I have this simple pandas dataframe with dates as index:
df=pd.DataFrame({'a':[20,30,12],'b':[15,18,18]},index=['2021-10-7','2021-10-8','2021-10-9']) df.index=pd.to_datetime(df.index)
when I try to plot a simple pandas.plot with only two dates in xaxis
df.iloc[-2:].plot()
it gives me the following plot with lot of numbers in axis
Plot works fine if I plot the entire db: db.plot()
Thank you for support
You can add below line after setting your index to make it work.
df.index.freq = 'D'
So Your entire code looks like this:
df=pd.DataFrame({'a':[20,30,12],'b':[15,18,18]},index=['2021-10-7','2021-10-8','2021-10-9'])
df.index = pd.to_datetime(df.index)
df.index.freq = 'D'
Alternatively:
You can also use date_range like below :
Please note this would work only if your data is like the one provided which has frequency of daily, You need to adjust in cases where the frequencies are different.
df=pd.DataFrame({'a':[20,30,12],'b':[15,18,18]},index=['2021-10-7','2021-10-8','2021-10-9'])
df.index=pd.date_range(start = '2021-10-07', end='2021-10-09')
Both approaches will give you same plot which you have mentioned in the question(similar to bottom one in the provided question)
Related
I have the attached DF that I am trying to plot however, the xvalues are the index from the DF when I would want them to be the actual episode names. Any recommendations here?DF pic
By first selecting the column from the DataFrame, and the plotting that you end up not "carrying over" those labels with you. You fix this two different ways:
plot from the DataFrame, not from the Series
top_episodes.plot(x="EpisodeTitle", y="Viewship(MM)", kind="bar")
Alternatively, set the index to be the EpisodeTitle, and then perform your column selection/plotting.
top_episodes.set_index("EpisodeTitle")["Viewship(MM)"].plot(kind="bar")
I'm trying to use seaborn dataframe functionality (e.g. passing column names to x, y and hue plot parameters) for my timeseries (in pandas datetime format) plots.
x should come from a timeseries column(converted from a pd.Series of strings with pd.to_datetime)
y should come from a float column
hue comes from a categorical column that I calculated.
There are multiple streams in the same series that I am trying to separate (and use the hue for separating them visually), and therefore they should not be connected by a line (like in a scatterplot)
I have tried the following plot types, each with a different problem:
sns.scatterplot: gets the plotting right and the labels right bus has problems with the xlimits, and I could not set them right with plt.xlim() using data.Dates.min and data.Dates.min
sns.lineplot: gets the limits and the labels right but I could not find a setting to disable the lines between the individual datapoints like in matplotlib. I tried the setting the markers and the dashes parameters to no avail.
sns.stripplot: my last try, plotted the datapoints correctly and got the xlimits right but messed the labels ticks
Example input data for easy reproduction:
dates = pd.to_datetime(('2017-11-15',
'2017-11-29',
'2017-12-15',
'2017-12-28',
'2018-01-15',
'2018-01-30',
'2018-02-15',
'2018-02-27',
'2018-03-15',
'2018-03-27',
'2018-04-13',
'2018-04-27',
'2018-05-15',
'2018-05-28',
'2018-06-15',
'2018-06-28',
'2018-07-13',
'2018-07-27'))
values = np.random.randn(len(dates))
clusters = np.random.randint(1, size=len(dates))
D = {'Dates': dates, 'Values': values, 'Clusters': clusters}
data = pd.DataFrame(D)
To each of the functions I am passing the same arguments:
sns.OneOfThePlottingFunctions(x='Dates',
y='Values',
hue='Clusters',
data=data)
plt.show()
So to recap, what I want is a plot that uses seaborn's pandas functionality, and plots points(not lines) with correct x limits and readable x labels :)
Any help would be greatly appreciated.
ax = sns.scatterplot(x='Dates', y='Values', hue='Clusters', data=data)
ax.set_xlim(data['Dates'].min(), data['Dates'].max())
When you already have time series data set but use internal dtype to index with date/time, you seem to be able to plot the index cleanly as here.
But when I already have data files with columns of date&time in its own format, such as [2009-01-01T00:00], is there a way to have this converted into the object that the plot can read? Currently my plot looks like the following.
Code:
dir = sorted(glob.glob("bsrn_txt_0100/*.txt"))
gen_raw = (pd.read_csv(file, sep='\t', encoding = "utf-8") for file in dir)
gen = pd.concat(gen_raw, ignore_index=True)
gen.drop(gen.columns[[1,2]], axis=1, inplace=True)
#gen['Date/Time'] = gen['Date/Time'][11:] -> cause error, didnt work
filter = gen[gen['Date/Time'].str.endswith('00') | gen['Date/Time'].str.endswith('30')]
filter['rad_tot'] = filter['Direct radiation [W/m**2]'] + filter['Diffuse radiation [W/m**2]']
lis = np.arange(35040) #used the number of rows, checked by printing. THis is for 2009-2010.
plt.xticks(lis, filter['Date/Time'])
plt.plot(lis, filter['rad_tot'], '.')
plt.title('test of generation 2009')
plt.xlabel('Date/Time')
plt.ylabel('radiation total [W/m**2]')
plt.show()
My other approach in mind was to use plotly. Yet again, its main purpose seems to feed in data on the internet. It would be best if I am familiar with all the modules and try for myself, but I am learning as I go to use pandas and matplotlib.
So I would like to ask whether there are anyone who experienced similar issues as I.
I think you need set labels to not visible by loop:
ax = df.plot(...)
spacing = 10
visible = ax.xaxis.get_ticklabels()[::spacing]
for label in ax.xaxis.get_ticklabels():
if label not in visible:
label.set_visible(False)
I can use DataFrameGroupBy.boxplot(...) to create a boxplot in the following way:
In [15]: df = pd.DataFrame({"gene_length":[100,100,100,200,200,200,300,300,300],
...: "gene_id":[1,1,1,2,2,2,3,3,3],
...: "density":[0.4,1.1,1.2,1.9,2.0,2.5,2.2,3.0,3.3],
...: "cohort":["USA","EUR","FIJ","USA","EUR","FIJ","USA","EUR","FIJ"]})
In [17]: df.groupby("cohort").boxplot(column="density",by="gene_id")
In [18]: plt.show()
This produces the following image:
This is exactly what I want, except instead of making three subplots, I want all the plots to be in one plot (with different colors for USA, EUR, and FIJ). I've tried
In [17]: df.groupby("cohort").boxplot(column="density",subplots=False,by="gene_id")
but it produces the error
KeyError: 'gene_id'
I think the problem has something to do with the fact that by="gene_id" is a keyword sent to the matplotlib boxplot method. If someone has a better way of producing the plot I am after, perhaps by using DataFrame.boxplot(?) instead, please respond here. Thanks so much!
To use the pure pandas functions, I think you should not GroupBy before calling boxplot, but instead, request to group by certain columns in the call to boxplot on the DataFrame itself:
df.boxplot(column='density',by=['gene_id','cohort'])
To get a better-looking result, you might want to consider using the Seaborn library. It is designed to help precisely with this sort of tasks:
sns.boxplot(data=df,x='gene_id',y='density',hue='cohort')
EDIT to take into account comment below
If you want to have each of your cohort boxplots stacked/superimposed for each gene_id, it's a bit more complicated (plus you might end up with quite an ugly output). You cannot do this using Seaborn, AFAIK, but you could with pandas directly, by using the position= parameter to boxplot (see doc). The catch it to generate the correct sequence of positions to place the boxplots where you want them, but you'll have to fix the tick labels and the legend yourself.
pos = [i for i in range(len(df.gene_id.unique())) for _ in range(len(df.cohort.unique()))]
df.boxplot(column='density',by=['gene_id','cohort'],positions=pos)
An alternative would be to use seaborn.swarmplot instead of using boxplot. A swarmplot plots every point instead of the synthetic representation of boxplots, but you can use the parameter split=False to get the points colored by cohort but stacked on top of each other for each gene_id.
sns.swarmplot(data=df,x='gene_id',y='density',hue='cohort', split=False)
Without knowing the actual content of your dataframe (number of points per gene and per cohort, and how separate they are in each cohort), it's hard to say which solution would be the most appropriate.
I'd like to apply functions to columns of a DataFrame when plotting them.
I understand that the standard way to plot when using Pandas is the .plot method.
How can I do math operations within this method, say for example multiply two columns in the plot?
Thanks!
Series actually have a plot method as well, so it should work to apply
(df['col1'] * df['col2']).plot()
Otherwise, if you need to do this more than once it would be the usual thing to make a new column in your dataframe:
df['newcol'] = df['col1'] * df['col2']