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Python: How can I append without overriding past append for loop

I am currently trying to append to the output list in my code the id of the query result. I can get it to do one of the ids but it will override the first one how can I change my code to allow any amount of looping to the output.append(q.id)
Here is the code:
#app.route('/new-mealplan', methods=['POST'])
def create_mealplan():
data = request.get_json()
recipes = data['recipes']
output = []
for recipe in recipes:
try:
query = Recipes.query.filter(func.lower(Recipes.recipe_name) == func.lower(recipe)).all()
# print(recipe)
if query:
query = Recipes.query.filter(func.lower(Recipes.recipe_name) == func.lower(recipe)).all()
for q in query:
output.append(q.id)
finally:
return jsonify({"data" : output})

To fix this I removed the
Try and Finally blocks.
Then returned after the for-loop was completed.

Python Google Calendar sort by date

I've got a script that grabs every event off of a Google Claendar, and the searches through those events, and prints the ones that contain a search term to a file.
The problem I'm having is that I need them to be put in order by date, and this doesn't seem to do that.
while True:
events = calendar_acc.events().list(calendarId='myCal',pageToken=page_token).execute()
for event in events['items']:
if 'Search Term' in event['summary']:
#assign names to hit, and date
find = event['summary']
date = event['start'][u'dateTime']
#only print the first ten digits of the date.
month = date[5:7]
day = date[8:10]
year = date[0:4]
formatted_date = month+"/"+day+"/"+year
#write a line
messy.write(formatted_date+" "+event['summary']+"\n\n")
I think there is a way to do this with the time module maybe, but I'm not sure. Any help is appreciated.

Just in case anyone else needs to do this. With the help of jedwards.
I ended up creating an empty list: hits
And then appending the ['start']['dateTime'] as an datetime.datetime object,
and ['summary'] to the list for each event that contained my "Search Term". Like so:
hits = []
while True:
events = calendar_acc.events().list(calendarId='My_Calendar_ID', pageToken=page_token).execute()
for event in events['items']:
if "Search Term" in event['summary']:
hits.append((dateutil.parser.parse(event['start']['dateTime']), event['summary']))
page_token = events.get('nextPageToken')
if not page_token:
break
The you just sort the list, and in my case, I cut the datetime object down to just be the date. And then wrote the whole line to a file. But this code just prints it to the console.
hits.sort()
for x in hits:
d = x[0]
date = "%d/%d/%d"%(getattr(d,'month'),getattr(d,'day'), getattr(d,'year'))
final = str(date)+"\t\t"+str(x[1])
print final
Thanks again to jedwards in the comments!

You can return a sorted list (by date ascending) from the API by using the "orderBy" parameter and setting it to "updated".
page_token = None
while True:
events = service.events().list(calendarId=myID, orderBy='updated', pageToken=page_token).execute()
for event in events['items']:
print(event)
page_token = events.get('nextPageToken')
if not page_token:
break
For more information see: https://developers.google.com/calendar/v3/reference/events/list
Hope this helps.

not able to undertand cursors in appengine

I'm trying to fetch results in a python2.7 appengine app using cursors, but each time I use with_cursor() it fetches the same result set.
query = Model.all().filter("profile =", p_key).order('-created')
if r.get('cursor'):
query = query.with_cursor(start_cursor = r.get('cursor'))
cursor = query.cursor()
objs = query.fetch(limit=10)
count = len(objs)
for obj in objs:
...
Each time through I'm getting same 10 results. I'm thinkng it has to do with using end_cursor, but how do I get that value if query.cursor() is returning the start_cursor. I've looked through the docs but this is poorly documented.

Your formatting is a bit screwy by the way. Looking at your code (which is incomplete and therefore potentially leaving something out.) I have to assume you have forgotten to store the cursor after fetching results (or return to the user - I am assuming r is a request ?).
So after you have fetched some data you need to call cursor() on the query. e.g This function counts all entities using a cursor.
def count_entities(kind):
c = None
count = 0
q = kind.all(keys_only=True)
while True:
if c:
q.with_cursor(c)
i = q.fetch(1000)
count = count + len(i)
if not i:
break
c = q.cursor()
return count
See how after fetch() has been called the c=q.cursor() call and it's is used as the cursor next time through the loop.

Here's what finally worked:
query = Model.all().filter("profile =", p_key).order('-created')
if request.get('cursor'):
query = query.with_cursor(request.get('cursor'))
objs = query.fetch(limit=10)
cursor = query.cursor()
for obj in objs:
...

Limit calls to external database with Python CGI

I've got a Python CGI script that pulls data from a GPS service; I'd like this information to be updated on the webpage about once every 10s (the max allowed by the GPS service's TOS). But there could be, say, 100 users viewing the webpage at once, all calling the script.
I think the users' scripts need to grab data from a buffer page that itself only upates once every ten seconds. How can I make this buffer page auto-update if there's no one directly viewing the content (and not accessing the CGI)? Are there better ways to accomplish this?

Cache the results of your GPS data query in a file or database (sqlite) along with a datetime.
You can then do a datetime check against the last cached datetime to initiate another GPS data query.
You'll probably run into concurrency issues with cgi and the datetime check though...
To get around concurrency issues, you can use sqlite, and put the write in a try/except.
Here's a sample cache implementation using sqlite.
import datetime
import sqlite3
class GpsCache(object):
db_path = 'gps_cache.db'
def __init__(self):
self.con = sqlite3.connect(self.db_path)
self.cur = self.con.cursor()
def _get_period(self, dt=None):
'''normalize time to 15 minute periods'''
if dt.minute < 15:
minute_period = 0
elif 15 <= dt.minute < 30:
minute_period = 15
elif 30 <= dt_minute < 45:
minute_period = 30
elif 45 <= dt_minute:
minute_period = 25
period_dt = datetime.datetime(year=dt.year, month=dt.month, day=dt.day, hour=dt.hour, minute=minute_period)
return period_dt
def get_cache(dt=None):
period_dt = self._get_period(dt)
select_sql = 'SELECT * FROM GPS_CACHE WHERE date_time = "%s";' % period_dt.strftime('%Y-%m-%d %H:%M')
self.cur.execut(select_sql)
result = self.cur.fetchone()[0]
return result
def put_cache(dt=None, data=None):
period_dt = self._get_period(dt)
insert_sql = 'INSERT ....' # edit to your table structure
try:
self.cur.execute(insert_sql)
self.con.commit()
except sqlite3.OperationalError:
# assume db is being updated by another process with the current resutls and ignore
pass
So we have the cache tool now the implementation side.
You'll want to check the cache first then if it's not 'fresh' (doens't return anything), go grab the data using your current method. Then cache the data you grabbed.
you should probably organize this better, but you should get the general idea here.
Using this sample, you just replace your current calls to 'remote_get_gps_data' with 'get_gps_data'.
from gps_cacher import GpsCache
def remote_get_gps_data():
# your function here
return data
def get_gps_data():
data = None
gps_cache = GpsCache()
current_dt = datetime.datetime.now()
cached_data = gps_cache.get_cache(current_dt)
if cached_data:
data = cached_data
else:
data = remote_get_gps_data()
gps_cache.put_cache(current_dt, data)
return data

What is an efficient way of inserting thousands of records into an SQLite table using Django?

I have to insert 8000+ records into a SQLite database using Django's ORM. This operation needs to be run as a cronjob about once per minute.
At the moment I'm using a for loop to iterate through all the items and then insert them one by one.
Example:
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
What is an efficient way of doing this?
Edit: A little comparison between the two insertion methods.
Without commit_manually decorator (11245 records):
nox#noxdevel marinetraffic]$ time python manage.py insrec
real 1m50.288s
user 0m6.710s
sys 0m23.445s
Using commit_manually decorator (11245 records):
[nox#noxdevel marinetraffic]$ time python manage.py insrec
real 0m18.464s
user 0m5.433s
sys 0m10.163s
Note: The test script also does some other operations besides inserting into the database (downloads a ZIP file, extracts an XML file from the ZIP archive, parses the XML file) so the time needed for execution does not necessarily represent the time needed to insert the records.

You want to check out django.db.transaction.commit_manually.
http://docs.djangoproject.com/en/dev/topics/db/transactions/#django-db-transaction-commit-manually
So it would be something like:
from django.db import transaction
#transaction.commit_manually
def viewfunc(request):
...
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
transaction.commit()
Which will only commit once, instead at each save().
In django 1.3 context managers were introduced.
So now you can use transaction.commit_on_success() in a similar way:
from django.db import transaction
def viewfunc(request):
...
with transaction.commit_on_success():
for item in items:
entry = Entry(a1=item.a1, a2=item.a2)
entry.save()
In django 1.4, bulk_create was added, allowing you to create lists of your model objects and then commit them all at once.
NOTE the save method will not be called when using bulk create.
>>> Entry.objects.bulk_create([
... Entry(headline="Django 1.0 Released"),
... Entry(headline="Django 1.1 Announced"),
... Entry(headline="Breaking: Django is awesome")
... ])
In django 1.6, transaction.atomic was introduced, intended to replace now legacy functions commit_on_success and commit_manually.
from the django documentation on atomic:
atomic is usable both as a decorator:
from django.db import transaction
#transaction.atomic
def viewfunc(request):
# This code executes inside a transaction.
do_stuff()
and as a context manager:
from django.db import transaction
def viewfunc(request):
# This code executes in autocommit mode (Django's default).
do_stuff()
with transaction.atomic():
# This code executes inside a transaction.
do_more_stuff()

Bulk creation is available in Django 1.4:
https://django.readthedocs.io/en/1.4/ref/models/querysets.html#bulk-create

Have a look at this. It's meant for use out-of-the-box with MySQL only, but there are pointers on what to do for other databases.

You might be better off bulk-loading the items - prepare a file and use a bulk load tool. This will be vastly more efficient than 8000 individual inserts.

To answer the question particularly with regard to SQLite, as asked, while I have just now confirmed that bulk_create does provide a tremendous speedup there is a limitation with SQLite: "The default is to create all objects in one batch, except for SQLite where the default is such that at maximum 999 variables per query is used."
The quoted stuff is from the docs--- A-IV provided a link.
What I have to add is that this djangosnippets entry by alpar also seems to be working for me. It's a little wrapper that breaks the big batch that you want to process into smaller batches, managing the 999 variables limit.

You should check out DSE. I wrote DSE to solve these kinds of problems ( massive insert or updates ). Using the django orm is a dead-end, you got to do it in plain SQL and DSE takes care of much of that for you.
Thomas

def order(request):
if request.method=="GET":
cust_name = request.GET.get('cust_name', '')
cust_cont = request.GET.get('cust_cont', '')
pincode = request.GET.get('pincode', '')
city_name = request.GET.get('city_name', '')
state = request.GET.get('state', '')
contry = request.GET.get('contry', '')
gender = request.GET.get('gender', '')
paid_amt = request.GET.get('paid_amt', '')
due_amt = request.GET.get('due_amt', '')
order_date = request.GET.get('order_date', '')
print(order_date)
prod_name = request.GET.getlist('prod_name[]', '')
prod_qty = request.GET.getlist('prod_qty[]', '')
prod_price = request.GET.getlist('prod_price[]', '')
print(prod_name)
print(prod_qty)
print(prod_price)
# insert customer information into customer table
try:
# Insert Data into customer table
cust_tab = Customer(customer_name=cust_name, customer_contact=cust_cont, gender=gender, city_name=city_name, pincode=pincode, state_name=state, contry_name=contry)
cust_tab.save()
# Retrive Id from customer table
custo_id = Customer.objects.values_list('customer_id').last() #It is return
Tuple as result from Queryset
custo_id = int(custo_id[0]) #It is convert the Tuple in INT
# Insert Data into Order table
order_tab = Orders(order_date=order_date, paid_amt=paid_amt, due_amt=due_amt, customer_id=custo_id)
order_tab.save()
# Insert Data into Products table
# insert multiple data at a one time from djanog using while loop
i=0
while(i<len(prod_name)):
p_n = prod_name[i]
p_q = prod_qty[i]
p_p = prod_price[i]
# this is checking the variable, if variable is null so fill the varable value in database
if p_n != "" and p_q != "" and p_p != "":
prod_tab = Products(product_name=p_n, product_qty=p_q, product_price=p_p, customer_id=custo_id)
prod_tab.save()
i=i+1

I recommend using plain SQL (not ORM) you can insert multiple rows with a single insert:
insert into A select from B;
The select from B portion of your sql could be as complicated as you want it to get as long as the results match the columns in table A and there are no constraint conflicts.

def order(request):
if request.method=="GET":
# get the value from html page
cust_name = request.GET.get('cust_name', '')
cust_cont = request.GET.get('cust_cont', '')
pincode = request.GET.get('pincode', '')
city_name = request.GET.get('city_name', '')
state = request.GET.get('state', '')
contry = request.GET.get('contry', '')
gender = request.GET.get('gender', '')
paid_amt = request.GET.get('paid_amt', '')
due_amt = request.GET.get('due_amt', '')
order_date = request.GET.get('order_date', '')
prod_name = request.GET.getlist('prod_name[]', '')
prod_qty = request.GET.getlist('prod_qty[]', '')
prod_price = request.GET.getlist('prod_price[]', '')
# insert customer information into customer table
try:
# Insert Data into customer table
cust_tab = Customer(customer_name=cust_name, customer_contact=cust_cont, gender=gender, city_name=city_name, pincode=pincode, state_name=state, contry_name=contry)
cust_tab.save()
# Retrive Id from customer table
custo_id = Customer.objects.values_list('customer_id').last() #It is return Tuple as result from Queryset
custo_id = int(custo_id[0]) #It is convert the Tuple in INT
# Insert Data into Order table
order_tab = Orders(order_date=order_date, paid_amt=paid_amt, due_amt=due_amt, customer_id=custo_id)
order_tab.save()
# Insert Data into Products table
# insert multiple data at a one time from djanog using while loop
i=0
while(i<len(prod_name)):
p_n = prod_name[i]
p_q = prod_qty[i]
p_p = prod_price[i]
# this is checking the variable, if variable is null so fill the varable value in database
if p_n != "" and p_q != "" and p_p != "":
prod_tab = Products(product_name=p_n, product_qty=p_q, product_price=p_p, customer_id=custo_id)
prod_tab.save()
i=i+1
return HttpResponse('Your Record Has been Saved')
except Exception as e:
return HttpResponse(e)
return render(request, 'invoice_system/order.html')