On Mon, May 4, 2009 at 9:49 AM, Olivier Benoist wrote:
Hi,
I'm new with matplotlib.

I need to make a graph with the X axis represents time in hours and
minutes. My script don't works, I want to display all the values of time
that I have.
I use a list of string like this :
t=['0015', '0030', '0045', '0100', '0115', '0130', '0145', '0200',
'0215', '0230', '0245', '0300', '03
15', '0330', '0345', '0400', '0415', '0430', '0445', '0500', '0515',
'0530', '0545', '0600', '0615',
'0630', '0645', '0700', '0715', '0730', '0745', '0800', '0815', '0830',
'0845', '0900', '0915', '09
30', '0945', '1000', '1015', '1030', '1045', '1100', '1115', '1130',
'1145', '1200', '1215', '1230',
'1245', '1300', '1315', '1330', '1345', '1400', '1415']

ax.plot(t, y)

I tried to convert hours and minutes to the base 100 ( , it works but I
can not show on the x-axis the hours, minutes.
I tried to use plot_date, but I don't understand "x and/or y can be a
sequence of dates represented as float days since 0001-01-01 UTC."

Could you help me, please ?

You don't necessarily need to use plot_date. Try this:

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import FuncFormatter, MultipleLocator

times = ['0015', '0030', '0045', '0100', '0115', '0130', '0145', '0200', '0215',
'0230', '0245', '0300', '0315', '0330', '0345', '0400', '0415', '0430',
'0445', '0500', '0515', '0530', '0545', '0600', '0615', '0630', '0645',
'0700', '0715', '0730', '0745', '0800', '0815', '0830', '0845', '0900',
'0915', '0930', '0945', '1000', '1015', '1030', '1045', '1100', '1115',
'1130', '1145', '1200', '1215', '1230', '1245', '1300', '1315', '1330',
'1345', '1400', '1415']

# Conver the string time values into the corresponding number of minutes
minutes = np.array([int(t[:2])*60 + int(t[2:]) for t in times])

y = np.random.rand(*minutes.shape)
plt.plot(minutes, y)
ax = plt.gca()

# Set the formatter to take a value in minutes and convert to hour:minute
ax.xaxis.set_major_formatter(FuncFormatter(
lambda t,p : '%02d:%02d' % (t//60, t%60)))

# Set up placing tick marks every 15 minutes
ax.xaxis.set_major_locator(MultipleLocator(15))

# Used to rotate all of the ticks so that they fit on the plot.
# ha='center' aligns them better to the tick marks
fig = plt.gcf()
fig.autofmt_xdate(rotation=90, ha='center')
plt.show()

Ryan

--
Ryan May