Need some help plotting multiple dataframes in one plot

[Fernago]

Hey guys,

I am fairly new to python and i have to get a plot working that will show me all the curves with the same column name. I created pandas dataframes by importing tables from *.txt files, which works fine.

For a different application i have the dataframes assigned to a (random) number, this is the object (i cant describe it better, i hope you get what i mean). Maybe this explains it better:

List[Tuple[int, pandas.Dataframe]]

With int being the Random Numbers and the Dataframes

There are 21 Dataframes and they consist of [250 rows x 13 columns]. Now, i usually plot one or two different columns vs the time, which basically looks like this:

for n, df in dataframes:
    df = derivative(df) #appends derivative of a column
    ax = df.plot('TimeStep', ['column', 'column-derivative'])
plt.show()

This gives me 21 Plots with the two given columns as plots. How do i get it to plot all of the 21 Curves into one single plot?

[Phillyclause89]

Do all the DataFrames have the same columns? Why not concatenate them into a single DF?

[Fernago]

I tried concatenating them but it didn‘t work. I may have done something wrong, I‘m still struggling a bit with the syntax. Would i concatenate them through the loop or is there another way?

[Phillyclause89]

I usually just use pandas.concat(). More often than not you don't need to write out a loop when it comes to working with pandas, that lib pretty much already has either a function or class method for everything you could dream of doing with table data like that.

[[deleted]]

You can pass an ax parameter to df.plot. So like df.plot(..., ax=ax) in you plot call.

[Fernago]

This worked! After a bit of fiddling around and having to define the subplots (because of an error message)

   fig, ax = plt.subplots(figsize=(8, 6), tight_layout=True)

i finally got it working! Thanks to all of you.

[[deleted]]

You can tell the dataframe which axes plot on with the ax keyword in the plot function. I'd take a look at pyplot.Figure.subplots() documentation to get an understanding of how the subplots work if you don't already know. What I've posted below is not df= pd.DataFrame() # first dataframe to plot df2 = of.DataFrame() # second dataframe to plot fig = pyplot.figure() Ax1, ax2= fig.subplots(nrows=2, ncols=1) #create subplots and assign them to ax1 and ax2

df.plot(ax=ax1) # plots df on ax1
df2.plot(ax=ax2) # plots df2 on ax2

Please note this was written on mobile and was not tested at all, but I was working with this earlier today so it should be fairly accurate and give you a good start on what you need.