10 Things I Love About Tech- Python Edition

So since I already complained about what I hate about tech from a diversity and culture perspective, I felt I needed to explain all the things I love about tech and why I wouldn’t want to be anywhere else.

Everyone would expect me to start with databases or virtualization, but I thought I’d keep everyone on their toes and start with my favorite programming language- PYTHON!

1.Timed Pauses, Stops and Waits

Sometimes systems are just too fast for humans.  It’s important to have proper delays between tasks so that people are able to interact or systems are able to respond to each other in the proper amount of time.  This is where the “sleep” command comes in.  Just like in Bash shell, sleep is used to tell a command to wait:

@logged("%b %d %Y - %H:%M:%S")
def add2(x, y):
    time.sleep(2)
    return x + y

The command above translates to “Time to sleep [in seconds] and then proceed with the next command[s].”  This comes in handy as you time out spaces between tasks and is a common command you’ll see in any python program.

2. Context Managers

The ability to write to files or create scripts dynamically is an important one in any programming language.  We write and append to files as needed and this is something we can do with Python using context management.  Simply open a file, write to it and then remember to close it afterwards, (which I didn’t add

>>>file = open(“/var/testfile.txt”,”w”) 
 
>>>file.write(“#Fix File Script”) 
>>>file.write(“mv /var/testfile.txt /usr/mvfile.sh”) 
>>>file.write(“chmod 774 /var/testfile.txt”) 
>>>file.write(“exit”) 
 
>>>file.close()

3.  Generators

As DBAs, we understand the value of a sequence.  We use them all the time in databases and create them with the simple command:

CREATE SEQUENCE emp_seq
 START WITH     1
 INCREMENT BY   1;

In programming languages, often its just as easy and with Python, we’re able to do all kinds of tasks via a function in a sequential manner.  There are distinct requirements to use a generator, but one of them is to use the word yield, as each function call must yield a value of some sort.

>>> def f():
...   print("-- Ready --")
...   yield 1
...   print("-- Set --")
...   yield 2
...   print("-- Go --")
...   yield 3
>>> gen = f()
>>> next(gen)
-- Ready --
1
>>> next(gen)
-- Set --
2
>>> next(gen)
-- Go --
3

Each of the yield values are stored in the object created by this function.  As you can see, this could be a bit cumbersome, so how can we do it in a simpler manner with Python?

4.  Iterators

Another way to perform something sequentially and simply, is to use an iterator.  While the iterator can save us a lot of time by building out from a list-

>>> f = [1, 2, 3]  
>>> iter(f)
<...iterator object at ...>
>>> f.__iter__()

We can save even more time by using a file as an iterator.  Yes, you heard me-  The file is the iterator and at no time does it create a separate object.  Keep in mind, only sequential access with a single thread is allowed here, too.

>>> f = open('/home/python/dbakevlar/file.txt')
>>> f is f.__iter__()
True

>>> local = [80031, 80204, 80221] 
>>> "Westminster","Denver","Aurora" = local

>>> Westminster
80031 
>>> Denver
80204
>>> Aurora
80221

from inspect import getargspec as gas   

def decorate(fn):
    argspec = gas(fn)
    scd_argname = argspec[0][1]
    def inner(*args, **kwargs):
        special_value = (kwargs[scd_argname] 
                         if scd_argname in kwargs else args[1])
        if special_value == 2:
            print "nada"
        else:
            print "nada happening"
        return fn(*args, **kwargs)
    return inner

@decorate
def nada(a, b, c=3):
    pass

nada(1,2,3)
nada(1,b=2,c=4)
nada(1,3,5)
nada(1,b=6,c=5)

>>> a, *rest, b = range(10) 
>>> a 
0
>>> b 
9 
>>> rest [1, 2, 3, 4, 5, 6, 7, 8]

>>> *rest, b = range(10) 
>> rest 
[0, 1, 2, 3, 4, 5, 6, 7, 8] 
>>> b 
9

>>> Geocode = "80031" 

>>> print a[::-1] 

13008

print("The %(foo)s is %(bar)i." % {'foo': 'answer', 'bar':42})

math.gcd(a)

math.isfinite(b)

min(a), max(b)