Plotting Date with Matplotlib and Pandas

Question

I am trying to plot number of sales on Y axis against the dates on the X axis. I can't seem to work out a way to do the dates on the X axis. If i change the dates to a float, it I can plot it but I still cannot figure out a way to plot the date format.

import matplotlib.pyplot as plt
import csv

x = []
y = []

with open('book1.csv','r') as csvfile:
    plots = csv.reader(csvfile, delimiter=',')
    for row in plots:
        x.append(float(row[0]))
        y.append(float(row[1]))

plt.plot(x,y, label='Loaded from file!')
plt.xlabel('x')
plt.ylabel('y')
plt.title('Interesting Graph\nCheck it out')
plt.legend()
plt.show()

My csv looks something like:

1/1/2019,7980.185714
2/1/2019,9478.297619
3/1/2019,9282.166667
4/1/2019,6900.833333
5/1/2019,5563.716667

If I change the dates to a float format, I get this graph:

Bal Krishna Jha · Accepted Answer · 2019-02-12 07:10:46Z

1

You need change the type of x to datetime :

import matplotlib.pyplot as plt
import csv
import datetime as dt

x = []
y = []
with open('book1.csv','r') as csvfile:
  plots = csv.reader(csvfile, delimiter=',')
  for row in plots:
      x.append(dt.datetime.strptime(row[0],'%m/%d/%Y').date())
      y.append(float(row[1]))
plt.plot(x,y, label='Loaded from file!')
plt.xlabel('x')
plt.xticks(x, x, rotation=90)
plt.ylabel('y')
plt.title('Interesting Graph\nCheck it out')
plt.legend()
plt.show()

edited Feb 12, 2019 at 7:10

answered Feb 12, 2019 at 5:39

Bal Krishna Jha

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1 Comment

FatimahFatCakes Over a year ago

Thank you!. How would I change the date labels interval to daily? Because right now its labeling the date every 4 days.

ListenSoftware Louise Ai Agent · Accepted Answer · 2021-07-27 15:39:08Z

0

sales are declining. Set the date as an index then plot the Sales

txt="""1/1/2019,7980.185714
2/1/2019,9478.297619
3/1/2019,9282.166667
4/1/2019,6900.833333
5/1/2019,5563.716667"""

from io import StringIO
f = StringIO(txt)
df = pd.read_table(f,sep =',')
df.columns=['Date','Sales']
df['Date']=pd.to_datetime(df['Date'])
df.set_index('Date',inplace=True)
plt.title("Sales")
plt.plot(df)
plt.xticks(rotation=90)
plt.show()

answered Jul 27, 2021 at 15:39

ListenSoftware Louise Ai Agent

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