Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Use a double-negative:</p> <pre><code>/[^\S\n]/ </code></pre> <p>To avoid platform differences <a href="http://perldoc.perl.org/perlport.html#Newlines" rel="noreferrer">warned about in perlport</a> regarding mappings of <code>\r</code> and <code>\n</code>:</p> <pre><code>/[^\S\x0a\x0d]/ </code></pre> <p>That is, not-not-whitespace or not-newline and similar for the pattern that excludes CR and NL.</p> <p>Distributing the outer not (<em>i.e.</em>, the complementing <code>^</code> in the character class) with <a href="http://en.wikipedia.org/wiki/De_Morgan&#39;s_laws" rel="noreferrer">De Morgan's law</a>, this is equivalent to “whitespace and not carriage return and not newline,” but don't take my word for it:</p> <pre><code>#! /usr/bin/env perl use strict; use warnings; use 5.005; # for qr// my $ws_not_nl = qr/[^\S\x0a\x0d]/; for (' ', '\f', '\t', '\r', '\n') { my $qq = qq["$_"]; printf "%-4s =&gt; %s\n", $qq, (eval $qq) =~ $ws_not_nl ? "match" : "no match"; } </code></pre> <p>Output:</p> <pre>" " => match "\f" => match "\t" => match "\r" => no match "\n" => no match</pre> <p>Note the exclusion of vertical tab, but this is <a href="http://search.cpan.org/dist/perl-5.18.0/pod/perldelta.pod#Vertical_tabs_are_now_whitespace" rel="noreferrer">addressed in v5.18</a>.</p> <p>This trick is also handy for matching alphabetic characters. Remember that <code>\w</code> matches “word characters,” alphabetic characters but <em>also</em> digits and underscore. We ugly-Americans sometimes want to write it as, say,</p> <pre><code>if (/^[A-Za-z]+$/) { ... } </code></pre> <p>but a double-negative character-class can respect the locale:</p> <pre><code>if (/^[^\W\d_]+$/) { ... } </code></pre> <p>That is a bit opaque, so a POSIX character-class may be better at expressing the intent</p> <pre><code>if (/^[[:alpha:]]+$/) { ... } </code></pre> <p>or as <a href="https://stackoverflow.com/users/415428/szbalint">szbalint</a> suggested</p> <pre><code>if (/^\p{Letter}+$/) { ... } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POMatch whitespace but not newlines
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USGreg Bacon
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COJust a short note, for Unicode aware matching `/\p{Letter}/` can also be used. It includes letters, but not numbers.
      singulars
      1. PO
      1. USszbalint
    2. COClever, but the behavior is very surprising, and I don't see how it's less awkward.
      singulars
      1. PO
      1. USQwertie
    3. CO@Qwertie: what's surprising? Less awkward than what?
      singulars
      1. PO
      1. USysth
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload