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How to print only if specific time starts with x in Python

Hi I'm a newbie learning python and I want to print something only if current time starts with x (for example, if current time starts with = 4, print "hi", time = 4:18), this is the code I made, it says attribute error:
import datetime
local = datetime.datetime.now().time().replace(microsecond=0)
if local.startswith('16'):
print("Hi! It's ", local)

The .replace() method returns a date object. date objects don't have a .startswith() method. That method is only for str.
Try converting your date to a string first:
if str(local).startswith('16'):
print("Hi! It's ", local)
The documentation lists all of the methods available on a date object.

You need to first convert it to a string, as datetime objects have no startswith() method. Use strftime, example:
import datetime
t = datetime.datetime(2012, 2, 23, 0, 0)
t2 = t.strftime('%m/%d/%Y')
will yield:
'02/23/2012'. Once it's converted, you can use t2.startswith().
https://docs.python.org/3/library/datetime.html#strftime-strptime-behavior

You can get the hour of the time and check if it is 16:
if local.hour == 16:
print("Hi! It's ",local)
If you need to use startswith() then you can convert it to a string like this:
if str(local).startswith('16'):
print("Hi! It's ", local)

That's not a good way. Check the time as int is the better solution here.
replace() has 2 needed str arguments. You use a named attribute which doesn't exist.

Not able to convert to string

I might be using wrong python terminology.
I have an array of 3 integer elements: month, date and year.
However, I am not able to print each individual element when concatenating strings.
import ssl
import OpenSSL
import time
import sys
def get_SSL_Expiry_Date(host, port):
cert = ssl.get_server_certificate((host, 443))
x509 = OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM, cert)
raw_date = x509.get_notAfter()
decoded_date = raw_date.decode("utf-8")
dexpires = time.strptime(decoded_date, "%Y%m%d%H%M%Sz")
bes = dexpires.tm_mon,dexpires.tm_mday,dexpires.tm_year
print (bes)
#print(bes[0]+"/"+bes[1]+"/"+bes[2])
domain = sys.argv[1]
port = 443
get_SSL_Expiry_Date(domain, port)
If I uncomment line 14, I get an error:
TypeError: unsupported operand type(s) for +: 'int' and 'str'
I am trying to get the date in this format (all strings): Month/Date/Year.
What am I doing wrong?

You can use Python's format() method to handle it (much cleaner also):
print("{0}/{1}/{2}".format(bes[0],bes[1],bes[2]))
...or further simplified (thanks Anton)
print("{0}/{1}/{2}".format(*bes))
↳ Python String Formatting

Simply use:
print(time.strftime("%m/%d/%y",dexpires))
See also https://docs.python.org/3/library/time.html
In general python modules usually contain all kinds of reformatting functions you don't have to reinvent them.
Example:
>>> dexpires=time.strptime('20180823131455z','%Y%m%d%H%M%Sz')
>>> dexpires
time.struct_time(tm_year=2018, tm_mon=8, tm_mday=23, tm_hour=13, tm_min=14, tm_sec=55, tm_wday=3, tm_yday=235, tm_isdst=-1)
>>> time.strftime('%m/%d/%y',dexpires)
'08/23/18'
>>>

First you have to convert int values to string than only you are able to concave them.
You can use str() inbuilt method
print(str(bes[0])+"/"+ str(bes[1])+"/"+ str(bes[2])) #convert int to str first.

Best implementation of dual-side dict in Python

I mean a dictionary where of you could get the value by key or the key by value depending on what you need.

You could use bidict package which provides a bidirectional map. The syntax looks as follows (taken from the documentation):
>>> from bidict import bidict
>>> element_by_symbol = bidict(H='hydrogen')
>>> element_by_symbol
bidict({'H': 'hydrogen'})
>>> element_by_symbol['H']
'hydrogen'
>>> element_by_symbol.inv
bidict({'hydrogen': 'H'})
>>> element_by_symbol.inv['hydrogen']
'H'
>>> element_by_symbol.inv.inv is element_by_symbol
True
Or you can implement it yourself, for example using one of the solutions provided here.

Get a list of subnets matching a given CIDR

I'm trying to take a known subnet ID and CIDR mask, e.g., 10.0.0.0/22, and get a list like this:
[('10.0.0.0', '10.0.3.255'),
('10.0.4.0', '10.0.7.255'),
...
('10.255.252.0', '10.255.255.255')]
I've tried a few existing modules like ipcalc, but it doesn't seem to have a feature like that. I'm not sure what kind of math is necessary for me to write my own module to do it, either.

You can use ipaddress module if you use Python 3.3+:
>>> import ipaddress
>>> it = ipaddress.ip_network('10.0.0.0/8').subnets(new_prefix=22)
>>> networks = [(str(n.network_address), str(n.broadcast_address)) for n in it]
>>> len(networks)
16384
>>> networks[0]
('10.0.0.0', '10.0.3.255')
>>> networks[-1]
('10.255.252.0', '10.255.255.255')
In Python 2.x, use ipaddr:
>>> import ipaddr
>>> it = ipaddr.IPNetwork('10.0.0.0/8').subnet(new_prefix=22)
>>> networks = [(str(n.network), str(n.broadcast)) for n in it]
>>> len(networks)
16384
>>> networks[0]
('10.0.0.0', '10.0.3.255')
>>> networks[-1]
('10.255.252.0', '10.255.255.255')
UPDATE
There's Python 2.7 backport of Python 3.3 ipaddress: py2-ipaddress.

Use the new ipaddress module in Python 3.3:
import ipaddress
for i in ipaddress.ip_network('10.0.0.0/8').subnets(new_prefix=22):
print(i)

how to deserialize a python printed dictionary?

I have python's str dictionary representations in a database as varchars, and I want to retrieve the original python dictionaries
How to have a dictionary again, based in the str representation of a dictionay?
Example
>>> dic = {u'key-a':u'val-a', "key-b":"val-b"}
>>> dicstr = str(dic)
>>> dicstr
"{'key-b': 'val-b', u'key-a': u'val-a'}"
In the example would be turning dicstr back into a usable python dictionary.

Use ast.literal_eval() and for such cases prefer repr() over str(), as str() doesn't guarantee that the string can be converted back to useful object.
In [7]: import ast
In [10]: dic = {u'key-a':u'val-a', "key-b":"val-b"}
In [11]: strs = repr(dic)
In [12]: strs
Out[12]: "{'key-b': 'val-b', u'key-a': u'val-a'}"
In [13]: ast.literal_eval(strs)
Out[13]: {u'key-a': u'val-a', 'key-b': 'val-b'}

You can use eval() or ast.literal_eval(). Most repr() strings can be evaluated back into the original object:
>>> import ast
>>> ast.literal_eval("{'key-b': 'val-b', u'key-a': u'val-a'}")
{'key-b': 'val-b', u'key-a': u'val-a'}

ast.literal_eval could be the way to do it for simple dicts, BUT you should probably rethink your design and NOT save such text in database at first place. e.g.
import collections
d = {'a':1, 'b': collections.defaultdict()}
import ast
print ast.literal_eval(repr(d))
This will not work and throw ValueError('malformed string') basically you won't be convert back dict if it contains any non basic types.
Better way is to dump dict using pickle or json or something like that e.g.
import collections
d = {'a':1, 'b': collections.defaultdict()}
import json
print json.loads(json.dumps(d))
Summary: serialize using repr, deserialize using ast.literal_eval is BAD, serialize using json.dumps and deserialize using json.loads is GOOD