Why do I have to add a blank __init__.py file to import from subdirectories I can import from subdirectories with a blank __init__.py file. That works fine. I think that init file in python works like an index file. But I really don't understand why the __init__.py file is blank to import. How do __init__.py file and importing really work?  What have to be __init__.py files content?
What is __init__.py for? What is __init__.py for in a Python source directory?
I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ } &lt;table id="page"&gt;     &lt;tr&gt;         &lt;td id="tdheader"&gt;             &lt;div id="header"&gt;...&lt;/div&gt;         &lt;/td&gt;     &lt;/tr&gt;     &lt;tr&gt;         &lt;td id="tdcontent"&gt;             &lt;div id="content"&gt;...&lt;/div&gt;         &lt;/td&gt;     &lt;/tr&gt; &lt;/table&gt;     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works. When you have a link from lets say twitter that is t.co/foo that links back to your website how does that effect SEO and how do the major search engines handle Shortened URLs? I am using Ubuntu 17.10 on my desktop PC, I've been monitoring network traffic with Etherape. I noticed HTTP requests from my PC(casa hostname) to googleusercontent.com (104.198.143.177). So I used lsof and ss to 'identify' process behind these requests.    Using lsof -i:   NetworkMa  778            root   20u  IPv4 546772      0t0  TCP casa:53671-&gt;177.143.198.104.bc.googleusercontent.com:http (SYN_SENT) NetworkMa  778            root   20u  IPv4 546772      0t0  TCP casa:53671-&gt;177.143.198.104.bc.googleusercontent.com:http (ESTABLISHED)   Using ss -rep dst 104.198.143.177:    tcp    SYN-SENT   0      1      casa%enp4s0:53671    177.143.198.104.bc.googleusercontent.com:http  users:(("NetworkManager",pid=778,fd=20)) timer:(on,964ms,0) ino:546772 sk:6df &lt;-&gt; tcp    ESTAB      0      87     casa%enp4s0:53671    177.143.198.104.bc.googleusercontent.com:http  users:(("NetworkManager",pid=778,fd=20)) timer:(on,300ms,0) ino:546772 sk:6df &lt;-&gt;   It seems NetworkManager (pid 778) is sending requests to googleusercontent, and it happens every 5 minutes exactly.   I have to say, no applications were launched at the moment, no background process, no network activities,no online account and it was a 'Ubuntu fresh install'. So why NM would sent requests to googleusercontent? Where can I access OS X keyboard shortcuts, say for Dropbox sync? Which story is true at end of the movie "Life of Pi"? At the end of the movie  Pi tells us two stories. One with the tiger (unrealistic) and one without the tiger (realistic).  I believe that he was metaphorically referring himself as the tiger who enters the forest (world) after being rescued.  Is my thinking correct? can you explain me the ending?  At the end did Irfan Khan (older Pi/narrator) say that "even God chose the first story"? Does it mean that the first story was indeed real? How to add a realistic flare How do I turn the little emission sphere into a realistic flaring sun. (This piece is animated with all the planets rotating and revolving) The  that is defined as $Y_{t} = Y_{t-1} + e_t$, where $e_t$ is white noise. Denotes that the current position is the sum of the previous position + an unpredicted term. You can prove that the mean function $\mu_t = 0 $, since $$E(Y_{t}) = E(e_1+ e_2+ ... +e_t) = E(e_1) + E(e_2) +... +E(e_t) = 0 + 0 + \cdots + 0$$ But why is it that the variance increases linearly with time? Does this have something to do with it's not “pure” random, since the new position is very correlated with the previous one? EDIT: Now I have a much better understanding by visualizing a big sample of random walks, and here we can easily observe that the overall variance does increase over time,  and the mean is as expected around zero. Maybe this was trivial after all, since in the very early stages of the time series (compare time = 10 with time = 100) the random walkers have not had yet the time to explore as much. Creating a single index from several principal components or factors retained from PCA/FA I am using Principal Component Analysis (PCA) to create an index required for my research. My question is how I should create a single index by using the retained principal components calculated through PCA.  For instance, I decided to retain 3 principal components after using PCA and I computed scores for these 3 principal components. What is the appropriate ways to create, for each respondent, a single index out of these 3 scores?   Is it relevant to add the 3 computed scores to have a composite value? Or to average the 3 scores to have such a value?  Or should I just keep the first principal component (the strongest) only and use its score as the index?   Alternatively, one could use Factor Analysis (FA) but the same question remains: how to create a single index based on several factor scores? Suppose $f,g$: $\Bbb R$ → $\Bbb R$ are continuous functions such that $f(r) = g(r)$ for all $r$ in $\Bbb Q$. That is to say, $f$ and $g$ are equal on the rational numbers.   Prove that  $f(x) = g(x)$  for all $x$ in $\Bbb R$ How to use grep output as a path for cd? I want to know if there is another way to solve the equation:  $$(x+1)^y-x^z=1$$  for positive integers $x,y,z$ greater than $1$ without using the Catalan identity. Does exist? By now I only know that $x\mid y$. Can I leave South Africa before my 90 days expire, and return after a few days to stay for another 90 days? How many times can an Australian leave and re-enter South Africa (90 days at a time without a visa) in a year, and do they need to be out of the country for a certain period of time before they re-enter?  I want to be in South Africa for as long as I can, however as an Australian without a visa I can only stay for 90 days at a time. What I would like to do is simply leave South Africa and go to another country in Africa for a few days, before returning with a new 90 day allowance.    Is this possible, or must I wait a certain period before re-entering South Africa/is there a limit to the amount of times I can do this in one year? How to use THAT and WHO I've found strange behavior when closing this  - I definitely see that there are 3 closing votes and 2 of them are at "Off-topic" section:   -but there are no explanations on section itself:   -while, normally, it's expected that it will appear. In custom comments section there are also no closing-votes displayed.   Perhaps it's just my browser (which is FF 26 x64 under Win) - so marking this as a "possible bug". Thank you for your attention. Is it possible to install multiple instances of the same delphi service application? Custom unique constraint, only enforced if one column has a specific value So to help prevent brute force attacks against my phpmyadmin install I've configured nginx to require HTTP Basic Auth (extra username and password) and then the requests need to come from a whitelisted IP Address. However the IP Address whitelist works fine if I run  however without adding the extra .php block I could load  without my IP being whitelisted. This issue doesn't affect the HTTP Basic Auth. Is there a reason this happens? Anyway to get around having to add extra .php blocks? A copy of the config area for phpmyadmin is below.  # Setup and secure phpMyAdmin location /phpmyadmin/ {   allow 1.2.3.4;   deny all;   auth_basic "phpMyAdmin - HTTP Basic Login";       auth_basic_user_file /etc/nginx/pma_pass;     location ~ \.php$ {     include snippets/fastcgi-php.conf;             fastcgi_pass unix:/run/php/php7.0-fpm.sock;     allow 1.2.3.4;     deny all;     } } How can I achieve having logical page numbers shown in acrobat reader? I'm a trainee teacher and I need to pass a skills test in maths, but I'm having trouble in this particular area of algebra in finding the nth term of any sequence. I've been given a series of questions to answer one of them is:  Find the nth term of the sequence 3, 8, 15, 24.  I not only need to know the answer but more importantly the technique. This is GCSE level. Clickable Table Footnote I'm trying to have some clickable footnotes within tables. I tried using \footnote{}, it does create a link but there's no footnote text associated with it. \footnotemark[number] along with \footnotetext[]{} does create a fotenote but then there's no hyperlink. (I would like to make it clear that I'm trying to have footnotes at the bottom of the page and not footnotes within the table.)  Here's a small code snippet:  \documentclass{report}  \usepackage{hyperref} \begin{document}  \begin{table}[h!]     \centering     \begin{tabular}{|r|r|r|}         \hline         A\footnote{Test!} &amp; B\footnotemark[4] &amp; C\footnotemark[5]\\         \hline         123 &amp; Tim &amp; Jane\\         \hline         456 &amp; Tom &amp; Jung\\         \hline     \end{tabular}     \caption{A table} \end{table}  This is a clickable footnote\footnote{You clicked me!}.  \footnotetext[4]{This is B} \footnotetext[5]{This is C}  \end{document}