loop to plot different sections of the data, coloring each section as I go. In your example, this section:
fig, ax = plt.subplots()
ax.plot_date(dates, opens, '-')
becomes:
# import the colormaps
from maplotlib import cm
fig, ax = plt.subplots()
for y in years:
y_indices = [i for i in range(len(dates)) if dates[i].year==y]
# subset the data, there are better ways to do this
sub_dates = [dates[i] for i in y_indices]
sub_opens = [opens[i] for i in y_indices]
# plot each section of data, using a colormap to change the color for
# each iteration.
ax.plot_date(sub_dates, sub_opens, '-', linecolor=cm.spring((y-2000)/10.0)