#acl AdminGroup:read,write,delete,revert  EditorGroup:read,write StudentGroup:read,write All:read
#format wiki
#language de
#pragma section-numbers off

== Logical expressions, modules ==

Program the xor function corresponding to the following table

||'''A'''||'''B'''||'''A xor B'''||
||False  ||  False||  False ||
||False  ||  True ||  True  ||
||True   ||  False||  True  ||
||True   ||  True ||  False ||

Use the operations {{{and, or, not}}} and brackets {{{()}}}.

Help: use the following code {{{logic.py}}} and add the term in {{{...}}} in line 5

{{{
# Module logic.py

def xor(A,B):
    """Returns the logical exclusive or of A and B"""
    C=((A or B ) and   (not(A and B)))
    return C

if __name__=='__main__': # if the module is not imported
    # but started with run, the following lines will be executed

    K=((False,False),(False,True),(True,False),(True,True))
    print 'A\tB\tA xor B'
    for k in K:
        A,B=k[0],k[1]
        print A,'\t',B,'\t',xor(A,B)
}}}

Open a file with an editor of your choice (I recommend xemacs or nedit) and save the file as {{{logic.py}}}. 
Use tabs not blanks.

Start ipython and {{{run}}} your program 
{{{
In [1]: from logic import xor
In [2]: xor(False,False)
Out[2]: False
In [3]: xor(True,False)
Out[3]: True
In [4]: run xor
A B A xor B
False False False
False True True
True False True
True True False
In [5]: help(xor)
In [1]: from scipy import logical_xor
In [2]: logical_xor(True,True)
Out[2]: False
}}}

[[/Solution_XOR]]
== Dictionaries ==
Program a date function that returns the number of the month (integer) for a given month (string).

Use the string methods {{{.upper()}}} or {{{.lower()}}} to account for capitalization.


[[/Solution_date]]
== Range ==
What is the corresponding {{{range()}}} expression for the following lists?
{{{
[1, 3, 5, 7, 9]
[5, 8, 11, 14, 17]
[19, 18, 17, 16, 15, 14, 13]
}}}

=== Solution ===
{{{
range(1,10,2)
b=range(5,18,3)
c=range(19,12,-1)
}}}

== Lists and Strings ==

Write a program that reads in a textfile and sorts its words in order of the frequency of occurence.

Help: read in a textfile in a string
{{{
s=file(’test.txt’).read()
}}}

The method {{{.split(arg)}}} cuts the string in a list. The method {{{.count(arg)}}} calculates the frequency of occurence.
The method {{{.sort()}}} sorts (in place).

[[/Solution]]
== Modules ==

Which subpackages are included in the scipy module?

[[/Solution_modules]]