I want to know why we always use Sorting algorithm like (Insertion Sort or Merge Sort,...) just for lists and arrays? And why we do not use these algorithms for stack or queue?
This question is for learning purposes. Suppose I am writing a simple SQL admin console using CGI and Python. At http://something.com/admin, this admin console should allow me to modify a SQL database (i.e., create and modify tables, and create and modify records) using an ordinary form.
In the least secure case, anybody can access http://something.com/admin and modify the database.
You can password protect http://something.com/admin. But once you start using the admin console, information is still transmitted in plain text.
So then you use HTTPS to secure the transmitted data.
Questions:
To describe to a learner, how would you incrementally add security to the least secure environment in order to make it most secure? How would you modify/augment my three (possibly erroneous) steps above?
What basic tools in Python make your steps possible?
Optional: Now that I understand the process, how do sophisticated libraries and frameworks inherently achieve this level of security?
Hi all,
I'm using Jquery's toggle event to do some stuff when a user clicks a checkbox, like this:
$('input#myId').toggle(
function(){
//do stuff
},
function(){
//do other stuff
}
);
The problem is that the checkbox isn't being ticked when I click on the checkbox. (All the stuff I've put into the toggle event is working properly.)
I've tried the following:
$('input#myId').attr('checked', 'checked');
and
$(this).attr('checked', 'checked');
and even simply
return true;
But nothing is working. Can anyone tell me where I'm going wrong?
Edit - thanks to all who replied. Dreas' answer very nearly worked for me, except for the part that checked the attribute. This works perfectly (although it's a bit hacky)
$('input#myInput').change(function ()
{
if(!$(this).hasClass("checked"))
{
//do stuff if the checkbox isn't checked
$(this).addClass("checked");
return;
}
//do stuff if the checkbox isn't checked
$(this).removeClass('checked');
});
Thanks again to all who replied.
//output is "01234 00000" but the output should be or what I want it to be is
// "01234 01234" because of the assignment overloaded operator
#include <iostream>
using namespace std;
class IntArray
{
public:
IntArray() : size(10), used(0) { a= new int[10]; }
IntArray(int s) : size(s), used(0) { a= new int[s]; }
int& operator[]( int index );
IntArray& operator =( const IntArray& rightside );
~IntArray() { delete [] a; }
private:
int *a;
int size;
int used;//for array position
};
int main()
{
IntArray copy;
if( 2>1)
{
IntArray arr(5);
for( int k=0; k<5; k++)
arr[k]=k;
copy = arr;
for( int j=0; j<5; j++)
cout<<arr[j];
}
cout<<" ";
for( int j=0; j<5; j++)
cout<<copy[j];
return 0;
}
int& IntArray::operator[]( int index )
{
if( index >= size )
cout<<"ilegal index in IntArray"<<endl;
return a[index];
}
IntArray& IntArray::operator =( const IntArray& rightside )
{
if( size != rightside.size )//also checks if on both side same object
{
delete [] a;
a= new int[rightside.size];
}
size=rightside.size;
used=rightside.used;
for( int i = 0; i < used; i++ )
a[i]=rightside.a[i];
return *this;
}
Hi stackoverflow,
I apologize in advance for the possible stupidity of this question. However, the following has been the source of some confusion for me and I know the people here will be able to handily clear up the confusion for me. Basically, I would like to finally understand the relationship between any and all of the following terms. Some of the terms I do actually understand pretty well, but some of them are similar in my mind and I would like to once and for all to see their relationships/distinctions laid out all at once. They are:
compiler
interpreter
bytecode
machine code
assembler
assembly language
binary
object code
executable
Ideally, an answer would use examples from Java and C++ and other well-known programming languages that a young-ish student like me would be familiar with. Also, if you want to throw in any other useful terms that would be fine too :)
I really want to learn how to program. A friend suggested I buy vs 2005 or a newer version if I'm serious about it. Is there a cheaper route? I would like to start with c#.
Hello everyone,
I have some experience in Scheme and C++ (read: a semester of each) I know the very basics of Python (used it for physics simulations with the Visual Python module).
Can you recommend me some fun and small (i.e. don't take much time) projects on either Python or C++? I have no real preferences, just that it is fun :P
Thanks for your time!
PS: I've tried projecteuler and python challenge. Euler is good, but more about math than coding, and py challenge just didn't work for me.
I'm trying to write a simple decorator to check the authentication of a user, and to redirect to the login page if s/he is not authenticated:
def authenticate(f):
try:
if user['authenticated'] is True:
return f
except:
redirect_to(controller='login', action='index')
class IndexController(BaseController):
@authenticate
def index(self):
return render('/index.mako' )
But this approach doesn't work. When a user is authenticated, everything is fine. But when the user is not authenticated, redirect_to() doesn't work and I am given this error:
HTTPFound: 302 Found Content-Type: text/html; charset=UTF-8 Content-Length: 0 location: /login
Thank for your help!
Frustrated in finding the .jar -balls like google collections or "package org.apache.commons.io;". Is there some utility to get them fast like the style-"apt-get source app"? "get-java-jar-ball-3rd source apache commons"?
Dear all,
I've a list of float numbers and I would like to delete incrementally
a set of elements in a given range of indexes, sth. like:
for j in range(beginIndex, endIndex+1):
print ("remove [%d] => val: %g" % (j, myList[j]))
del myList[j]
However, since I'm iterating over the same list, the indexes (range)
are not valid any more for the new list.
Does anybody has some suggestions on how to delete the elements
properly?
Best wishes
/* in this slice of code I get an output of
bbb 55 66 77 88
aaa
the output I expect and want is
bbb 55 66 77 88
bbb
because I reassign ss from log[0] to log[1]
So my question is why is the output different from what I expect and how do I
change it to what I want?
*/
int w,x,y,z;
stringstream ss (stringstream::in | stringstream::out);
string word;
string log[2];
log[0]="aaa 11 22 33 44";
log[1]="bbb 55 66 77 88";
ss<<log[0];
ss>>word;
int k=0;
ss>>w>>x>>y>>z;
k++;
ss<<log[k];
cout<<log[k]<<endl;
ss>>word;
cout<<word<<endl;
return 0;
I just had a look at Suns Java tutorial, and found something that totally confused me:
Given the following example:
public Bicycle(int startCadence, int startSpeed, int startGear) {
gear = startGear;
cadence = startCadence;
speed = startSpeed;
}
Why is it, that the types of the variables (fields?) gear, cadence and speed do not need to be defined?
I would have written it as follows:
public Bicycle(int startCadence, int startSpeed, int startGear) {
int gear = startGear;
int cadence = startCadence;
int speed = startSpeed;
}
What would be the actual differnce?
This code works fine to find an available room within certain date, but it does not work to show a room that has been booked and canceled
The "hotel" has 4 rooms and 1 of them has been booked an canceled
So even if I make a cancelation, the select method keeps giving me 3 results. Maybe because the second AND is still running. So basically what I need is
check if the room is booked in the selected dates
if it has been booked, check if its canceled
if it has been canceled, or not booked display it. Otherwise not
SELECT RoomNo, NightCost
FROM room, room_types, booking
WHERE typeid = fk1_typeid
and double_bed=1
and single_bed=0
AND canceled = '1' in
(SELECT canceled
from booking, room_booking
where bookingid = fk2_bookingid)
AND RoomNo not in
(SELECT fk1_RoomNo
FROM room_booking
WHERE '2010-04-02' between Check_in
and Check_Out or
'2010-04-03' between Check_in
and Check_Out) ;
I tried to be as clear as possible, i will be around to give more details if needed
My code reads:
import Image
def generateThumbnail(self, width, height):
"""
Generates thumbnails for an image
"""
im = Image.open(self._file)
When I call this function, I get an error:
? AttributeError: type object 'Image' has no attribute 'open'
However in the console:
import Image
im = Image.open('test.jpg')
I have no problem.
Any ideas?
Thanks!
I need to get the minimum and maximum values in a collection of floating point values, after applying an absolute value conversion. In python I would do this
min(map(abs, [-5, -7, 10, 2]))
how can I perform the same operation in java in the most elegant way?
We have a an iPhone app project that we wish to deploy multiple times under different client names. The individual apps will be very similar but will have different resources (icon, images etc) and config settings stored in plists (server names, options etc). What is the preferred means to manage this in Xcode? Obviously we really don't want different XCode projects for each App deployment since it's 90% shared code.
Hi All
I need to read a CSV file in python.
Since for last row I receive a 'NULL byte' error I would like to avoid using for keyword but the while.
Do you know how to do that?
reader = csv.reader( file )
for row in reader # I have an error at this line
# do whatever with row
I want to substitute the for-loop with a while-loop so that I can check if the row is NULL or not.
What is the function for reading a single row in the CSV module?
Thanks
Thanks
p.S. below the traceback
Traceback (most recent call last):
File "FetchNeuro_TodayTrades.py", line 189, in
for row in reader:
_csv.Error: line contains NULL byte
I'm working through a book on Ruby, and the author used a slightly different form for writing a class initialization definition than he has in previous sections of the book. It looks like this:
class Ticket
attr_accessor :venue, :date
def initialize(venue, date)
self.venue = venue
self.date = date
end
end
In previous sections of the book, it would've been defined like this:
class Ticket
attr_accessor :venue, :date
def initialize(venue, date)
@venue = venue
@date = date
end
end
Is there any functional difference between using the setter method, as in the first example vs. using the instance variable in the second? They both seem to work. Even mixing them up seems to work:
class Ticket
attr_accessor :venue, :date
def initialize(venue, date)
@venue = venue
self.date = date
end
end
I'm new to Python, and I know I must be missing something pretty simple, but why doesn't this very, very simple code work?
class myClass:
pass
testObject = myClass
print testObject.__class__
I get the following error:
AttributeError: class myClass has no attribute '__class__'
Doesn't every object in Python have a __class__ attribute?
What I'm trying to do is make a basic flashcard app on rails. At this point, all I'm looking for is the functionality to iterate through a list of flashcards, quiz the user and let the user know if they were right or not. In ruby, it didn't take me long to write:
class Card
attr_accessor :answer, :question
def initialize(answer = "", question="")
@answer = answer
@question = question
end
def quiz
puts "What does #@question mean?"
answer = gets.chomp
if answer == @answer
puts "Right"
return true
else
puts "Wrong"
return answer
end
end
end
class Cardlist
attr_accessor :Cards
def initialize(Cards = [])
@Cards = Cards
end
def quiz
Cards.each do |w|
w.quiz
end
end
end
The problem I'm having with rails is figuring out where to put the logic to loop through all the cards in the list. I've made models specifying that Card belongs_to cardlist and that Cardlist has_many cards. I know application logic should go in the controller, but if I were to make a "quiz" action for my Cardlist controller, how would I make it iterate through all the cards? After each "quiz" page generated, I'd need to get an answer back from the user, respond (maybe flash) whether it was right or not and then continue onto the next question. Would any of that logic have to go into the view in order to make sure it's sending back the user inputted answers to the controller?
How can I look up a hostname given an IP address? Furthermore, how can I specify a timeout in case no such reverse DNS entry exists? Trying to keep things as fast as possible. Or is there a better way? Thank you!
I've noticed many questions on here from new programmers that can be solved using libraries. When a library is suggested, often times they respond "I don't want to use X library" Is it the learning curve? or ? Just curious!
In order to place my models in sub-folders I tried to use the app_label Meta field as described here.
My directory structure looks like this:
project
apps
foo
models
_init_.py
bar_model.py
In bar_model.py I define my Model like this:
from django.db import models
class SomeModel(models.Model):
field = models.TextField()
class Meta:
app_label = "foo"
I can successfully import the model like so:
from apps.foo.models.bar_model import SomeModel
However, running:
./manage.py syncdb
does not create the table for the model. In verbose mode I do see, however, that the app "foo" is properly recognized (it's in INSTALLED_APPS in settings.py). Moving the model to models.py under foo does work.
Is there some specific convention not documented with app_label or with the whole mechanism that prevents this model structure from being recognized by syncdb?