My Plot chart is not working as i expected-CodePudding

Here is the result. As you can see the order is 1,2,4,3 it should be 1,2,3,4. Here how i render it

import csv

import matplotlib.pyplot as plt

time = []
total = []
  
with open('new.csv','r') as csvfile:
    plots = csv.reader(csvfile, delimiter = ',')
      
    for row in plots:
        time.append(row[0])
        total.append(row[1])
  
plt.plot(time, total)
plt.xlabel('Dates')
plt.ylabel('Transactions')
plt.show()

and here is my csv

2022-08-25,1
2022-08-26,2
2022-08-27,4
2022-08-29,3

How can i fix it ? thanks in advance

CodePudding user response：

The problem with your code is that the y-values are strings. This simple casting to float would fix that:

import matplotlib.pyplot as plt
import csv

time = []
total = []

with open('new.csv','r') as csvfile:
    plots = csv.reader(csvfile, delimiter = ',')

    for row in plots:
        time.append(row[0])
        total.append(float(row[1]))

plt.plot(time, total)
plt.xlabel('Dates')
plt.ylabel('Transactions')
plt.show()

But notice there is also the same problem with dates, last two dates are not one day from each other but twice as much. Matplotlib know how to handle datetimes though:

import csv
from datetime import datetime as dt

import matplotlib.pyplot as plt
import matplotlib.dates as mdates

time = []
total = []

with open('new.csv','r') as csvfile:
    plots = csv.reader(csvfile, delimiter = ',')

    for row in plots:
        time.append(dt.strptime(row[0], "%Y-%m-%d"))
        total.append(float(row[1]))

plt.plot(time, total)
plt.xlabel('Dates')
plt.ylabel('Transactions')

plt.gca().xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d %H:%M:%S'))
plt.gcf().autofmt_xdate()

plt.show()

Little help taken from: Format of datetime in pyplot axis