graph with multiple lines python dataframe

Question

I have a dataframe where I want to create a line graph. I want 1 line per category and on the x axis I want the date, on y the 12MKG. I dont know how to put labels on the lines and make the lines different colours per categorie.

So far I have tried:

plt.plot(df['date'],datatoplot['12MKG'])

date	categorie	12MKG
202001	cat1	0.9836956
202002	cat1	0.9836956
202003	cat1	0.9831461
202004	cat1	0.97206706
202005	cat1	0.9698492
202006	cat1	0.97630334
202007	cat1	0.9787234
202008	cat1	0.9810606
202009	cat1	0.9825784
202010	cat1	0.98165137
202011	cat1	0.9768116
202012	cat1	0.96666664
202101	cat1	0.9655172
202102	cat1	0.95214105
202103	cat1	0.93721974
202104	cat1	0.9419087
202105	cat1	0.93158954
202106	cat1	0.9189189
202107	cat1	0.9144603
202001	cat2	0.3118644
202002	cat2	0.3006993
202003	cat2	0.3017544
202004	cat2	0.29433963
202005	cat2	0.3030303
202006	cat2	0.30483273
202007	cat2	0.33206108
202008	cat2	0.33730158
202009	cat2	0.344
202010	cat2	0.34008098
202011	cat2	0.34051725
202012	cat2	0.3224299
202101	cat2	0.33027524
202102	cat2	0.3187773
202103	cat2	0.29338843
202104	cat2	0.28458497
202105	cat2	0.2804878
202106	cat2	0.2804878
202107	cat2	0.2631579

kind regards,

wokter

[Convert to dates](https://stackoverflow.com/questions/45215525/python-pandas-convert-yyyymm-to-datetime)? — BigBen, Jul 26 '21 at 14:38

score 0 · Answer 1 · answered Jul 27 '21 at 19:34

Assuming I have understood your question correct there are many ways of doing this. One way is to cycle through each category and adding each line with a predetermined color. You can skip the color dict part if you want to use the default colormap. It is even possible to use colormaps to get a specific color 'theme'.

#If you want to control the color
color_dict = {'cat1': 'r',
              'cat2': 'b'}


fig, ax = plt.subplots(1,1)

# Cycle over the categories
for cat in df['categorie'].unique():
    # get the data for the relevant category
    temp = df[df['categorie']==cat]
    # plot the line using the 'label' keyword to add a label and 'color'
    # to control the color 
    ax.plot(temp['date'], temp['12MKG'], label=cat, color=color_dict[cat])

ax.legend()

graph with multiple lines python dataframe

1 Answers1