CODEWITHSUNDEEP
matplotlib
Wizuriel
Wizuriel

Reputation: 3747

Matplotlib not using dates from data

Still pretty new to data visulization and trying to do a simple graph to monitor my weight lose attempt. Matplotlib though seems to be doing something weird when plotting the dates and not sure how to specify for the graph to use my dates instead of trying to always start at the start of the month

import pandas as pd
import numpy as np
dfOrg = pd.DataFrame({"Date": ["2019-1-7", "2019-1-14", "2019-1-21","2019-1-28","2019-2-4","2019-2-11",
                          "2019-2-18", "2019-2-25", "2019-3-4"],
              "Weight:": [204.3,201,202.5,200.7,201.5,202.5,199.5,200.8,201.5]})
dfOrg["Date"] = pd.to_datetime(dfOrg['Date'])
maxDT = dfOrg["Date"].max()
missing = {}
missing["Date"] = pd.date_range(start=maxDT, end='2019-10-07', freq='7D',closed="right")
missing["Weight"] = []
for i in missing["Date"]:
    missing["Weight"].append(np.NaN)
missingDF = pd.DataFrame(missing)
df = pd.concat([dfOrg, missingDF], ignore_index=True)
df.drop(["Weight"], axis=1, inplace=True)
df.rename(columns={"Weight:": "Weight"}, inplace=True)


import matplotlib.pyplot as plt
import matplotlib.dates as dates
import datetime

formatter = dates.DateFormatter('%b %d') 
plt.plot(df["Date"], df["Weight"], color="g")
plt.xticks(rotation=70)
plt.ylabel("LBS")
plt.title("Weight Loss Progress")
plt.axhline(linewidth=4, color='gold', y=170, label="Goal")
plt.ylim(160, 210)
plt.legend(bbox_to_anchor=[1, 0.5], loc='center left')
plt.gcf().axes[0].xaxis.set_major_formatter(formatter)
plt.show()

So ideally the graph should be showing my weight where the dates go from 2019-1-7 to 2019-10-07 which is my goal and a goal line. Instead when I see the graph it shows

enter image description here

Upvotes: 1

Views: 40

Answers (1)

Ghost
Ghost

Reputation: 248

You can use 

plt.xlim([plt.xlim()[0], datetime.date(2019, 10, 7)])

to adjust the x-axis range. This will give you

Code output

Edit - You can set the ticks to one per week on a specified weekday using

plt.gca().xaxis.set_major_locator(dates.WeekdayLocator(byweekday=dates.MO))

Which will give you By Weekday

Upvotes: 1

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