python,python-2.7 , Is there a way to say for every x values, do this?

## Question:

Tag: python,python-2.7

Before I start, I am new to Python, so any low-level description would be incredibly helpful!

I have a list of lets say 60 values (representing one hour, from 8:00-9:00) and I want to run average, maximums, minimums, and standard deviation for each set of 15. (I already have the average, max, mins, and STDEV functions). Is there an understandable way to right this that can be easily scaled to 1,000.000+ values?

The way I am currently doing this does not work and is incredibly inefficient, but I have it posted below:

def for_15(tank_data):
for tank in tank_data:
listfifteen = []
tank_dict = []
count = 0
if count <= 14:
count = count + 1
listfifteen.append(tank_data[tank])
tank_dict['0-14 Avg'] = avg(tank_data[tank])
tank_dict['0-14 Max'] = max(tank_data[tank])
tank_dict['0-14 Min'] = min(tank_data[tank])
tank_dict['0-14 STDEV'] = stdev(tank_data[tank])
listfifteen[tank] = tank_dict
print listfifteen
elif count <= 29:
count = count + 1
listfifteen.append(tank_data[tank])
tank_dict['15-29 Avg'] = avg(tank_data[tank])
tank_dict['15-29 Max'] = max(tank_data[tank])
tank_dict['15-29 Min'] = min(tank_data[tank])
tank_dict['15-29 STDEV'] = stdev(tank_data[tank])
listfifteen[tank] = tank_dict
print listfifteen
elif count <= 44:
count = count + 1
listfifteen.append(tank_data[tank])
tank_dict['30-44 Avg'] = avg(tank_data[tank])
tank_dict['30-44 Max'] = max(tank_data[tank])
tank_dict['30-44 Min'] = min(tank_data[tank])
tank_dict['30-44 STDEV'] = stdev(tank_data[tank])
listfifteen[tank] = tank_dict
print listfifteen
else:
count = count + 1
listfifteen.append(tank_data[tank])
tank_dict['45-59 Avg'] = avg(tank_data[tank])
tank_dict['45-59 Max'] = max(tank_data[tank])
tank_dict['45-59 Min'] = min(tank_data[tank])
tank_dict['45-59 STDEV'] = stdev(tank_data[tank])
listfifteen[tank] = tank_dict
print listfifteen

Thanks!

If you do lst[<start>:<end>] it would give the elements from <start> index (not value) inclusive, to <end> (end index) exclusive.

An example might be able to explain this better -

>>> lst = [1,2,3,4,5,6,7,8,9,10]
>>> lst[0:5]
[1, 2, 3, 4, 5]
>>> lst[5:10]
[6, 7, 8, 9, 10]

Additionally, if you leave, the first <start> part empty, it will by default start from 0 , example -

>>> lst[:6]
[1, 2, 3, 4, 5, 6]

Also, if you leave the last <end> part empty, it will be default go till the last element ( len(list) ) , an example for that -

>>> lst[4:]
[5, 6, 7, 8, 9, 10]

Please note , the [<start>:<end>] notation produces copy of the list, not the orignal list, so if you do any changes to this copy (unless the list contains references and you do changes inside the referenced object) , the changes would not reflect in original list.

Example -

>>> lst
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> newlst = lst[4:]
>>> newlst
[5, 6, 7, 8, 9, 10]
>>> newlst[0] = 1
>>> newlst
[1, 6, 7, 8, 9, 10]
>>> lst
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

# Related:

## How can I resolve my variable's unexpected output?

django,python-2.7
I have a variable in django named optional_message. If I debug the variable then it says Swenskt but when I try to print the variable on my page the following comes out: (u'Swenskt',) and the variable can't be tested for its length etc. What should I do if I only...

## How do I read this list and parse it?

python,list
I'm using requests and the output I get from the sites API is a list, I've been stuck trying to parse it to get the data from it. I use r = requests.get(urlas, params=params) r.json() to get the data I want. Here is a snippet of the list [{'relation_type': None,...

## Twilio Client Python not Working in IOS Browser

I have created a simple twilio client application to make phone calls from Web Browser to phones. I used a sample Flask app to generate a secure Capability Token and used twilio.min.js library to handle calls from my HTML. The functionality works fine in Computer Browsers ans Android Phone Browsers,...

## Replace nodejs for python?

python,node.js,webserver
i'm working in a HTML5 multiplayer game, and i need a server to sync player's movement, chat, battles, etc. So I'm looking for ways to use python instead nodejs, because i have I have more familiarity with python. The server is simple: var express = require('express'); var app = express();...

## Displaying a 32-bit image with NaN values (ImageJ)

python,image-processing,imagej
I wrote a multilanguage 3-D image denoising ImageJ plugin that does some operations on an image and returns the denoised image as a 1-D array. The 1-D array contains NaN values (around the edges). The 1-D array is converted back into an image stack and displayed. It is simply black....

## how to fetch a column in browse_record_list in orm browse method in openERP

python-2.7,orm,openerp-7
I'm beginner in openERP. I'm trying to get a column in a table. While using ORM browse method and iterating that object i got the result in browse_record_list as browse_record(table.name,21). I want to fetch that particular id 21 alone through that browse method but instead im getting same browse_record as...

## group indices of list in list of lists

python,list
I am looking for an elegant solution for the following problem. I have a list of ints and I want to create a list of lists where the indices with the same value are grouped together in the order of the occurrences of said list. [2, 0, 1, 1, 3,...

## Strange Behavior: Floating Point Error after Appending to List

python,python-2.7,behavior
I am writing a simple function to step through a range with floating step size. To keep the output neat, I wrote a function, correct, that corrects the floating point error that is common after an arithmetic operation. That is to say: correct(0.3999999999) outputs 0.4, correct(0.1000000001) outputs 0.1, etc. Here's...

## How to check for multiple attributes in a list

python,python-2.7
I am making a TBRPG game using Python 2.7, and i'm currently making a quest system. I wanted to make a function that checks all of the quests in a list, in this case (quests), and tells you if any of of the quests in the list have the same...

## trying to understand LSH through the sample python code

python,similarity,locality-sensitive-hash
the concise python code i study for is here Question A @ line 8 i do not really understand the syntax meaning for "res = res << 1" for the purpose of "get_signature" Question B @ line 49 (SOLVED BY myself through another Q&A) "xor = r1^r2" does not really...

## Matplotlib: Plot the result of an SQL query

python,sql,matplotlib,plot
from sqlalchemy import create_engine import _mssql from matplotlib import pyplot as plt engine = create_engine('mssql+pymssql://**:****@127.0.0.1:1433/AffectV_Test') connection = engine.connect() result = connection.execute('SELECT Campaign_id, SUM(Count) AS Total_Count FROM Impressions GROUP BY Campaign_id') for row in result: print row connection.close() The above code generates an array: (54ca686d0189607081dbda85', 4174469) (551c21150189601fb08b6b64', 182) (552391ee0189601fb08b6b73', 237304) (5469f3ec0189606b1b25bcc0',...

## represent an index inside a list as x,y in python

python,list,numpy,multidimensional-array
I have a list which contains 1000 integers. The 1000 integers represent 20X50 elements of dimensional array which I read from a file into the list. I need to walk through the list with an indicator in order to find close elements to each other. I want that my indicator...

## Inserting a variable in MongoDB specifying _id field

python,mongodb,pymongo
I want to insert a variable, say, a = {1:2,3:4} into my database with a particular id "56". It is very clear from the docs that I can do the following: db.testcol.insert({"_id": "56", 1:2, 3:4}) However, I cannot figure out any way to insert "a" itself, specifying an id. In...

## Python - Opening and changing large text files

python,replace,out-of-memory,large-files
I have a ~600MB Roblox type .mesh file, which reads like a text file in any text editor. I have the following code below: mesh = open("file.mesh", "r").read() mesh = mesh.replace("[", "{").replace("]", "}").replace("}{", "},{") mesh = "{"+mesh+"}" f = open("p2t.txt", "w") f.write(mesh) It returns: Traceback (most recent call last): File...

## how to enable a entry by clicking a button in Tkinter?

python,tkinter
I need to activate many entries when button is clicked please do not write class based code, modify this code only because i need to change the whole code for the project as i did my whole project without classes from Tkinter import * import ttk x='disabled' def rakhi(): global...

## Sort when values are None or empty strings python

python,list,sorting,null
I have a list with dictionaries in which I sort them on different values. I'm doing it with these lines of code: def orderBy(self, col, dir, objlist): if dir == 'asc': sorted_objects = sorted(objlist, key=lambda k: k[col]) else: sorted_objects = sorted(objlist, key=lambda k: k[col], reverse=True) return sorted_objects Now the problem...

## Python: histogram/ binning data from 2 arrays.

python,histogram,large-files
I have two arrays of data: one is a radius values and the other is a corresponding intensity reading at that intensity: e.g. a small section of the data. First column is radius and the second is the intensities. 29.77036614 0.04464427 29.70281027 0.07771409 29.63523525 0.09424901 29.3639355 1.322793 29.29596385 2.321502 29.22783249...

## The event loop is already running

python,python-3.x,pyqt,pyqt4
I have the following 5 files: gui.py # -*- coding: utf-8 -*- from PyQt4 import QtCore, QtGui try: _fromUtf8 = QtCore.QString.fromUtf8 except AttributeError: def _fromUtf8(s): return s try: _encoding = QtGui.QApplication.UnicodeUTF8 def _translate(context, text, disambig): return QtGui.QApplication.translate(context, text, disambig, _encoding) except AttributeError: def _translate(context, text, disambig): return QtGui.QApplication.translate(context, text, disambig)...

## Python recursive function not recursing

python,recursion
I'm trying to solve a puzzle, which is to reverse engineer this code, to get a list of possible passwords, and from those there should be one that 'stands out', and should work function checkPass(password) { var total = 0; var charlist = "abcdefghijklmnopqrstuvwxyz"; for (var i = 0; i...

## SyntaxError: invalid syntax?

python,syntax
Good afternoon, I am developing a script in python and while I am trying to compile it from the terminator/terminal i always get this error, but I cannot understand where is the syntax error? File "_case1.py", line 128 print ('########################') ^ SyntaxError: invalid syntax Then I just change the position...

## Calling function and passing arguments multiple times

python,function,loops
I want to call the function multiple time and use it's returned argument everytime when it's called. For example: def myfunction(first, second, third): return (first+1,second+1,third+1) 1st call: myfunction(1,2,3) 2nd call is going to be pass returned variables: myfunction(2,3,4) and loop it until defined times. How can I do such loop?...

## Pandas Dataframe Complex Calculation

python,python-2.7,pandas,dataframes
I have the following dataframe,df: Year totalPubs ActualCitations 0 1994 71 191.002034 1 1995 77 2763.911781 2 1996 69 2022.374474 3 1997 78 3393.094951 I want to write code that would do the following: Citations of currentyear / Sum of totalPubs of the two previous years I want something to...

## How does the class_weight parameter in scikit-learn work?

python,scikit-learn
I am having a lot of trouble understanding how the class_weight parameter in scikit-learn's Logistic Regression operates. The Situation I want to use logistic regression to do binary classification on a very unbalanced data set. The classes are labelled 0 (negative) and 1 (positive) and the observed data is in...

## Count function counting only last line of my list

python,python-2.7
Count function counting only last line of my list N = int(raw_input()) cnt = [] for i in range(N): string = raw_input() for j in range(1,len(string)): if string[j] =='K': cnt.append('R') elif string[j] =='R': cnt.append('R') if string[0] == 'k': cnt.append('k') elif string[0] == 'R': cnt.append('R') print cnt.count('R') if I am giving...

## Python Popen - wait vs communicate vs CalledProcessError

python,python-2.7,error-handling,popen
Continuing from my previous question I see that to get the error code of a process I spawned via Popen in python I have to call either wait() or communicate() (which can be used to access the Popen stdout and stderr attributes): app7z = '/path/to/7z.exe' command = [app7z, 'a', dstFile.temp,...

## Spring-integration scripting with Python

python,spring-integration,jython
I'm trying to use Python with spring-integration and jython-standalone-2.7.0: Here is my application context: <int:inbound-channel-adapter id="in" channel="exampleChannel" > <int:poller fixed-rate="1000" /> <int-script:script lang="python" location="script/message.py" /> </int:inbound-channel-adapter> <int:channel id="exampleChannel" /> <int-ip:udp-outbound-channel-adapter id="udpOut" channel="exampleChannel" host="192.168.0.1" port="11111" /> Here is my script in Python: print "Python"...

## Pandas - Dropping multiple empty columns

python,pandas
I have some tables where the first 11 columns are populated with data, but all columns after this are blank. I tried: df=df.dropna(axis=1,how='all') which didn't work. I then used: df = df.drop(df.columns[range(11,36)], axis=1) Which worked on the first few tables, but then some of the tables were longer or shorter...

## Python: can't access newly defined environment variables

python,bash,environment-variables
I can't access my env var: import subprocess, os print os.environ.get('PATH') # Works well print os.environ.get('BONSAI') # doesn't work But the env var is well added in my /home/me/.bashrc: BONSAI=/home/me/Utils/bonsai_v3.2 export BONSAI And I can access this env var from a new terminal....

## odoo v8 - Field(s) `arch` failed against a constraint: Invalid view definition

I want to create a new view with a DB-view. When I try to install my app, DB-view was created then I get error: 2015-06-22 12:59:10,574 11988 ERROR odoo openerp.addons.base.ir.ir_ui_view: Das Feld `datum` existiert nicht Fehler Kontext: Ansicht `overview.tree.view` [view_id: 1532, xml_id: k. A., model: net.time.overview, parent_id: k. A.] 2015-06-22...

## Using counter on array for one value while keeping index of other values

python,collections
After reading the answers on this question How to count the frequency of the elements in a list? I was wondering how to count the frequency of something, and at the same time retreive some extra information, through something like an index. For example a = ['fruit','Item#001'] b = ['fruit','Item#002']...

## Peewee: reducing where conditionals break after a certain length

python,peewee
This is what I have: SomeTable.select.where(reduce(operator.or_, (SomeTable.stuff == entry for entry in big_list))) The problem arises when I have a relatively large list of elements in big_list and I get this: RuntimeError: maximum recursion depth exceeded Is there another way to approach this that doesn't involve splitting up the list...

## Slicing a Python OrderedDict

python-2.7,slice,ordereddictionary
In my code I frequently need to take a subset range of keys+values from a Python OrderedDict (from collections package). Slicing doesn't work (throws TypeError: unhashable type) and the alternative, iterating, is cumbersome: from collections import OrderedDict o = OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4)]) # want to...

## How to change the IP address of Amazon EC2 instance using boto library

python,amazon-web-services,boto
How can I assign a new IP address (or Elastic IP) to an already existing AWS EC2 instance using boto library.

## In sklearn, does a fitted pipeline reapply every transform?

python,scikit-learn,pipeline,feature-selection
Apologies if this is obvious but I couldn't find a clear answer to this: Say I've used a pretty typical pipeline: feat_sel = RandomizedLogisticRegression() clf = RandomForestClassifier() pl = Pipeline([ ('preprocessing', preprocessing.StandardScaler()), ('feature_selection', feat_sel), ('classification', clf)]) pl.fit(X,y) Now when I apply pl on a new set, pl.predict(X_classify); is RandomizedLogisticRegression going...

## How to use template within Django template?

python,html,django,templates,django-1.4
I have the django template like below: <a href="https://example.com/url{{ mylist.0.id }}" target="_blank"><h1 class="title">{{ mylist.0.title }}</h1></a> <p> {{ mylist.0.text|truncatewords:50 }}<br> ... (the actual template is quite big) It should be used 10 times on the same page, but 'external' html elements are different: <div class="row"> <div class="col-md-12 col-lg-12 block block-color-1"> *django...

## How do variables inside python modules work?

python,module,python-module
I am coming from a Java background with Static variables, and I am trying to create a list of commonly used strings in my python application. I understand there are no static variables in python so I have written a module as follows: import os APP_NAME = 'Window Logger' APP_DATA_FOLDER_PATH...

## Identify that a string could be a datetime object

python,regex,algorithm,python-2.7,datetime
If I knew the format in which a string represents date-time information, then I can easily use datetime.datetime.strptime(s, fmt). However, without knowing the format of the string beforehand, would it be possible to determine whether a given string contains something that could be parsed as a datetime object with the...

## What is the difference between <> and == in python?

python-2.7
In [142]: (MON,TUE,WED,THR,FRI,SAT,SUN)<>range(7) Out[142]: True In [143]: (MON,TUE,WED,THR,FRI,SAT,SUN)==range(7) Out[143]: False ...

## Sum of two variables in RobotFramework

python,automated-tests,robotframework
I have two variables: \${calculatedTotalPrice} = 42,42 \${productPrice1} = 43,15 I executed \${calculatedTotalPrice} Evaluate \${calculatedTotalPrice}+\${productPrice1} I got 42,85,15 How can I resolve it?...

## Find the tf-idf score of specific words in documents using sklearn

python,scikit-learn,tf-idf
I have code that runs basic TF-IDF vectorizer on a collection of documents, returning a sparse matrix of D X F where D is the number of documents and F is the number of terms. No problem. But how do I find the TF-IDF score of a specific term in...

## sys.argv in a windows environment

python,windows,python-3.x
I'm attempting to learn python using the book 'a byte of python'. The code: import sys print('the command line arguments are:') for i in sys.argv: print(i) print('\n\nThe PYTHONPATH is', sys.path, '\n') outputs: the command line arguments are: C:/Users/user/PycharmProjects/helloWorld/module_using_sys.py The PYTHONPATH is ['C:\\Users\\user\\PycharmProjects\\helloWorld', 'C:\\Users\\user\\PycharmProjects\\helloWorld', 'C:\\Python34\\python34.zip', 'C:\\Python34\\DLLs', 'C:\\Python34\\lib', 'C:\\Python34', 'C:\\Python34\\lib\\site-packages']...

## SQLAlchemy. 2 different relationships for 1 column

python,sqlalchemy
I have a simple many-to-many relationship with associated table: with following data: matches: users: users_mathces: ONE user can play MANY matches and ONE match can involve up to TWO users I want to realize proper relationships in both "Match" and "User" classes users_matches_table = Table('users_matches', Base.metadata, Column('match_id', Integer, ForeignKey('matches.id', onupdate="CASCADE",...