Re: [Tutor] PI
On 05/25/2011 09:21 PM, David Merrick wrote: How do I can access to the math module to use PI? area = math.pi * pow(3,2) Traceback (most recent call last): File "", line 1, in area = math.i * pow(3,2) NameError: name 'math' is not defined try 'import math' first... ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Better way to compare values?
Hello,
Recently picked back up the Python bug, and have started chipping away
at the warm-up exercises over @ codingbat.com.
I'm getting thru the basic stuff okay, but I'm getting a feeling that
maybe I'm not doing things the 'right' way, even though the results are
correct.
Specifically, checking if value 'a' OR value 'b' equal a certain number...
The example that I'm on at the moment (like I said, starting over at the
basics)...
http://codingbat.com/prob/p124984
My solution:
'''
Given 2 ints, a and b, return True if one if them is 10 or if their sum
is 10.
makes10(9, 10) = True
makes10(9, 9) = False
makes10(1, 9) = True
'''
def makes10(a, b):
if (a == 10) or (b == 10):
#print('Yep!')
return(True)
elif a + b == 10:
#print('Si!')
return(True)
else:
#print('Nein!')
return(False)
makes10(10,9)
#makes10(9,9)
#makes10(1,9)
In particular, the 'if (a == 10) or (b == 10): line... is there a
shorter/more compact/more correct (i.e. pythonic) way of testing to see
if a OR b is equal to 10?
Thanks,
Monte
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Re: [Tutor] Better way to compare values?
There's a few things that can make this a lot shorter. To address your primary question first, the python idiom for this is like so: if 10 in (a, b): it constructs a tuple containing the variables a and b, then checks if the number ten is inside that tuple. simple and straightforward. Now, or's aren't limited to just two operands. you can chain multiple or's together to make this function even shorter, like so: if a == 10 or b == 10 or a + b == 10: That's pretty much what the 'book' solution was (found the 'Show Solution' button staring me in the face shortly after posting my question here. def makes10(a,b) return(a == 10 or b == 10 or a + b == 10) So, all said and done, the solution to your problem in idiomatic python looks like this: def makes10(a, b): return 10 in (a, b, a + b) Something else I learned from this... for some reason I had the idea in my head that 'return' was a function like print() i.e. 'return()'. Obviously not, from your example and from others that I dug up in the Python docs. Thanks for the detailed explanation - it was very clear and easy to follow! What I had originally been thinking was something like 'a && b' or 'a || b'... but that was probably some cross-pollenation from earlier dabbling in PHP or something ;) Thanks, Monte ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] ?!
On 04/21/2015 04:17 AM, Ryan Scholes wrote: Hi, Didn't really understand the instructions on the website but is this the right email address for help? It can be... Some very smart, experienced and helpful folks here - some are even all three! ;) Generally speaking... they aren't going to do your (home) work for you... try to provide some code to show what you've tried, and specific questions as to what you're having trouble with. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] https://trinket.io
On 05/21/2015 01:02 AM, Albert-Jan Roskam via Tutor wrote: Not sure whether I like this better than IPython Notebook, though. I was given to understand that the target use / demographic was a bit different than with iPython... Monte -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] question / decision tree
On 08/03/2015 02:38 AM, matej taferner wrote: Or maybe should I go with the tkinter? As a final product of this decision tree "app" I need a clickable buttons ready to be embedded into the website which will guide customer(s) to desired answer(s). The two aren't exactly compatible. Tkinter is for stand-alone desktop applications. While they can run a call to open a browser to an appropriate web page, if everything else is already on the web site it seems like it would make sense to do the front-end the same way, rather than have to deploy a separate application. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Run Python 2.7 on Android Tablet
On 11/10/2015 01:32 PM, Laura Creighton wrote: In a message of Tue, 10 Nov 2015 12:38:27 -0500, "Ken Hammer" writes: My MIT OCW 6.00SC course is installed on a Windows 8.1 desktop machine. I'd like to study and explore away from my office and desk on my tablet running Android 4.2.2. Possible? thanks, Ken Yes. use Python Anywhere in a browser on your tablet. https://www.pythonanywhere.com/ https://mail.python.org/mailman/listinfo/tutor Or koding.io... but PythonAnywhere is nicer for straight-up python. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] flask/sqlite3 problem - 'OperationalError: no such table'?
Hello there,
I'm working thru a Flask tutorial, and when I get to the portion for
querying the database (sqlite3) for the existing posts, i.e. 'SELECT *
FROM posts', I get an error that says there is no such table 'posts' in
my database. Yet I can query said db file from either the sqlite3
command-line client, or from the python interactive interpreter, and run
the same query and get the expected results. I've looked at this 'til
I'm about ready to go cross-eyed... I'm sure it must be something simple
that I'm missing, but I can't seem to spot it. Below is the tail end of
the traceback error message, followed by the code from the file in
question. Any help would be much appreciated.
Thanks,
Monte
Traceback (most recent call last):
...
return test(*args, **kwargs)
File
"/home/monte/Dropbox/Documents/Programming/python/flask/blog/blog.py",
line 57, in main
cur = g.db.execute('SELECT * FROM posts')
OperationalError: no such table: posts
# blog.py - application module
from flask import Flask, render_template, request, session, flash,
redirect, url_for, g
from functools import wraps
import sqlite3
# Configuration
DATABASE = 'fblog.db'
USERNAME = 'admin'
PASSWORD = 'admin'
SECRET_KEY = 'hard to guess'
app = Flask(__name__)
app.config.from_object(__name__)
def connect_db():
#return sqlite3.connect(app.config['DATABASE'])
return sqlite3.connect('fblog.db')
Other functions not shown for brevity
@app.route('/main')
@login_required
def main():
g.db = connect_db()
cur = g.db.execute('SELECT * FROM posts')
posts = [dict(title=row[0], post=row[1]) for row in cur.fetchall()]
g.db.close()
return render_template('main.html', posts=posts)
if __name__ == '__main__':
app.run(debug=True)
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Re: [Tutor] flask/sqlite3 problem - 'OperationalError: no such table'?
Sheeesh... After reading your message, I realized I was running the script from inside a new-to-me IDE (pycharm), and started wondering if somehow a path or working directory was not what I thought it might be. I closed out the IDE window, and ran the script directly from the terminal - success! After that I went thru and did some digging through the settings for this particular 'project' in pycharm, and found an option for the working directory, which was set to a different folder. I fixed that and everything is off and running again. Looks like I need to do some more reading up on projects in pycharm before I shoot myself in the foot again... Thanks, Monte ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What are your favourite unofficial resources
On 06/29/2014 03:41 PM, Alan Gauld wrote: I'm looking for tips for an appendix to a book that I'm working on. What are the best unofficial (ie not python.org) resources for people who have learned the basics but are not experts yet? ie Typical tutor list "graduates"... I'm thinking about web sites, blogs, books, videos etc. Anything that might be worth knowing about. I've got a few of my own - Activestate, O'Reilly, ByteOfPython, PythonChallenge, ShowMeDo etc. But I thought the tutor list readers might be an interesting source of alternatives that I hadn't thought of, or even heard of. All contributions considered :-) Some stuff that I've bookmarked over time... not all of which I've actually go around to making use of :( http://interactivepython.org/courselib/static/pythonds/index.html http://rosettacode.org/wiki/Rosetta_Code http://rosalind.info/problems/locations/ http://nullege.com/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Why is Quick Search at docs.Python.org so useless?
On 07/05/2014 11:53 AM, Mark Lawrence wrote: As I said it's a known problem, but then so are the 4600 bugs at bugs.python.org. So why bother spending the time making the search useful when there is a well known workaround Because it's supposed to be the first place new (and old) users go to find their answers. Because the work-around isn't published right *there* where people who aren't 'in the know' would expect to find it. Because it looks kind of sketchy that the search function of the main documentation section of *the* primary web site for a programming language doesn't work right, and hasn't for some time even though its a 'well-known' issue because it isn't considered a sexy enough problem to be addressed. In my mind, that doesn't say very many *good* things about that language... And before you say, 'Go for it, fix it yourself'... I'm one of those new-ish folks myself, and you probably don't want me tinkering around anywhere near the guts of any search engine ;) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] dict.get() vs. dict.get
What is the difference between dict.get() and dict.get as shown in the code below: counts = dict() for line in input_file: words = line.split() if len(words) == 0: continue else: if words[0] != 'From:': continue else: counts[words[1]] = counts.get(words[1], 0) + 1 max_key = max(counts, key=counts.get) max_value = counts[max_key] print max_key, max_value I know the former (counts.get()) is supposed to return a value for a key if it exists, or else return the default value (in this case '0'). That part of the code is checking to see if the value contained in words[1] exists as a key in the dictionary counts or not; either way increment the associated value by +1. The latter (counts.get) reflects some code I found online [1]: print max(d.keys(), key=lambda x: d[x]) or even shorter (from comment): print max(d, key=d.get) that is to replace manually looping through the dict to find the max value like this: max_value = None max_key = None for key, value in counts.items(): if max_value is None or max_value < value: max_value = value max_key = key print max_key, max_value So... the similarity between dict.get() and dict.get as used here is kinda confusing me. When I do a search for 'dict.get' in the python docs or on google all I normally find is stuff referring to 'dict.get()'. Any pointers would be much appreciated. [1] http://stackoverflow.com/questions/12402015/print-the-key-of-the-max-value-in-a-dictionary-the-pythonic-way -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Python functions are first-class citizens
On 07/31/2014 08:22 PM, Ben Finney wrote:
memilanuk writes:
>> So... the similarity between dict.get() and dict.get as used here is
>> kinda confusing me.
>
> I hope that helps. They are the same function; but the former is
> *calling* the function object, and optionally using the return value;
> the latter is referring to the function object *as* a value.
Conceptually, that makes sense. Practically... having a little trouble
getting my head around it - see below.
max_key = max(counts, key=counts.get)
This specifies ‘counts.get’, without calling it. The expression
‘counts.get’ evaluates to that function object.
That value is then used as the value for the ‘key’ parameter when
calling ‘max’ here.
Been reading a bit more in the mean time, trying to grok that 'key'
parameter for max()... and of course the python docs for max(iterable,
key=) refer to the docs for list.sort() ;)
Kind of diverging off the original question a bit... but since it did
include the max() code in it... I'm having a bit of difficulty with the
whole 'key=' parameter when combined with counts.get here.
So counts is the iterable, and counts.get is the key used to iterate
through it?
I guess I'm not getting how the whole key, function object bit works
here in actual practice.
if we have
counts = {'a':1, 'b':22, 'c':100}
then counts.get('b') should return 22. I got that much.
And counts.get is just an uncalled version of that:
foo = counts.get
foo('b')
should return 22 as well. Think I got that as well.
Where things are going pear-shaped is how counts.get can function as a
'key' when we don't actually supply () (or anything inside them) to
specify what k,v pair we want, and how that relates back to the iterable
for max(), counts?
Monte
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Re: [Tutor] Python functions are first-class citizens
On 07/31/2014 11:46 PM, Ben Finney wrote:
The ‘max’ function can be told how to determine the ordering of items,
by specifying a key parameter. The parameter is specified by giving a
value; that value is a function.
Hmmm... might just have had a break-thru here: so max() iterates thru
counts, which because its the only non-keyword argument provided has to
be an iterable (if I'm reading this correctly:
https://docs.python.org/3/library/functions.html?highlight=max#max). It
takes each dict key ('a', 'b', 'c'), feeds them in turn to counts.get()
like so: counts.get('a'), counts.get('b'), counts.get('c'), which should
return the corresponding dict values (1, 22, 100), and then max()
returns the highest value seen.
Is that about right?
Monte
--
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Reach me @ memilanuk (at) gmail dot com
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Re: [Tutor] Python functions are first-class citizens
On 08/01/2014 01:33 AM, Ben Finney wrote: Ah! Now I get a better idea why you're confused. There are two distinct uses of “key” going on. Ahhh... no. Yes, I realize there were two different uses of 'key' and no, I didn't think they were necessarily the same. * There is no guarantee all the items will be seen. ‘max’ could very well decide it's got the largest item and return it at any point. It's an implementation detail how it does that. What?!? Are you serious? Under what kind of conditions? Broadly, you should consider the ‘max’ function a black box. Yeah, I'm starting to see that... -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Text Editor/IDE for Python
On 09/01/2014 07:36 PM, Juan Christian wrote: Forget guys, we have the true winner, Anaconda (https://sublime.wbond.net/packages/Anaconda) Anaconda turns your Sublime Text 3 in a full featured Python development IDE including autocompletion, code linting, IDE features, autopep8 formating, McCabe complexity checker and Vagrant for Sublime Text 3 using Jedi, PyFlakes, pep8, PyLint, pep257 and McCabe that will never freeze your Sublime Text 3. Weird that they would pick that name given the potential for confusion with this: https://store.continuum.io/cshop/anaconda/ ...unless there is some relation there that I'm missing? I'll admit, I haven't downloaded/installed the Anaconda version of python myself as of yet. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Text Editor/IDE for Python
On 09/03/2014 12:49 AM, Alan Gauld wrote: I can see how it happened, after all anaconda is a snake too so its an "obvious" name for a Python related project... True... but about 15 seconds of due diligence searching google beforehand for 'python anaconda' is all they had to do to avoid the name conflict. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Some shameless self promotion
On 11/02/2014 05:22 PM, Alan Gauld wrote: For anyone who might be interested http://www.amazon.com/Python-Projects-Laura-Cassell/dp/111890866X A book aimed at those who have just finished their first python tutorial and are wondering what to do next... Do you know if there are any plans for an electronic version i.e. pdf or kindle? -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Some shameless self promotion
On 11/03/2014 11:41 PM, Alan Gauld wrote: On 04/11/14 00:55, memilanuk wrote: On 11/02/2014 05:22 PM, Alan Gauld wrote: For anyone who might be interested http://www.amazon.com/Python-Projects-Laura-Cassell/dp/111890866X A book aimed at those who have just finished their first python tutorial and are wondering what to do next... Do you know if there are any plans for an electronic version i.e. pdf or kindle? I assume so but I'm only the author and that's a decision for the publishers! :-) Well, maybe as one of the authors you can poke 'em a bit. So far the only version listed on Amazon or Wrox's site is paperback. -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looking for a Python feature for computer teaching
I believe that Spyder (lightweight IDE often included in scientific python builds like Anaconda, WinPython, python(x,y)) has a variable explorer pane... I'd guess you could 'step' thru the program in debugger mode and watch the variables change in the explorer window. https://code.google.com/p/spyderlib/ https://pythonhosted.org/spyder/variableexplorer.html -- Shiny! Let's be bad guys. Reach me @ memilanuk (at) gmail dot com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
