lst1 = list('a list of characterstrings')
for item in set(lst1):
    print item, 'counted', lst1.count(item), 'times'
 
"""
result =
a counted 3 times
  counted 3 times  (space)
c counted 2 times
e counted 1 times
...
"""

# reverse the spelling of an input string
# string reverse slice [::-1] introduced in Python23
# reversed() introduced in Python24
 
text = raw_input("Enter a string: ")
print text[::-1]
 
# or
print raw_input("Enter a string: ")[::-1]
 
# or
print ''.join(reversed(raw_input("Enter a string: ")))

# sort a list of numeric strings:
 
list1 = ['0', '100', '28', '39', '1', '1003']
 
print "Original list of numeric strings:"
print list1
 
print "Sort as strings:"
list1.sort()
print list1 # ['0', '1', '100', '1003', '28', '39']
 
print "Sort as integers (Python24):"
list1.sort(key=int)
print list1 # ['0', '1', '28', '39', '100', '1003']

# sort two lists in parallel ...
# create two lists of same length
list1 = ['one', 'two', 'three', 'four']
list2 = ['uno', 'dos', 'tres', 'cuatro']
 
# create a list of tuples, (english, spanish) pairs
data = zip(list1, list2)
print data # [('one', 'uno'), ('two', 'dos'), ('three', 'tres'), ('four', 'cuatro')]
 
# can use parallel looping to display result ...
for english, spanish in data:
    print english, spanish # one uno etc.
 
# each whole tuple will be sorted
data.sort()
print data # [('four', 'cuatro'), ('one', 'uno'), ('three', 'tres'), ('two', 'dos')]
 
# if you need two lists again after sorting then use ...
list3, list4 = map(lambda t: list(t), zip(*data))
print list3 # ['four', 'one', 'three', 'two']
print list4 # ['cuatro', 'uno', 'tres', 'dos']
 
# if you need just two tuples use ...
tuple1, tuple2 = zip(*data)
print tuple1 # ('four', 'one', 'three', 'two')
print tuple2 # ('cuatro', 'uno', 'tres', 'dos')

# bind and show a key event with Tkinter 
 
from Tkinter import *
 
root = Tk()
prompt = '      Press any key      '
label1 = Label(root, text=prompt, width=len(prompt))
label1.pack()
 
def key(event):
    if event.char == event.keysym:
        msg = 'Normal Key %r' % event.char
    elif len(event.char) == 1:
        msg = 'Punctuation Key %r (%r)' % (event.keysym, event.char)
    else:
        msg = 'Special Key %r' % event.keysym
    label1.config(text=msg)
 
label1.bind_all('<Key>', key)
 
root.mainloop()

# input a sequence of integer numbers separated by a space and convert to a list
 
def get_integer_list():
    while True:
        # get the sequence string and strip off any trailing space (easy mistake)
        str1 = raw_input("Enter a sequence of integers separated by a space: ").rstrip()
        try:
            # create a list of integers from the string using list comprehension
            return [int(num) for num in str1.split(" ")]
        except ValueError:
            print "Error: '%s' is not an integer! Try again." % num
 
print get_integer_list()

# list the environmental settings of your computer
 
import os
 
keys = os.environ.keys()
keys.sort()
for item in keys:
    print "%-22s : %s" % (item, os.environ[item])

# Get the IP address of the machine this program is running on
# or go to http://www.whatismyip.com/
 
import socket
 
print socket.gethostname()
print socket.getaddrinfo(socket.gethostname(), None)
# get just the IP address from the list's tuple
print socket.getaddrinfo(socket.gethostname(), None)[0][4][0]

# class to convert F to C or C to F
# getFahrenheit(self) would be public
# __getFahrenheit(self) is private
# (double underline prefix makes method private to class)
 
class Temperature (object):
    """allows you to convert Fahrenheit to Celsius and vice versa"""
    def __init__(self):
        self.celsius = 0.0
    def __getFahrenheit(self):
        return 32 + (1.8 * self.celsius)
    def __setFahrenheit(self, f):
        self.celsius = (f - 32) / 1.8
    # property() combines get and set methods into one call
    fahrenheit = property(fget = __getFahrenheit, fset = __setFahrenheit)
 
d = Temperature()
 
# setting celsius value ==> getting fahrenheit value
d.celsius = 25
print "%0.1f C = %0.1f F" % (d.celsius, d.fahrenheit)
 
# setting fahrenheit value and getting celsius value
d.fahrenheit = 98
print "%0.1f F = %0.1f C" % (d.fahrenheit, d.celsius)

def checkInput(type_string, present_value, low, high):
    '''uses a while loop, loops until an acceptible answer is given, then returns it'''
    prompt = "Present %s is %d, enter a new value (%d-%d): " % (type_string, present_value, low, high)
    while True: 
       try:
          a = int(raw_input(prompt))
          if low <= a <= high:
             return a
       except ValueError:
          print "Enter an integer number, please!"
 
 
# modify the present strength of 10 within the range (1-18)
modified_strength = checkInput("strength", 10, 1, 18)
print modified_strength

# using commandline to run a program and files
 
def process_datafile(filename):
    """load specified data file and process data"""
    # code to read file data
    # code to process data and show or return result
    print "Test only, file =", filename   # testing
 
if __name__ == '__main__':
    import sys
 
    # run the progam from the commandline and specify the data file(s) to be loaded
    # something like   myProgram data1.dat data2.dat
    if len(sys.argv) > 1:
        # sys.argv is a list eg. ['C:/Python24/Atest/myProgram.py', 'data1.dat', 'data2.dat']
        # sys.argv[0] is program filename, slice it off with sys.argv[1:]
        # using for loop, more than one datafile can be processed
        for filename in sys.argv[1:]:
            process_datafile(filename)
    else:
        print "usage myProgram datafile1 [datafile2 ...]"