I am using seaborn(v.0.7.1) together with matplotlib(1.5.1) and pandas (v.0.18.1) to plot different clusters of data of different sizes as heat maps within a for loop as shown in the following code.
My issue is that since each cluster contains different number of rows, the final figures are of different sizes (i.e. the height and width of each box in the heat map is different across different heat maps)(see figures). Eventually, I would like to have figures of the same size (as explained above).
I have checked some parts of seabornand matplotlib documentations as well as stackoverflowbut since I do not know what the exact keywords are to look for (as evident in the question title itself) I have not been able to find any answer. [EDIT: Now I have updated the title based on a suggestion from #ImportanceOfBeingErnest. Previously the title was read: "Enforcing the same width across multiple plots".]
import numpy as np
import pandas as pd
clusters = pd.DataFrame([(1,'aaaaaaaaaaaaaaaaa'),(1,'b'), (1,'c'), (1,'d'), (2,'e'), (2,'f')])
clusters.columns = ['c', 'p']
clusters.set_index('c', inplace=True)
g = pd.DataFrame(np.ones((6,4)))
c= pd.DataFrame([(1,'aaaaaaaaaaaaaaaaa'),(2,'b'), (3,'c'), (4,'d'), (5,'e'), (6,'f')])
c.columns = ['i', 'R']
for i in range(1,3,1):
ee = clusters[clusters.index==i].p
inds = []
for v in ee:
inds.append(np.where(c.R.values == v)[0][0])
f, ax = plt.subplots(1, figsize=(13, 15))
ax = sns.heatmap(g.iloc[inds], square=True, ax=ax, cbar=True, linewidths=2, linecolor='k', cmap="Reds", cbar_kws={"shrink": .5},
vmin = math.floor(g.values.min()), vmax =math.ceil(g.values.max()))
null = ax.set_xticklabels(['a', 'b', 'c', 'd'], fontsize=15)
null = ax.set_yticklabels(c.R.values[inds][::-1], fontsize=15, rotation=0)
plt.tight_layout(pad=3)
[EDIT]: Now I have added some code to create a minimal, functional example as suggested by #Brian. Now I have noticed that the issue might have been caused by the text!
Under the following conditions
If only the squares in the saved images should have the same size and we don't care about the plot on screen and
We can omit the colorbar
the solution is rather straight forward.
One would define the size that one square should have in the final image squaresize = 50, find out the number of squares to draw in each dimension (n, m) and adjust the figure size as
figwidth = m*squaresize/float(dpi)
figheight = n*squaresize/float(dpi)
where dpi denotes the pixels per inch.
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt
dpi=100
squaresize = 50 # pixels
n = 3
m = 4
data = np.random.rand(n,m)
figwidth = m*squaresize/float(dpi)
figheight = n*squaresize/float(dpi)
f, ax = plt.subplots(1, figsize=(figwidth, figheight), dpi=dpi)
f.subplots_adjust(left=0, right=1, bottom=0, top=1)
ax = sns.heatmap(data, square=True, ax=ax, cbar=False)
plt.savefig(__file__+".png", dpi=dpi, bbox_inches="tight")
The bbox_inches="tight" makes sure that the labels etc. are still drawn (i.e. the final figure size will be larger than the one calculated here, depending on how much space the labels need).
To apply this example to your case you'd still need to find out how many rows and columns you have in the heatmap depending on the dataframe, but as I don't have it's structure, it's hard to provide a general solution.
Related
I have a plot that looks as follows:
I want to put labels for both the lineplot and the markers in red. However the legend is not appearning because its the plot is taking out its space.
Update
it turns out I cannot put several strings in plt.legend()
I made the figure bigger by using the following:
fig = plt.gcf()
fig.set_size_inches(18.5, 10.5)
However now I have only one label in the legend, with the marker appearing on the lineplot while I rather want two: one for the marker alone and another for the line alone:
Updated code:
plt.plot(range(len(y)), y, '-bD', c='blue', markerfacecolor='red', markeredgecolor='k', markevery=rare_cases, label='%s' % target_var_name)
fig = plt.gcf()
fig.set_size_inches(18.5, 10.5)
# changed this over here
plt.legend()
plt.savefig(output_folder + fig_name)
plt.close()
What you want to do (have two labels for a single object) is not completely impossible but it's MUCH easier to plot separately the line and the rare values, e.g.
# boilerplate
import numpy as np
import matplotlib.pyplot as plt
# synthesize some data
N = 501
t = np.linspace(0, 10, N)
s = np.sin(np.pi*t)
rare = np.zeros(N, dtype=bool); rare[:20]=True; np.random.shuffle(rare)
plt.plot(t, s, label='Curve')
plt.scatter(t[rare], s[rare], label='rare')
plt.legend()
plt.show()
Update
[...] it turns out I cannot put several strings in plt.legend()
Well, you can, as long as ① the several strings are in an iterable (a tuple or a list) and ② the number of strings (i.e., labels) equals the number of artists (i.e., thingies) in the plot.
plt.legend(('a', 'b', 'c'))
I'm trying to plot a boxplot for two different datasets on the same plot. The x axis are the hours in a day, while the y axis goes from 0 to 1 (let's call it Efficiency). I would like to have different markers for the means of each dataset' boxes. I use the 'meanprops' for seaborn but that changes the marker style for both datasets at the same time. I've added 2000 lines of data in the excel that can be downloaded here. The values might not coincide with the ones in the picture but should be enough.
Basically I want the red squares to be blue on the orange boxplot, and red on the blue boxplot. Here is what I managed to do so far:
I tried changing the meanprops by using a dictionary with the labels as keys , but it seems to be entering a loop (in PyCharm is says Evaluating...)
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
#make sure you have your path sorted out
group1 = pd.read_excel('group1.xls')
ax,fig = plt.subplots(figsize = (20,10))
#does not work
#ax = sns.boxplot(data=group1, x='hour', y='M1_eff', hue='labels',showfliers=False, showmeans=True,\
# meanprops={"marker":{'7':"s",'8':'s'},"markerfacecolor":{'7':"white",'8':'white'},
#"markeredgecolor":{'7':"blue",'8':'red'})
#works but produces similar markers
ax = sns.boxplot(data=group1, x='hour', y='M1_eff', hue='labels',showfliers=False, showmeans=True,\
meanprops={"marker":"s","markerfacecolor":"white", "markeredgecolor":"blue"})
plt.legend(title='Groups', loc=2, bbox_to_anchor=(1, 1),borderaxespad=0.5)
# Add transparency to colors
for patch in ax.artists:
r, g, b, a = patch.get_facecolor()
patch.set_facecolor((r, g, b, .4))
ax.set_xlabel("Hours",fontsize=14)
ax.set_ylabel("M1 Efficiency",fontsize=14)
ax.tick_params(labelsize=10)
plt.show()
I also tried the FacetGrid but to no avail (Stops at 'Evaluating...'):
g = sns.FacetGrid(group1, col="M1_eff", hue="labels",hue_kws=dict(marker=["^", "v"]))
g = (g.map(plt.boxplot, "hour", "M1_eff")
.add_legend())
g.show()
Any help is appreciated!
I don't think you can do this using sns.boxplot() directly. I think you'll have to draw the means "by hand"
N=100
df = pd.DataFrame({'hour':np.random.randint(0,3,size=(N,)),
'M1_eff': np.random.random(size=(N,)),
'labels':np.random.choice([7,8],size=(N,))})
x_col = 'hour'
y_col = 'M1_eff'
hue_col = 'labels'
width = 0.8
hue_order=[7,8]
marker_colors = ['red','blue']
# get the offsets used by boxplot when hue-nesting is used
# https://github.com/mwaskom/seaborn/blob/c73055b2a9d9830c6fbbace07127c370389d04dd/seaborn/categorical.py#L367
n_levels = len(hue_order)
each_width = width / n_levels
offsets = np.linspace(0, width - each_width, n_levels)
offsets -= offsets.mean()
fig, ax = plt.subplots()
ax = sns.boxplot(data=df, x=x_col, y=y_col, hue=hue_col, hue_order=hue_order, showfliers=False, showmeans=False)
means = df.groupby([hue_col,x_col])[y_col].mean()
for (gr,temp),o,c in zip(means.groupby(level=0),offsets,marker_colors):
ax.plot(np.arange(temp.values.size)+o, temp.values, 's', c=c)
I have a compiled a dataframe that contains USGS streamflow data at several different streamgages. Now I want to create a Gantt chart similar to this. Currently, my data has columns as site names and a date index as rows.
Here is a sample of my data.
The problem with the Gantt chart example I linked is that my data has gaps between the start and end dates that would normally define the horizontal time-lines. Many of the examples I found only account for the start and end date, but not missing values that may be in between. How do I account for the gaps where there is no data (blanks or nan in those slots for values) for some of the sites?
First, I have a plot that shows where the missing data is.
import missingno as msno
msno.bar(dfp)
Now, I want time on the x-axis and a horizontal line on the y-axis that tracks when the sites contain data at those times. I know how to do this the brute force way, which would mean manually picking out the start and end dates where there is valid data (which I made up below).
from datetime import datetime
import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.dates as dt
df=[('RIO GRANDE AT EMBUDO, NM','2015-7-22','2015-12-7'),
('RIO GRANDE AT EMBUDO, NM','2016-1-22','2016-8-5'),
('RIO GRANDE DEL RANCHO NEAR TALPA, NM','2014-12-10','2015-12-14'),
('RIO GRANDE DEL RANCHO NEAR TALPA, NM','2017-1-10','2017-11-25'),
('RIO GRANDE AT OTOWI BRIDGE, NM','2015-8-17','2017-8-21'),
('RIO GRANDE BLW TAOS JUNCTION BRIDGE NEAR TAOS, NM','2015-9-1','2016-6-1'),
('RIO GRANDE NEAR CERRO, NM','2016-1-2','2016-3-15'),
]
df=pd.DataFrame(data=df)
df.columns = ['A', 'Beg', 'End']
df['Beg'] = pd.to_datetime(df['Beg'])
df['End'] = pd.to_datetime(df['End'])
fig = plt.figure(figsize=(10,8))
ax = fig.add_subplot(111)
ax = ax.xaxis_date()
ax = plt.hlines(df['A'], dt.date2num(df['Beg']), dt.date2num(df['End']))
How do I make a figure (like the one shown above) with the dataframe I provided as an example? Ideally I want to avoid the brute force method.
Please note: values of zero are considered valid data points.
Thank you in advance for your feedback!
Find date ranges of non-null data
2020-02-12 Edit to clarify logic in loop
df = pd.read_excel('Downloads/output.xlsx', index_col='date')
Make sure the dates are in order:
df.sort_index(inplace=True)
Loop thru the data and find the edges of the good data ranges. Get the corresponding index values and the name of the gauge and collect them all in a list:
# Looping feels like defeat. However, I'm not clever enough to avoid it
good_ranges = []
for i in df:
col = df[i]
gauge_name = col.name
# Start of good data block defined by a number preceeded by a NaN
start_mark = (col.notnull() & col.shift().isnull())
start = col[start_mark].index
# End of good data block defined by a number followed by a Nan
end_mark = (col.notnull() & col.shift(-1).isnull())
end = col[end_mark].index
for s, e in zip(start, end):
good_ranges.append((gauge_name, s, e))
good_ranges = pd.DataFrame(good_ranges, columns=['gauge', 'start', 'end'])
Plotting
Nothing new here. Copied pretty much straight from your question:
fig = plt.figure(figsize=(10,8))
ax = fig.add_subplot(111)
ax = ax.xaxis_date()
ax = plt.hlines(good_ranges['gauge'],
dt.date2num(good_ranges['start']),
dt.date2num(good_ranges['end']))
fig.tight_layout()
Here's an approach that you could use, it's a bit hacky so perhaps some else will produce a better solution but it should produce your desired output. First use pd.where to replace non NaN values with an integer which will later determine the position of the lines on y-axis later, I do this row by row so that all data which belongs together will be at the same height. If you want to increase the spacing between the lines of the gantt chart you can add a number to i, I've provided an example in the comments in the code block below.
The y-labels and their positions are produced in the data munging steps, so this method will work regardless of the number of columns and will position the labels correctly when you change the spacing described above.
This approach returns matplotlib.pyplot.axes and matplotlib.pyplot.Figure object, so you can adjust the asthetics of the chart to suit your purposes (i.e. change the thickness of the lines, colours etc.). Link to docs.
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
df = pd.read_excel('output.xlsx')
dates = pd.to_datetime(df.date)
df.index = dates
df = df.drop('date', axis=1)
new_rows = [df[s].where(df[s].isna(), i) for i, s in enumerate(df, 1)]
# To increase spacing between lines add a number to i, eg. below:
# [df[s].where(df[s].isna(), i+3) for i, s in enumerate(df, 1)]
new_df = pd.DataFrame(new_rows)
### Plotting ###
fig, ax = plt.subplots() # Create axes object to pass to pandas df.plot()
ax = new_df.transpose().plot(figsize=(40,10), ax=ax, legend=False, fontsize=20)
list_of_sites = new_df.transpose().columns.to_list() # For y tick labels
x_tick_location = new_df.iloc[:, 0].values # For y tick positions
ax.set_yticks(x_tick_location) # Place ticks in correct positions
ax.set_yticklabels(list_of_sites) # Update labels to site names
Before I start I want to say that I've tried follow this and this post on the same problem however they are doing it with imshow heatmaps unlike 2d histogram like I'm doing.
Here is my code(the actual data has been replaced by randomly generated data but the gist is the same):
import matplotlib.pyplot as plt
import numpy as np
def subplots_hist_2d(x_data, y_data, x_labels, y_labels, titles):
fig, a = plt.subplots(2, 2)
a = a.ravel()
for idx, ax in enumerate(a):
image = ax.hist2d(x_data[idx], y_data[idx], bins=50, range=[[-2, 2],[-2, 2]])
ax.set_title(titles[idx], fontsize=12)
ax.set_xlabel(x_labels[idx])
ax.set_ylabel(y_labels[idx])
ax.set_aspect("equal")
cb = fig.colorbar(image[idx])
cb.set_label("Intensity", rotation=270)
# pad = how big overall pic is
# w_pad = how separate they're left to right
# h_pad = how separate they're top to bottom
plt.tight_layout(pad=-1, w_pad=-10, h_pad=0.5)
x1, y1 = np.random.uniform(-2, 2, 10000), np.random.uniform(-2, 2, 10000)
x2, y2 = np.random.uniform(-2, 2, 10000), np.random.uniform(-2, 2, 10000)
x3, y3 = np.random.uniform(-2, 2, 10000), np.random.uniform(-2, 2, 10000)
x4, y4 = np.random.uniform(-2, 2, 10000), np.random.uniform(-2, 2, 10000)
x_data = [x1, x2, x3, x4]
y_data = [y1, y2, y3, y4]
x_labels = ["x1", "x2", "x3", "x4"]
y_labels = ["y1", "y2", "y3", "y4"]
titles = ["1", "2", "3", "4"]
subplots_hist_2d(x_data, y_data, x_labels, y_labels, titles)
And this is what it's generating:
So now my problem is that I could not for the life of me make the colorbar apply for all 4 of the histograms. Also for some reason the bottom right histogram seems to behave weirdly compared with the others. In the links that I've posted their methods don't seem to use a = a.ravel() and I'm only using it here because it's the only way that allows me to plot my 4 histograms as subplots. Help?
EDIT:
Thomas Kuhn your new method actually solved all of my problem until I put my labels down and tried to use plt.tight_layout() to sort out the overlaps. It seems that if I put down the specific parameters in plt.tight_layout(pad=i, w_pad=0, h_pad=0) then the colorbar starts to misbehave. I'll now explain my problem.
I have made some changes to your new method so that it suits what I want, like this
def test_hist_2d(x_data, y_data, x_labels, y_labels, titles):
nrows, ncols = 2, 2
fig, axes = plt.subplots(nrows, ncols, sharex=True, sharey=True)
##produce the actual data and compute the histograms
mappables=[]
for (i, j), ax in np.ndenumerate(axes):
H, xedges, yedges = np.histogram2d(x_data[i][j], y_data[i][j], bins=50, range=[[-2, 2],[-2, 2]])
ax.set_title(titles[i][j], fontsize=12)
ax.set_xlabel(x_labels[i][j])
ax.set_ylabel(y_labels[i][j])
ax.set_aspect("equal")
mappables.append(H)
##the min and max values of all histograms
vmin = np.min(mappables)
vmax = np.max(mappables)
##second loop for visualisation
for ax, H in zip(axes.ravel(), mappables):
im = ax.imshow(H,vmin=vmin, vmax=vmax, extent=[-2,2,-2,2])
##colorbar using solution from linked question
fig.colorbar(im,ax=axes.ravel())
plt.show()
# plt.tight_layout
# plt.tight_layout(pad=i, w_pad=0, h_pad=0)
Now if I try to generate my data, in this case:
phi, cos_theta = get_angles(runs)
detector_x1, detector_y1, smeared_x1, smeared_y1 = detection_vectorised(1.5, cos_theta, phi)
detector_x2, detector_y2, smeared_x2, smeared_y2 = detection_vectorised(1, cos_theta, phi)
detector_x3, detector_y3, smeared_x3, smeared_y3 = detection_vectorised(0.5, cos_theta, phi)
detector_x4, detector_y4, smeared_x4, smeared_y4 = detection_vectorised(0, cos_theta, phi)
Here detector_x, detector_y, smeared_x, smeared_y are all lists of data point
So now I put them into 2x2 lists so that they can be unpacked suitably by my plotting function, as such:
data_x = [[detector_x1, detector_x2], [detector_x3, detector_x4]]
data_y = [[detector_y1, detector_y2], [detector_y3, detector_y4]]
x_labels = [["x positions(m)", "x positions(m)"], ["x positions(m)", "x positions(m)"]]
y_labels = [["y positions(m)", "y positions(m)"], ["y positions(m)", "y positions(m)"]]
titles = [["0.5m from detector", "1.0m from detector"], ["1.5m from detector", "2.0m from detector"]]
I now run my code with
test_hist_2d(data_x, data_y, x_labels, y_labels, titles)
with just plt.show() turned on, it gives this:
which is great because data and visual wise, it is exactly what I want i.e. the colormap corresponds to all 4 histograms. However, since the labels are overlapping with the titles, I thought I would just run the same thing but this time with plt.tight_layout(pad=a, w_pad=b, h_pad=c) hoping that I would be able to adjust the overlapping labels problem. However this time it doesn't matter how I change the numbers a, b and c, I always get my colorbar lying on the second column of graphs, like this:
Now changing a only makes the overall subplots bigger or smaller, and the best I could do was to adjust it with plt.tight_layout(pad=-10, w_pad=-15, h_pad=0), which looks like this
So it seems that whatever your new method is doing, it made the whole plot lost its adjustability. Your solution, as wonderful as it is at solving one problem, in return, created another. So what would be the best thing to do here?
Edit 2:
Using fig, axes = plt.subplots(nrows, ncols, sharex=True, sharey=True, constrained_layout=True) along with plt.show() gives
As you can see there's still a vertical gap between the columns of subplots for which not even using plt.subplots_adjust() can get rid of.
Edit:
As has been noted in the comments, the biggest problem here is actually to make the colorbar for many histograms meaningful, as ax.hist2d will always scale the histogram data it receives from numpy. It may therefore be best to first calculated the 2d histogram data using numpy and then use again imshow to visualise it. This way, also the solutions of the linked question can be applied. To make the problem with the normalisation more visible, I put some effort into producing some qualitatively different 2d histograms using scipy.stats.multivariate_normal, which shows how the height of the histogram can change quite dramatically even though the number of samples is the same in each figure.
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import gridspec as gs
from scipy.stats import multivariate_normal
##opening figure and axes
nrows=3
ncols=3
fig, axes = plt.subplots(nrows,ncols)
##generate some random data for the distributions
means = np.random.rand(nrows,ncols,2)
sigmas = np.random.rand(nrows,ncols,2)
thetas = np.random.rand(nrows,ncols)*np.pi*2
##produce the actual data and compute the histograms
mappables=[]
for mean,sigma,theta in zip( means.reshape(-1,2), sigmas.reshape(-1,2), thetas.reshape(-1)):
##the data (only cosmetics):
c, s = np.cos(theta), np.sin(theta)
rot = np.array(((c,-s), (s, c)))
cov = rot#np.diag(sigma)#rot.T
rv = multivariate_normal(mean,cov)
data = rv.rvs(size = 10000)
##the 2d histogram from numpy
H,xedges,yedges = np.histogram2d(data[:,0], data[:,1], bins=50, range=[[-2, 2],[-2, 2]])
mappables.append(H)
##the min and max values of all histograms
vmin = np.min(mappables)
vmax = np.max(mappables)
##second loop for visualisation
for ax,H in zip(axes.ravel(),mappables):
im = ax.imshow(H,vmin=vmin, vmax=vmax, extent=[-2,2,-2,2])
##colorbar using solution from linked question
fig.colorbar(im,ax=axes.ravel())
plt.show()
This code produces a figure like this:
Old Answer:
One way to solve your problem is to generate the space for your colorbar explicitly. You can use a GridSpec instance to define how wide your colorbar should be. Below your subplots_hist_2d() function with a few modifications. Note that your use of tight_layout() shifted the colorbar into a funny place, hence the replacement. If you want the plots closer to each other, I'd rather recommend to play with the aspect ratio of the figure.
def subplots_hist_2d(x_data, y_data, x_labels, y_labels, titles):
## fig, a = plt.subplots(2, 2)
fig = plt.figure()
g = gs.GridSpec(nrows=2, ncols=3, width_ratios=[1,1,0.05])
a = [fig.add_subplot(g[n,m]) for n in range(2) for m in range(2)]
cax = fig.add_subplot(g[:,2])
## a = a.ravel()
for idx, ax in enumerate(a):
image = ax.hist2d(x_data[idx], y_data[idx], bins=50, range=[[-2, 2],[-2, 2]])
ax.set_title(titles[idx], fontsize=12)
ax.set_xlabel(x_labels[idx])
ax.set_ylabel(y_labels[idx])
ax.set_aspect("equal")
## cb = fig.colorbar(image[-1],ax=a)
cb = fig.colorbar(image[-1], cax=cax)
cb.set_label("Intensity", rotation=270)
# pad = how big overall pic is
# w_pad = how separate they're left to right
# h_pad = how separate they're top to bottom
## plt.tight_layout(pad=-1, w_pad=-10, h_pad=0.5)
fig.tight_layout()
Using this modified function, I get the following output:
I can create a simple columnar diagram in a matplotlib according to the 'simple' dictionary:
import matplotlib.pyplot as plt
D = {u'Label1':26, u'Label2': 17, u'Label3':30}
plt.bar(range(len(D)), D.values(), align='center')
plt.xticks(range(len(D)), D.keys())
plt.show()
But, how do I create curved line on the text and numeric data of this dictionarie, I do not know?
Т_OLD = {'10': 'need1', '11': 'need2', '12': 'need1', '13': 'need2', '14': 'need1'}
Like the picture below
You may use numpy to convert the dictionary to an array with two columns, which can be plotted.
import matplotlib.pyplot as plt
import numpy as np
T_OLD = {'10' : 'need1', '11':'need2', '12':'need1', '13':'need2','14':'need1'}
x = list(zip(*T_OLD.items()))
# sort array, since dictionary is unsorted
x = np.array(x)[:,np.argsort(x[0])].T
# let second column be "True" if "need2", else be "False
x[:,1] = (x[:,1] == "need2").astype(int)
# plot the two columns of the array
plt.plot(x[:,0], x[:,1])
#set the labels accordinly
plt.gca().set_yticks([0,1])
plt.gca().set_yticklabels(['need1', 'need2'])
plt.show()
The following would be a version, which is independent on the actual content of the dictionary; only assumption is that the keys can be converted to floats.
import matplotlib.pyplot as plt
import numpy as np
T_OLD = {'10': 'run', '11': 'tea', '12': 'mathematics', '13': 'run', '14' :'chemistry'}
x = np.array(list(zip(*T_OLD.items())))
u, ind = np.unique(x[1,:], return_inverse=True)
x[1,:] = ind
x = x.astype(float)[:,np.argsort(x[0])].T
# plot the two columns of the array
plt.plot(x[:,0], x[:,1])
#set the labels accordinly
plt.gca().set_yticks(range(len(u)))
plt.gca().set_yticklabels(u)
plt.show()
Use numeric values for your y-axis ticks, and then map them to desired strings with plt.yticks():
import matplotlib.pyplot as plt
import pandas as pd
# example data
times = pd.date_range(start='2017-10-17 00:00', end='2017-10-17 5:00', freq='H')
data = np.random.choice([0,1], size=len(times))
data_labels = ['need1','need2']
fig, ax = plt.subplots()
ax.plot(times, data, marker='o', linestyle="None")
plt.yticks(data, data_labels)
plt.xlabel("time")
Note: It's generally not a good idea to use a line graph to represent categorical changes in time (e.g. from need1 to need2). Doing that gives the visual impression of a continuum between time points, which may not be accurate. Here, I changed the plotting style to points instead of lines. If for some reason you need the lines, just remove linestyle="None" from the call to plt.plot().
UPDATE
(per comments)
To make this work with a y-axis category set of arbitrary length, use ax.set_yticks() and ax.set_yticklabels() to map to y-axis values.
For example, given a set of potential y-axis values labels, let N be the size of a subset of labels (here we'll set it to 4, but it could be any size).
Then draw a random sample data of y values and plot against time, labeling the y-axis ticks based on the full set labels. Note that we still use set_yticks() first with numerical markers, and then replace with our category labels with set_yticklabels().
labels = np.array(['A','B','C','D','E','F','G'])
N = 4
# example data
times = pd.date_range(start='2017-10-17 00:00', end='2017-10-17 5:00', freq='H')
data = np.random.choice(np.arange(len(labels)), size=len(times))
fig, ax = plt.subplots(figsize=(15,10))
ax.plot(times, data, marker='o', linestyle="None")
ax.set_yticks(np.arange(len(labels)))
ax.set_yticklabels(labels)
plt.xlabel("time")
This gives the exact desired plot:
import matplotlib.pyplot as plt
from collections import OrderedDict
T_OLD = {'10' : 'need1', '11':'need2', '12':'need1', '13':'need2','14':'need1'}
T_SRT = OrderedDict(sorted(T_OLD.items(), key=lambda t: t[0]))
plt.plot(map(int, T_SRT.keys()), map(lambda x: int(x[-1]), T_SRT.values()),'r')
plt.ylim([0.9,2.1])
ax = plt.gca()
ax.set_yticks([1,2])
ax.set_yticklabels(['need1', 'need2'])
plt.title('T_OLD')
plt.xlabel('time')
plt.ylabel('need')
plt.show()
For Python 3.X the plotting lines needs to explicitly convert the map() output to lists:
plt.plot(list(map(int, T_SRT.keys())), list(map(lambda x: int(x[-1]), T_SRT.values())),'r')
as in Python 3.X map() returns an iterator as opposed to a list in Python 2.7.
The plot uses the dictionary keys converted to ints and last elements of need1 or need2, also converted to ints. This relies on the particular structure of your data, if the values where need1 and need3 it would need a couple more operations.
After plotting and changing the axes limits, the program simply modifies the tick labels at y positions 1 and 2. It then also adds the title and the x and y axis labels.
Important part is that the dictionary/input data has to be sorted. One way to do it is to use OrderedDict. Here T_SRT is an OrderedDict object sorted by keys in T_OLD.
The output is:
This is a more general case for more values/labels in T_OLD. It assumes that the label is always 'needX' where X is any number. This can readily be done for a general case of any string preceding the number though it would require more processing,
import matplotlib.pyplot as plt
from collections import OrderedDict
import re
T_OLD = {'10' : 'need1', '11':'need8', '12':'need11', '13':'need1','14':'need3'}
T_SRT = OrderedDict(sorted(T_OLD.items(), key=lambda t: t[0]))
x_val = list(map(int, T_SRT.keys()))
y_val = list(map(lambda x: int(re.findall(r'\d+', x)[-1]), T_SRT.values()))
plt.plot(x_val, y_val,'r')
plt.ylim([0.9*min(y_val),1.1*max(y_val)])
ax = plt.gca()
y_axis = list(set(y_val))
ax.set_yticks(y_axis)
ax.set_yticklabels(['need' + str(i) for i in y_axis])
plt.title('T_OLD')
plt.xlabel('time')
plt.ylabel('need')
plt.show()
This solution finds the number at the end of the label using re.findall to accommodate for the possibility of multi-digit numbers. Previous solution just took the last component of the string because numbers were single digit. It still assumes that the number for plotting position is the last number in the string, hence the [-1]. Again for Python 3.X map output is explicitly converted to list, step not necessary in Python 2.7.
The labels are now generated by first selecting unique y-values using set and then renaming their labels through concatenation of the strings 'need' with its corresponding integer.
The limits of y-axis are set as 0.9 of the minimum value and 1.1 of the maximum value. Rest of the formatting is as before.
The result for this test case is: