Asking User For Input Before Plotting Selected Points

Hi Guys, I'm using Python 2.7.3, How can I ask the user to enter "from datetime" & "to datetime" then plot the graph
For eg. when user
from datetime: 21/7/2014 0:00
to datetime: 22/7/2014 23:57

from datetime import datetime
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
x = []
y = []
t = []
fig = plt.figure()
rect = fig.patch
rect.set_facecolor('#31312e')
readFile = open('data.txt', 'r')
sepFile = readFile.read().split('\n')
readFile.close()
for idx, plotPair in enumerate(sepFile):
    if plotPair in '. ':
        # skip. or space
        continue
    if idx > 1:  # to skip the first line
        xAndY = plotPair.split(',')
        time_string = xAndY[0]
        time_string1 = datetime.strptime(time_string, '%d/%m/%Y %H:%M')
        t.append(time_string1)
        y.append(float(xAndY[1]))
ax1 = fig.add_subplot(1, 1, 1, axisbg='white')
ax1.xaxis.set_major_formatter(mdates.DateFormatter('%d/%m/%Y %H:%M'))
ax1.plot(t, y, 'c', linewidth=3.3)
plt.title('IRRADIANCE')
plt.xlabel('TIME')
fig.autofmt_xdate(rotation=45)
fig.tight_layout()
plt.show()

[Gribouillis]

Install humanfriendly from pypi (pip install humanfriendly), then

from datetime import datetime
from humanfriendly import parse_date

s = raw_input('From datetime: ')
dt = datetime(*parse_date(s))
print(dt)

so since i want two timings from the user before plotting, is this how the codes will look? [the graph will be plotting just the timing between these two timings]:

    from datetime import datetime
    from humanfriendly import parse_date
    import matplotlib.pyplot as plt
    import matplotlib.dates as mdates


    s = raw_input('From datetime: ')
    s2 = raw_input('To datetime: ')
    dt = datetime(*parsedate(s))
    print(dt)


    x = []
    y = []
    t = []

    fig = plt.figure()
    rect = fig.patch
    rect.set_facecolor('#31312e')
    readFile = open('data.txt', 'r')
    sepFile = readFile.read().split('\n')
    readFile.close()
    for idx, plotPair in enumerate(sepFile):
        if plotPair in '. ':
            # skip. or space
            continue
        if idx > 1:  # to skip the first line
            xAndY = plotPair.split(',')
            time_string = xAndY[0]
            time_string1 = datetime.strptime(time_string, '%d/%m/%Y %H:%M')
            t.append(time_string1)
            y.append(float(xAndY[1]))
    ax1 = fig.add_subplot(1, 1, 1, axisbg='white')
    ax1.xaxis.set_major_formatter(mdates.DateFormatter('%d/%m/%Y %H:%M'))
    ax1.plot(t, y, 'c', linewidth=3.3)
    plt.title('IRRADIANCE')
    plt.xlabel('TIME')
    fig.autofmt_xdate(rotation=45)
    fig.tight_layout()
    plt.show()

[Gribouillis]

Yes, only you need to parse the two dates and may be write a loop to catch user errors, for example

from humanfriendly import parse_date, InvalidDate
from datetime import datetime

def ask_date(msg):
    while True:
        try:
            s = raw_input(msg)
            return datetime(*parse_date(s))
        except (InvalidDate, ValueError) as err:
            print(err)

dt1 = ask_date("From datetime: ")
dt2 = ask_date("To datetime: ")

You must also use dt1 and dt2 somewhere later in the code.

Edit: changed the except clause to catch ValueError.

hi Gribouillis, i'll try your suggestion and get back to you, thanks alot for the help!

how can i ask the user for the input on the graph window instead of on the python shell window ?

this is the code: but the program ask the user input on the python shell window before the graph window appear

from datetime import datetime
import matplotlib.pyplot as plt
import matplotlib.dates as mdates

x = []
y = []
t = []

fig = plt.figure()
rect = fig.patch
rect.set_facecolor('#31312e')
readFile = open('data.txt', 'r')
sepFile = readFile.read().split('\n')
readFile.close()

startTime = raw_input('please enter start time in format like 21/7/2014 0:00 :')
endTime   = raw_input('please enter end time in format like 22/7/2014 23:57 :') 

# startTime = '21/7/2014 0:02'
# endTime = '22/7/2014 23:58'
startTime = datetime.strptime(startTime, '%d/%m/%Y %H:%M')
endTime = datetime.strptime(endTime, '%d/%m/%Y %H:%M')


for idx, plotPair in enumerate(sepFile):
    if plotPair in '. ':
        # skip. or space
        continue
    if idx > 1:  # to skip the first line
        xAndY = plotPair.split(',')
        time_string = xAndY[0]
        time_string1 = datetime.strptime(time_string, '%d/%m/%Y %H:%M')
        if startTime<=time_string1 <=endTime:
            t.append(time_string1)
            y.append(float(xAndY[1]))
ax1 = fig.add_subplot(1, 1, 1, axisbg='white')
ax1.xaxis.set_major_formatter(mdates.DateFormatter('%d/%m/%Y %H:%M'))
ax1.plot(t, y, 'c', linewidth=3.3)
plt.title('IRRADIANCE')
plt.xlabel('TIME')
fig.autofmt_xdate(rotation=45)
fig.tight_layout()
plt.show()

[Gribouillis]

I don't think you can do that with matplotlib. You'll have to use one of the gui toolkits to build a dialog widget.