Develop Reference

How to fix "AttributeError: type object has no attribute" in python?

I am adding some code to the preset code to check the time availability, which is if the meeting time can fit into the proposed time schedule. However, I keep getting the following error. Can anyone please give me some advices? Thanks so much for your time.
Preset codes:
from datetime import datetime
class Meeting:
def __init__(self, start_time, end_time):
self.start_time = start_time
self.end_time = end_time
My codes:
def check_availability(meetings, proposed_time):
meeting_start = Meeting.datetime.start_time.hour
meeting_end = Meeting.datetime.end_time.hour
ok_time = datetime.proposed_time.hour
if meeting_start < ok_time < meeting_end:
return True
else:
return False
meetings = [Meeting(datetime(2018, 8, 1, 9, 0, 0), datetime(2018, 8, 1, 11,
0, 0)), Meeting(datetime(2018, 8, 1, 15, 0, 0), datetime(2018, 8, 1, 16, 0,
0)), Meeting(datetime(2018, 8, 2, 9, 0, 0), datetime(2018, 8, 2, 10, 0, 0))]
print(check_availability(meetings, datetime(2018, 8, 1, 12, 0, 0)))
print(check_availability(meetings, datetime(2018, 8, 1, 10, 0, 0)))

Your code raises this exception:
AttributeError: type object 'Meeting' has no attribute 'datetime'
At this line:
meeting_start = Meeting.datetime.start_time.hour
Python is telling you that the Meeting class doesn't have an attribute named datetime. This is true: the Meeting class is a factory for making meeting objects (or instances), and these objects have start_time and end_time attributes, which are set by passing datetime instances to Meeting's __init__ method. These attributes can be accessed like this:
>>> meeting = Meeting(datetime(2018, 8, 1, 9, 0, 0), datetime(2018, 8, 1, 11,
0, 0))
>>> print(meeting.start_time)
2018-08-01 09:00:00
>>> print(meeting.end_time)
2018-08-01 11:00:00
Your check_availability function is being passed a list of meetings, so you need to loop over the list to check whether any of the meetings conflict with the proposed meeting time.
def check_availability(meetings, proposed_time):
# Loop over the list of meetings; "meeting"
# is the meeting that you are currently inspecting.
for meeting in meetings:
# if proposed_time is between meeting.start_time
# and meeting.end_time, return False
# If you get through the list without returning False
# then the proposed time must be ok, so return True.

How to run 'import data'?

I am trying to figure out how to run the script below.
#------------Necessary Variables--------------#
import datetime as dt
symbols = ['INTC','VZ','AAPL', 'AMZN', 'MSFT', 'CAT', 'AXP', 'BA', 'GE', 'CVX', 'HD', 'NKE', 'PFE', 'MMM', 'TRV', 'UTX', 'MRK', 'DIS', 'DWDP', 'JNJ']
allocations = [25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25]
start_date = dt.date(2017, 1, 3)
#Benchmark Index
bench_symbol = "SPY"
#RF Syntax: 6 MO, 2 YR etc.
rate = '1 YR'
rf_start_date = dt.date(2017, 1, 3)
#For Quandl
api_key = "key_here"
#Dirctory Input For Data and Reports
root_path = "C:\\Users\\Excel\\Documents\\Python Scripts"
end_date = dt.date.today()
#------------Run Program----------------------#
if __name__ == '__main__':
#1.) Import the module
import data
#Select Functions
data.portfolio()
data.benchmark()
It almost seems like it is run from some kind of Console window. I've never run any Python code that way before, and that doesn't seem right to me.
The code comes from the link below.
http://programmingforfinance.com/2018/02/tracking-a-portfolio-with-python/

How to use strftime in jalali date in python?

I need convert ''1396/4/28'' to ''1396/04/28'' in persian date.
Code:
from service import jalali
now_date = datetime.datetime.now() // 2017-07-19 21:32:34.574369
date = now_date.strftime('%Y/%m/%d') // 2017-07-19
from_date = jalali.Gregorian(date).persian_string("{}/{}/{}") // '1396/4/28'
How to convert ''1396/4/28'' to ''1396/04/28'' in persian date in python ?

With strptime:
from datetime import datetime
from service import jalali
from_date = jalali.Gregorian(date).persian_string("{}/{}/{}")
print datetime.strptime('1396/4/28', '%Y/%m/%d')
print datetime.strptime(from_date, '%Y/%m/%d')
> datetime.datetime(1396, 4, 28, 0, 0)
> datetime.datetime(1396, 4, 28, 0, 0)
If you mean how to print a date like this with strftime - that is not possible for dates <1900. Print it manually instead:
print ("%04d/%02d/%02d" % (date.year, date.month, date.day))
> 1396/04/28

You can use PersianTools:
from persiantools.jdatetime import JalaliDateTime
import datetime
now_date = datetime.datetime.now() # datetime.datetime(2021, 2, 11, 15, 1, 57, 256596)
from_date = JalaliDateTime.to_jalali(now_date) # JalaliDateTime(1399, 11, 23, 15, 1, 57, 256596)
from_date.strftime("%Y/%m/%d") # '1399/11/23'

Turning list of lists into objects

I currently have a list of lists where every list consists of the same kind of information, say:
[['Planet Name', 16, 19, 27, 11], ['Planet Name 2', 12, 22, 11, 42], ....]
and I would like to use a class to make this into a list of objects with the same information, where index 0 is self.name, index 1 is self.distance and so on for every seperate list.
I know that I need to use some kind of a for loop, but have no idea how to go about and do this.
I would really appreciate some help, trying to learn Python and currently classes!

You can use namedtuple like this, to create an object dynamically, with the list of field names. *item in this code is called, unpacking of arguments list
from collections import namedtuple
Planet = namedtuple("Planet", ["name", "distance", "a", "b", "c"])
data = [['Planet Name', 16, 19, 27, 11],['Planet Name 2', 12, 22, 11, 42]]
for item in data:
planet = Planet(*item)
print planet.name, planet.distance, planet
Output
Planet Name 16 Planet(name='Planet Name', distance=16, a=19, b=27, c=11)
Planet Name 2 12 Planet(name='Planet Name 2', distance=12, a=22, b=11, c=42)
Note: namedtuple is a subclass of tuple. So, all the objects created with namedtuple are immutable. It means that, once the object is created, data in the member variables cannot be changed.

Well... To make a class like you want you can do something like this:
class Planet(object):
def __init__(self, *args, **kwargs):
self.name = args[0]
self.distance = args[1]
# ... etc ...
Or something like this:
class Planet(object):
def __init__(self, name, distance, ...):
self.name = name
self.distance = distance
# ... etc ...
And then you call it like this:
p = Planet(*['Planet Name', 16, 19, 27, 11])
In a loop that would be:
l = [['Planet Name', 16, 19, 27, 11], ['Planet Name 2', 12, 22, 11, 42], ....]
planets = [Planet(*data) for data in l]

I'm confused. Have you created the Planet constructor yet?
The code would be something like:
class Planet(object):
def __init__(self, ....):
....
planets = [['Planet Name', 16, 19, 27, 11]['Planet Name 2', 12, 22, 11, 42]....]
planet_list = [Planet(*p) for p in planets]

If you don't want to have a constructor (__init__) which knows about the specifics of your lists, you could do it like this
lists = [['Planet Name', 16, 19, 27, 11], ['Planet Name 2', 12, 22, 11, 42]]
class Planet(object):
pass
for l in lists:
planet = Planet()
setattr(planet, 'name', l[0])
setattr(planet, 'distance', l[1])
setattr(planet, 'size', l[2])
print planet.name, planet.distance, planet.size

how to store and access datetime(s) in a Python object that needs to be converted into JSON?

I'm working on my first python script, which creates and updates and object with different datetime entries.
I'm setting up the object like this:
# Date conversion
import datetime
import time
# 0:01:00 and 0:00:00 threshold and totalseconds
threshold = time.strptime('00:01:00,000'.split(',')[0],'%H:%M:%S')
tick = datetime.timedelta(hours=threshold.tm_hour,minutes=threshold.tm_min,seconds=threshold.tm_sec).total_seconds()
zero_time = datetime.timedelta(hours=0,minutes=0,seconds=0)
zero_tick = zero_time.total_seconds()
format_date = '%d/%b/%Y:%H:%M:%S'
from datetime import datetime
# Response object
class ResponseObject(object):
def __init__(self, dict):
self.__dict__ = dict
# JSON encoding
from json import JSONEncoder
class MyEncoder(JSONEncoder):
def default(self, o):
return o.__dict__
# > check for JSON response object
try:
obj
except NameError:
obj = ResponseObject({})
...
entry = "14/Nov/2012:09:32:31 +0100"
entry_tz = str.join(' ', entry.split(None)[1:6])
entry_notz = entry.replace(' '+entry_tz,'')
this_time = datetime.strptime(entry_notz, format_date)
# > add machine to object if not there, add init time
if not hasattr(obj, "SOFTINST"):
#line-breaks for readability
setattr(obj, "SOFTINST", {
"init":this_time,
"last":this_time,
"downtime":zero_time,
"totaltime":"",
"percentile":100
})
...
print this_time
print MyEncoder().encode({"hello":"bar"})
print getattr(obj, "SOFTINST")
My last 'print' returns this:
{
'totaltime': datetime.timedelta(0),
'uptime': '',
'last': datetime.datetime(2012, 11, 14, 9, 32, 31),
'init': datetime.datetime(2012, 11, 14, 9, 32, 31),
'percentile': 100,
'downtime': 0
}
Which I cannot convert into JSON...
I don't understand why this:
print this_time #2012-11-14 09:32:31
but inside the object, it's stored as
datetime.datetime(2012, 11, 14, 9, 32, 31)
Question:
How do I store datetime objects in "string format" and still have them easily accessible (and modifyable) in Python?
Thanks!

Use the isoformat method on the datetime object. (see reference: http://docs.python.org/release/2.5.2/lib/datetime-datetime.html)