How to plot a Date Chart with same dates

📊 Plotly Python
1

Hi,

I want to create a time graph but the problem is that I have a csv with the same dates, but I don’t know how to graph it. I’ll keep the csv short:

Date,Quantity
2019-23-05,1
2019-23-05,4
2019-23-05,2
2019-23-05,4
2019-23-05,4
2019-23-05,4
2019-23-05,4
2019-24-05,7
2019-24-05,1
2019-23-07,1
2020-11-01,3

And my code(Updated):

import plotly.graph_objects as go
import pandas as pd

df = pd.read_csv("Publications1.csv")
dfg = df.groupby(['Date']).sum()

fig = go.Figure()
fig.add_trace(go.Scatter(
                x=dfg.index,
                y=dfg['Quantity'],
                name="Example graph",
                line_color='deepskyblue',
                opacity=0.8))

fig.update_layout(xaxis_range=['2019-03-01','2020-01-31'],
                  title_text="Data recolected")
fig.show()

1835×929

I want the amount to be shown on the graph with the sum of each month’s values. For example, 2019-23-05 has 23 quantities and this should be reflected in the graph as one point.

Thank you very much.

2

Hi @XzMn, welcome to the forum! If you’re using px.bar from plotly.express, you will get a graph with stacked bars so that the height of the bar will be the total for the date (fig = px.bar(df, x='Date', y='Quantity')). You can also plot a go.Histogram with histfunc='sum'. If you want scatter points, then you have to transform first the dataframe to compute the sum, using a groupby operation (df.groupby('Date').sum()), see https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.groupby.html and https://pandas.pydata.org/pandas-docs/stable/user_guide/groupby.html

3

Hi @XzMn,

To define a trace of type scatter, as you want, just group your data in the Dataframe, by date, i.e. define a new dataframe as follows:

dfg = df.groupby(['Date']).sum()

dfg has date as index and the column ‘Quantity’. Then define the trace by:

fig.add_trace(go.Scatter(
                x=dfg.index,
                y=dfg['Quantity'],
                name="Example graph",
                line_color='deepskyblue',
                opacity=0.8))
1 Like
4

Hi, thanks for you response. I put your code lines in my code but the graph is not displayed :frowning:

5

Hi, thanks for you response. I put your code lines in my code but the graph is not displayed :frowning:

6

Can you share the updated code?

7

Yes, I already update the code.

8

@XzMn

Here is the complete code:

import numpy as np
import plotly.graph_objs as go
import pandas as pd
from datetime import datetime

d ={'Date': [datetime(2019, 5, 23)]*7+ [datetime(2019, 5,24)]*2+ [datetime(2019, 7, 1), datetime(2020, 1, 11)],
    'Quantity' : [1, 4, 2,  4, 4, 4, 4,7,  1, 1, 3]}


df = pd.DataFrame(d)
dfg = df.groupby(['Date']).sum()




fig = go.Figure()
fig.add_trace(go.Scatter(
                x=dfg.index,
                y=dfg['Quantity'],
                name="Example graph",
                line_color='deepskyblue',
                opacity=0.8))

plot-groupby
plot-groupby700×450 8.92 KB

The dataframe dfg (after grouping by date):


         Quantity
Date	
2019-05-23	23
2019-05-24	8
2019-07-01	1
2020-01-11	3
9

Thanks! and it works! but how would it be with the CSV? Because as you did, it’s without reading the CSV data. I’d appreciate your cooperation!

10

Use df['Date'] = pd.to_datetime(df['Date'], format="%Y-%d-%m") to convert to a format understood by plotly.

11

There, that was it! I thank you very much. That worked well.