Major changes to Combinatorics and Datetime

README.md

@@ -544,68 +544,65 @@ from random import random, randint, choice        # Also: shuffle, gauss, triang
 
 Combinatorics
 -------------
-* **Every function returns an iterator.**
-* **If you want to print the iterator, you need to pass it to the list() function first!**
-
 ```python
 import itertools as it
 ```
 
 ```python
->>> it.product([0, 1], repeat=3)
+>>> list(it.product([0, 1], repeat=3))
 [(0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1),
  (1, 0, 0), (1, 0, 1), (1, 1, 0), (1, 1, 1)]
 ```
 
 ```python
->>> it.product('abc', 'abc')                     #   a  b  c
-[('a', 'a'), ('a', 'b'), ('a', 'c'),             # a x  x  x
- ('b', 'a'), ('b', 'b'), ('b', 'c'),             # b x  x  x
- ('c', 'a'), ('c', 'b'), ('c', 'c')]             # c x  x  x
+>>> list(it.product('abc', 'abc'))                    #   a  b  c
+[('a', 'a'), ('a', 'b'), ('a', 'c'),                  # a x  x  x
+ ('b', 'a'), ('b', 'b'), ('b', 'c'),                  # b x  x  x
+ ('c', 'a'), ('c', 'b'), ('c', 'c')]                  # c x  x  x
 ```
 
 ```python
->>> it.combinations('abc', 2)                    #   a  b  c
-[('a', 'b'), ('a', 'c'),                         # a .  x  x
- ('b', 'c')]                                     # b .  .  x
+>>> list(it.combinations('abc', 2))                   #   a  b  c
+[('a', 'b'), ('a', 'c'),                              # a .  x  x
+ ('b', 'c')]                                          # b .  .  x
 ```
 
 ```python
->>> it.combinations_with_replacement('abc', 2)   #   a  b  c
-[('a', 'a'), ('a', 'b'), ('a', 'c'),             # a x  x  x
- ('b', 'b'), ('b', 'c'),                         # b .  x  x
- ('c', 'c')]                                     # c .  .  x
+>>> list(it.combinations_with_replacement('abc', 2))  #   a  b  c
+[('a', 'a'), ('a', 'b'), ('a', 'c'),                  # a x  x  x
+ ('b', 'b'), ('b', 'c'),                              # b .  x  x
+ ('c', 'c')]                                          # c .  .  x
 ```
 
 ```python
->>> it.permutations('abc', 2)                    #   a  b  c
-[('a', 'b'), ('a', 'c'),                         # a .  x  x
- ('b', 'a'), ('b', 'c'),                         # b x  .  x
- ('c', 'a'), ('c', 'b')]                         # c x  x  .
+>>> list(it.permutations('abc', 2))                   #   a  b  c
+[('a', 'b'), ('a', 'c'),                              # a .  x  x
+ ('b', 'a'), ('b', 'c'),                              # b x  .  x
+ ('c', 'a'), ('c', 'b')]                              # c x  x  .
 ```
 
 
 Datetime
 --------
-* **Module 'datetime' provides 'date' `<D>`, 'time' `<T>`, 'datetime' `<DT>` and 'timedelta' `<TD>` classes. All are immutable and hashable.**
-* **Time and datetime objects can be 'aware' `<a>`, meaning they have defined timezone, or 'naive' `<n>`, meaning they don't.**
-* **If object is naive, it is presumed to be in the system's timezone.**
+**Provides 'date', 'time', 'datetime' and 'timedelta' classes. All are immutable and hashable.**
 
 ```python
-from datetime import date, time, datetime, timedelta
-from dateutil.tz import UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
+# pip3 install python-dateutil
+from datetime import date, time, datetime, timedelta, timezone
+from dateutil.tz import tzlocal, gettz, datetime_exists, resolve_imaginary
 ```
 
-### Constructors
 ```python
 <D>  = date(year, month, day)               # Only accepts valid dates from 1 to 9999 AD.
 <T>  = time(hour=0, minute=0, second=0)     # Also: `microsecond=0, tzinfo=None, fold=0`.
 <DT> = datetime(year, month, day, hour=0)   # Also: `minute=0, second=0, microsecond=0, …`.
 <TD> = timedelta(weeks=0, days=0, hours=0)  # Also: `minutes=0, seconds=0, microseconds=0`.
 ```
-* **Use `'<D/DT>.weekday()'` to get the day of the week as an int, with Monday being 0.**
+* **Aware `<a>` time and datetime objects have defined timezone, while naive `<n>` don't.**
+* **If object is naive, it is presumed to be in the system's timezone.**
 * **`'fold=1'` means the second pass in case of time jumping back for one hour.**
 * **Timedelta normalizes arguments to ±days, seconds (< 86 400) and microseconds (< 1M).**
+* **Use `'<D/DT>.weekday()'` to get the day of the week as an int, with Monday being 0.**
 * **`'<DTa> = resolve_imaginary(<DTa>)'` fixes DTs that fall into the missing hour.**
 
 ### Now
@@ -618,12 +615,14 @@ from dateutil.tz import UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
 
 ### Timezone
 ```python
-<tzinfo> = UTC                              # UTC timezone. London without DST.
+<tzinfo> = timezone.utc                     # London without daylight saving time.
+<tzinfo> = timezone(<timedelta>)            # Timezone with fixed offset from UTC.
 <tzinfo> = tzlocal()                        # Local timezone. Also gettz().
 <tzinfo> = gettz('<Continent>/<City>')      # 'Continent/City_Name' timezone or None.
 <DTa>    = <DT>.astimezone(<tzinfo>)        # Datetime, converted to the passed timezone.
 <Ta/DTa> = <T/DT>.replace(tzinfo=<tzinfo>)  # Unconverted object with a new timezone.
 ```
+* **Standard library's zoneinfo.ZoneInfo() can be used instead of gettz() on Python 3.9 and later. It requires 'tzdata' package on Windows.**
 
 ### Encode
 ```python
@@ -651,7 +650,8 @@ from dateutil.tz import UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
 >>> dt.strftime("%A, %dth of %B '%y, %I:%M%p %Z")
 "Thursday, 14th of May '15, 11:39PM UTC+02:00"
 ```
-* **Format code `'%z'` accepts `'±HH[:]MM'` and returns `'±HHMM'` (or `''` if datetime is naive).**
+* **`'%z'` accepts `'±HH[:]MM'` and returns `'±HHMM'` or empty string if datetime is naive.**
+* **`'%Z'` accepts `'UTC/GMT'` and local timezone's code and returns timezone's name, `'UTC[±HH:MM]'` if timezone is nameless, or an empty string if datetime is naive.**
 * **For abbreviated weekday and month use `'%a'` and `'%b'`.**
 
 ### Arithmetics
@@ -659,7 +659,7 @@ from dateutil.tz import UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
 <D/DT>   = <D/DT>  ± <TD>                   # Returned datetime can fall into missing hour.
 <TD>     = <D/DTn> - <D/DTn>                # Returns the difference. Ignores time jumps.
 <TD>     = <DTa>   - <DTa>                  # Ignores time jumps if they share tzinfo object.
-<TD>     = <TD>    * <real>                 # Also: <TD> = abs(<TD>) and <TD> = <TD> ±% <TD>.
+<TD>     = <TD>    * <int/float>            # Also: <TD> = abs(<TD>) and <TD> = <TD> ±% <TD>.
 <float>  = <TD>    / <TD>                   # How many weeks/years there are in TD. Also //.
 ```
 

index.html

@@ -54,7 +54,7 @@
 
 <body>
   <header>
-    <aside>July 30, 2023</aside>
+    <aside>July 31, 2023</aside>
     <a href="https://gto76.github.io" rel="author">Jure Šorn</a>
   </header>
 
@@ -489,55 +489,49 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
 &lt;int&gt; = ~&lt;int&gt;                                    <span class="hljs-comment"># Not. Also -&lt;int&gt; - 1.</span>
 </code></pre></div>
 
-<div><h2 id="combinatorics"><a href="#combinatorics" name="combinatorics">#</a>Combinatorics</h2><ul>
-<li><strong>Every function returns an iterator.</strong></li>
-<li><strong>If you want to print the iterator, you need to pass it to the list() function first!</strong></li>
-</ul><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> itertools <span class="hljs-keyword">as</span> it
+<div><h2 id="combinatorics"><a href="#combinatorics" name="combinatorics">#</a>Combinatorics</h2><pre><code class="python language-python hljs"><span class="hljs-keyword">import</span> itertools <span class="hljs-keyword">as</span> it
 </code></pre></div>
 
-
-<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.product([<span class="hljs-number">0</span>, <span class="hljs-number">1</span>], repeat=<span class="hljs-number">3</span>)
+<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.product([<span class="hljs-number">0</span>, <span class="hljs-number">1</span>], repeat=<span class="hljs-number">3</span>))
 [(<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">0</span>, <span class="hljs-number">1</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">0</span>, <span class="hljs-number">1</span>, <span class="hljs-number">1</span>),
  (<span class="hljs-number">1</span>, <span class="hljs-number">0</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">0</span>, <span class="hljs-number">1</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">1</span>, <span class="hljs-number">0</span>), (<span class="hljs-number">1</span>, <span class="hljs-number">1</span>, <span class="hljs-number">1</span>)]
 </code></pre>
-<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.product(<span class="hljs-string">'abc'</span>, <span class="hljs-string">'abc'</span>)                     <span class="hljs-comment">#   a  b  c</span>
-[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),             <span class="hljs-comment"># a x  x  x</span>
- (<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),             <span class="hljs-comment"># b x  x  x</span>
- (<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)]             <span class="hljs-comment"># c x  x  x</span>
+<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.product(<span class="hljs-string">'abc'</span>, <span class="hljs-string">'abc'</span>))                    <span class="hljs-comment">#   a  b  c</span>
+[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                  <span class="hljs-comment"># a x  x  x</span>
+ (<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),                  <span class="hljs-comment"># b x  x  x</span>
+ (<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)]                  <span class="hljs-comment"># c x  x  x</span>
 </code></pre>
-<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.combinations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)                    <span class="hljs-comment">#   a  b  c</span>
-[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                         <span class="hljs-comment"># a .  x  x</span>
- (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>)]                                     <span class="hljs-comment"># b .  .  x</span>
+<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.combinations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>))                   <span class="hljs-comment">#   a  b  c</span>
+[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                              <span class="hljs-comment"># a .  x  x</span>
+ (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>)]                                          <span class="hljs-comment"># b .  .  x</span>
 </code></pre>
-<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.combinations_with_replacement(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)   <span class="hljs-comment">#   a  b  c</span>
-[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),             <span class="hljs-comment"># a x  x  x</span>
- (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),                         <span class="hljs-comment"># b .  x  x</span>
- (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)]                                     <span class="hljs-comment"># c .  .  x</span>
+<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.combinations_with_replacement(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>))  <span class="hljs-comment">#   a  b  c</span>
+[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                  <span class="hljs-comment"># a x  x  x</span>
+ (<span class="hljs-string">'b'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),                              <span class="hljs-comment"># b .  x  x</span>
+ (<span class="hljs-string">'c'</span>, <span class="hljs-string">'c'</span>)]                                          <span class="hljs-comment"># c .  .  x</span>
 </code></pre>
-<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>it.permutations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>)                    <span class="hljs-comment">#   a  b  c</span>
-[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                         <span class="hljs-comment"># a .  x  x</span>
- (<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),                         <span class="hljs-comment"># b x  .  x</span>
- (<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>)]                         <span class="hljs-comment"># c x  x  .</span>
+<pre><code class="python language-python hljs"><span class="hljs-meta">&gt;&gt;&gt; </span>list(it.permutations(<span class="hljs-string">'abc'</span>, <span class="hljs-number">2</span>))                   <span class="hljs-comment">#   a  b  c</span>
+[(<span class="hljs-string">'a'</span>, <span class="hljs-string">'b'</span>), (<span class="hljs-string">'a'</span>, <span class="hljs-string">'c'</span>),                              <span class="hljs-comment"># a .  x  x</span>
+ (<span class="hljs-string">'b'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'b'</span>, <span class="hljs-string">'c'</span>),                              <span class="hljs-comment"># b x  .  x</span>
+ (<span class="hljs-string">'c'</span>, <span class="hljs-string">'a'</span>), (<span class="hljs-string">'c'</span>, <span class="hljs-string">'b'</span>)]                              <span class="hljs-comment"># c x  x  .</span>
 </code></pre>
-<div><h2 id="datetime"><a href="#datetime" name="datetime">#</a>Datetime</h2><ul>
-<li><strong>Module 'datetime' provides 'date' <code class="apache hljs"><span class="hljs-section">&lt;D&gt;</span></code>, 'time' <code class="apache hljs"><span class="hljs-section">&lt;T&gt;</span></code>, 'datetime' <code class="apache hljs"><span class="hljs-section">&lt;DT&gt;</span></code> and 'timedelta' <code class="apache hljs"><span class="hljs-section">&lt;TD&gt;</span></code> classes. All are immutable and hashable.</strong></li>
-<li><strong>Time and datetime objects can be 'aware' <code class="apache hljs"><span class="hljs-section">&lt;a&gt;</span></code>, meaning they have defined timezone, or 'naive' <code class="apache hljs"><span class="hljs-section">&lt;n&gt;</span></code>, meaning they don't.</strong></li>
-<li><strong>If object is naive, it is presumed to be in the system's timezone.</strong></li>
-</ul><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> datetime <span class="hljs-keyword">import</span> date, time, datetime, timedelta
-<span class="hljs-keyword">from</span> dateutil.tz <span class="hljs-keyword">import</span> UTC, tzlocal, gettz, datetime_exists, resolve_imaginary
+<div><h2 id="datetime"><a href="#datetime" name="datetime">#</a>Datetime</h2><p><strong>Provides 'date', 'time', 'datetime' and 'timedelta' classes. All are immutable and hashable.</strong></p><pre><code class="python language-python hljs"><span class="hljs-comment"># pip3 install python-dateutil</span>
+<span class="hljs-keyword">from</span> datetime <span class="hljs-keyword">import</span> date, time, datetime, timedelta, timezone
+<span class="hljs-keyword">from</span> dateutil.tz <span class="hljs-keyword">import</span> tzlocal, gettz, datetime_exists, resolve_imaginary
 </code></pre></div>
 
 
-<div><h3 id="constructors">Constructors</h3><pre><code class="python language-python apache hljs">&lt;D&gt;  = date(year, month, day)               <span class="hljs-comment"># Only accepts valid dates from 1 to 9999 AD.</span>
+<pre><code class="python language-python apache hljs">&lt;D&gt;  = date(year, month, day)               <span class="hljs-comment"># Only accepts valid dates from 1 to 9999 AD.</span>
 &lt;T&gt;  = time(hour=<span class="hljs-number">0</span>, minute=<span class="hljs-number">0</span>, second=<span class="hljs-number">0</span>)     <span class="hljs-comment"># Also: `microsecond=0, tzinfo=None, fold=0`.</span>
 &lt;DT&gt; = datetime(year, month, day, hour=<span class="hljs-number">0</span>)   <span class="hljs-comment"># Also: `minute=0, second=0, microsecond=0, …`.</span>
 &lt;TD&gt; = timedelta(weeks=<span class="hljs-number">0</span>, days=<span class="hljs-number">0</span>, hours=<span class="hljs-number">0</span>)  <span class="hljs-comment"># Also: `minutes=0, seconds=0, microseconds=0`.</span>
-</code></pre></div>
-
+</code></pre>
 <ul>
-<li><strong>Use <code class="python hljs"><span class="hljs-string">'&lt;D/DT&gt;.weekday()'</span></code> to get the day of the week as an int, with Monday being 0.</strong></li>
+<li><strong>Aware <code class="apache hljs"><span class="hljs-section">&lt;a&gt;</span></code> time and datetime objects have defined timezone, while naive <code class="apache hljs"><span class="hljs-section">&lt;n&gt;</span></code> don't.</strong></li>
+<li><strong>If object is naive, it is presumed to be in the system's timezone.</strong></li>
 <li><strong><code class="python hljs"><span class="hljs-string">'fold=1'</span></code> means the second pass in case of time jumping back for one hour.</strong></li>
 <li><strong>Timedelta normalizes arguments to ±days, seconds (&lt; 86 400) and microseconds (&lt; 1M).</strong></li>
+<li><strong>Use <code class="python hljs"><span class="hljs-string">'&lt;D/DT&gt;.weekday()'</span></code> to get the day of the week as an int, with Monday being 0.</strong></li>
 <li><strong><code class="python hljs"><span class="hljs-string">'&lt;DTa&gt; = resolve_imaginary(&lt;DTa&gt;)'</span></code> fixes DTs that fall into the missing hour.</strong></li>
 </ul>
 <div><h3 id="now">Now</h3><pre><code class="python language-python hljs">&lt;D/DTn&gt;  = D/DT.today()                     <span class="hljs-comment"># Current local date or naive datetime.</span>
@@ -548,13 +542,17 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
 <ul>
 <li><strong>To extract time use <code class="python hljs"><span class="hljs-string">'&lt;DTn&gt;.time()'</span></code>, <code class="python hljs"><span class="hljs-string">'&lt;DTa&gt;.time()'</span></code> or <code class="python hljs"><span class="hljs-string">'&lt;DTa&gt;.timetz()'</span></code>.</strong></li>
 </ul>
-<div><h3 id="timezone">Timezone</h3><pre><code class="python language-python apache hljs">&lt;tzinfo&gt; = UTC                              <span class="hljs-comment"># UTC timezone. London without DST.</span>
+<div><h3 id="timezone">Timezone</h3><pre><code class="python language-python apache hljs">&lt;tzinfo&gt; = timezone.utc                     <span class="hljs-comment"># London without daylight saving time.</span>
+&lt;tzinfo&gt; = timezone(&lt;timedelta&gt;)            <span class="hljs-comment"># Timezone with fixed offset from UTC.</span>
 &lt;tzinfo&gt; = tzlocal()                        <span class="hljs-comment"># Local timezone. Also gettz().</span>
 &lt;tzinfo&gt; = gettz(<span class="hljs-string">'&lt;Continent&gt;/&lt;City&gt;'</span>)      <span class="hljs-comment"># 'Continent/City_Name' timezone or None.</span>
 &lt;DTa&gt;    = &lt;DT&gt;.astimezone(&lt;tzinfo&gt;)        <span class="hljs-comment"># Datetime, converted to the passed timezone.</span>
 &lt;Ta/DTa&gt; = &lt;T/DT&gt;.replace(tzinfo=&lt;tzinfo&gt;)  <span class="hljs-comment"># Unconverted object with a new timezone.</span>
 </code></pre></div>
 
+<ul>
+<li><strong>Standard library's zoneinfo.ZoneInfo() can be used instead of gettz() on Python 3.9 and later. It requires 'tzdata' package on Windows.</strong></li>
+</ul>
 <div><h3 id="encode">Encode</h3><pre><code class="python language-python apache hljs">&lt;D/T/DT&gt; = D/T/DT.fromisoformat(<span class="hljs-string">'&lt;iso&gt;'</span>)    <span class="hljs-comment"># Object from ISO string. Raises ValueError.</span>
 &lt;DT&gt;     = DT.strptime(&lt;str&gt;, <span class="hljs-string">'&lt;format&gt;'</span>)   <span class="hljs-comment"># Datetime from str, according to format.</span>
 &lt;D/DTn&gt;  = D/DT.fromordinal(&lt;int&gt;)          <span class="hljs-comment"># D/DTn from days since the Gregorian NYE 1.</span>
@@ -579,13 +577,14 @@ Point(x=<span class="hljs-number">1</span>, y=<span class="hljs-number">2</span>
 </code></pre></div>
 
 <ul>
-<li><strong>Format code <code class="python hljs"><span class="hljs-string">'%z'</span></code> accepts <code class="python hljs"><span class="hljs-string">'±HH[:]MM'</span></code> and returns <code class="python hljs"><span class="hljs-string">'±HHMM'</span></code> (or <code class="python hljs"><span class="hljs-string">''</span></code> if datetime is naive).</strong></li>
+<li><strong><code class="python hljs"><span class="hljs-string">'%z'</span></code> accepts <code class="python hljs"><span class="hljs-string">'±HH[:]MM'</span></code> and returns <code class="python hljs"><span class="hljs-string">'±HHMM'</span></code> or empty string if datetime is naive.</strong></li>
+<li><strong><code class="python hljs"><span class="hljs-string">'%Z'</span></code> accepts <code class="python hljs"><span class="hljs-string">'UTC/GMT'</span></code> and local timezone's code and returns timezone's name, <code class="python hljs"><span class="hljs-string">'UTC[±HH:MM]'</span></code> if timezone is nameless, or an empty string if datetime is naive.</strong></li>
 <li><strong>For abbreviated weekday and month use <code class="python hljs"><span class="hljs-string">'%a'</span></code> and <code class="python hljs"><span class="hljs-string">'%b'</span></code>.</strong></li>
 </ul>
 <div><h3 id="arithmetics">Arithmetics</h3><pre><code class="python language-python apache hljs">&lt;D/DT&gt;   = &lt;D/DT&gt;  ± &lt;TD&gt;                   <span class="hljs-comment"># Returned datetime can fall into missing hour.</span>
 &lt;TD&gt;     = &lt;D/DTn&gt; - &lt;D/DTn&gt;                <span class="hljs-comment"># Returns the difference. Ignores time jumps.</span>
 &lt;TD&gt;     = &lt;DTa&gt;   - &lt;DTa&gt;                  <span class="hljs-comment"># Ignores time jumps if they share tzinfo object.</span>
-&lt;TD&gt;     = &lt;TD&gt;    * &lt;real&gt;                 <span class="hljs-comment"># Also: &lt;TD&gt; = abs(&lt;TD&gt;) and &lt;TD&gt; = &lt;TD&gt; ±% &lt;TD&gt;.</span>
+&lt;TD&gt;     = &lt;TD&gt;    * &lt;int/float&gt;            <span class="hljs-comment"># Also: &lt;TD&gt; = abs(&lt;TD&gt;) and &lt;TD&gt; = &lt;TD&gt; ±% &lt;TD&gt;.</span>
 &lt;float&gt;  = &lt;TD&gt;    / &lt;TD&gt;                   <span class="hljs-comment"># How many weeks/years there are in TD. Also //.</span>
 </code></pre></div>
 
@@ -2933,7 +2932,7 @@ $ pyinstaller script.py --add-data '&lt;path&gt;:.'  <span class="hljs-comment">
  
 
   <footer>
-    <aside>July 30, 2023</aside>
+    <aside>July 31, 2023</aside>
     <a href="https://gto76.github.io" rel="author">Jure Šorn</a>
   </footer>