diff --git a/pdf/index_for_pdf.html b/pdf/index_for_pdf.html
index 86a2722bb..735f3c206 100644
--- a/pdf/index_for_pdf.html
+++ b/pdf/index_for_pdf.html
@@ -25,12 +25,12 @@ <h3 id="c">C</h3>
 <strong>collections module, <a href="#dictionary">2</a>, <a href="#namedtuple">3</a>, <a href="#abstractbaseclasses">4</a>, <a href="#abcsequence">19</a>, <a href="#deque">29</a></strong><br>
 <strong>combinatorics, <a href="#combinatorics">8</a></strong><br>
 <strong>command line arguments, <a href="#commandlinearguments">22</a></strong><br>
-<strong>comprehensions, <a href="#comprehensions">11</a></strong><br>
+<strong>comprehensions, <a href="#list">1</a>, <a href="#dictionary">2</a>, <a href="#comprehensions">11</a></strong><br>
 <strong>context manager, <a href="#contextmanager">17</a>, <a href="#readtextfromfile">23</a>, <a href="#or">27</a>, <a href="#or-1">32</a></strong><br>
 <strong>copy function, <a href="#copy">15</a></strong><br>
 <strong>coroutine, <a href="#coroutines">33</a></strong><br>
 <strong>counter, <a href="#counter">2</a>, <a href="#generator">4</a>, <a href="#nonlocal">12</a>, <a href="#iterator-1">17</a></strong><br>
-<strong>csv, <a href="#csv">26</a>, <a href="#printsacsvspreadsheettotheconsole">34</a>, <a href="#dataframeencodedecode">46</a>, <a href="#displaysalinechartoftotalcoronavirusdeathspermilliongroupedbycontinent">47</a></strong><br>
+<strong>csv, <a href="#csv">26</a>, <a href="#printsacsvspreadsheettotheconsole">34</a>, <a href="#fileformats">46</a>, <a href="#displaysalinechartoftotalcoronavirusdeathspermilliongroupedbycontinent">47</a></strong><br>
 <strong>curses module, <a href="#runsaterminalgamewhereyoucontrolanasteriskthatmustavoidnumbers">33</a>, <a href="#consoleapp">34</a></strong><br>
 <strong>cython, <a href="#typeannotations">15</a>, <a href="#cython">49</a></strong>  </p>
 <h3 id="d">D</h3>
@@ -43,11 +43,11 @@ <h3 id="d">D</h3>
 <h3 id="e">E</h3>
 <p><strong>enum module, <a href="#enum">19</a>-<a href="#inline-1">20</a></strong><br>
 <strong>enumerate function, <a href="#enumerate">3</a></strong><br>
-<strong>excel, <a href="#dataframeencodedecode">46</a></strong><br>
+<strong>excel, <a href="#fileformats">46</a></strong><br>
 <strong>exceptions, <a href="#exceptions">20</a>-<a href="#exceptionobject">21</a>, <a href="#exceptions-1">23</a>, <a href="#logging">31</a></strong><br>
 <strong>exit function, <a href="#exit">21</a></strong>  </p>
 <h3 id="f">F</h3>
-<p><strong>files, <a href="#print">22</a>-<a href="#memoryview">29</a>, <a href="#runsabasicfileexplorerintheconsole">34</a>, <a href="#dataframeencodedecode">46</a></strong><br>
+<p><strong>files, <a href="#print">22</a>-<a href="#memoryview">29</a>, <a href="#runsabasicfileexplorerintheconsole">34</a>, <a href="#fileformats">46</a></strong><br>
 <strong>filter function, <a href="#mapfilterreduce">11</a></strong><br>
 <strong>flask library, <a href="#webapp">36</a></strong><br>
 <strong>floats, <a href="#abstractbaseclasses">4</a>, <a href="#floats">6</a>, <a href="#numbers">7</a></strong><br>
@@ -73,7 +73,7 @@ <h3 id="i">I</h3>
 <strong>iterator, <a href="#enumerate">3</a>-<a href="#generator">4</a>, <a href="#comprehensions">11</a>, <a href="#iterator-1">17</a></strong><br>
 <strong>itertools module, <a href="#itertools">3</a>, <a href="#combinatorics">8</a></strong>  </p>
 <h3 id="j">J</h3>
-<p><strong>json, <a href="#json">25</a>, <a href="#restrequest">36</a>, <a href="#dataframeencodedecode">46</a></strong>  </p>
+<p><strong>json, <a href="#json">25</a>, <a href="#restrequest">36</a>, <a href="#fileformats">46</a></strong>  </p>
 <h3 id="l">L</h3>
 <p><strong>lambda, <a href="#lambda">11</a></strong><br>
 <strong>lists, <a href="#list">1</a>-<a href="#list">2</a>, <a href="#abstractbaseclasses">4</a>, <a href="#otheruses">11</a>, <a href="#sequence">18</a>-<a href="#abcsequence">19</a>, <a href="#collectionsandtheirexceptions">21</a></strong><br>
@@ -119,14 +119,14 @@ <h3 id="r">R</h3>
 <strong>requests library, <a href="#scrapespythonsurlandlogofromitswikipediapage">35</a>, <a href="#startstheappinitsownthreadandqueriesitsrestapi">36</a></strong>  </p>
 <h3 id="s">S</h3>
 <p><strong>scope, <a href="#insidefunctiondefinition">10</a>, <a href="#nonlocal">12</a>, <a href="#complexexample">20</a></strong><br>
-<strong>scraping, <a href="#scraping">35</a>, <a href="#basicmariobrothersexample">43</a>, <a href="#dataframeencodedecode">46</a>, <a href="#displaysalinechartoftotalcoronavirusdeathspermilliongroupedbycontinent">47</a>-<a href="#displaysamultiaxislinechartoftotalcoronaviruscasesandchangesinpricesofbitcoindowjonesandgold">48</a></strong><br>
+<strong>scraping, <a href="#scraping">35</a>, <a href="#basicmariobrothersexample">43</a>, <a href="#fileformats">46</a>, <a href="#displaysalinechartoftotalcoronavirusdeathspermilliongroupedbycontinent">47</a>-<a href="#displaysamultiaxislinechartoftotalcoronaviruscasesandchangesinpricesofbitcoindowjonesandgold">48</a></strong><br>
 <strong>sequence, <a href="#abstractbaseclasses">4</a>, <a href="#sequence">18</a>-<a href="#abcsequence">19</a></strong><br>
 <strong>sets, <a href="#set">2</a>, <a href="#abstractbaseclasses">4</a>, <a href="#otheruses">11</a>, <a href="#tableofrequiredandautomaticallyavailablespecialmethods">19</a>, <a href="#collectionsandtheirexceptions">21</a></strong><br>
 <strong>shell commands, <a href="#shellcommands">25</a></strong><br>
 <strong>sleep function, <a href="#progressbar">34</a></strong><br>
 <strong>sortable, <a href="#list">1</a>, <a href="#sortable">16</a></strong><br>
 <strong>splat operator, <a href="#splatoperator">10</a>-<a href="#otheruses">11</a>, <a href="#readrowsfromcsvfile">26</a></strong><br>
-<strong>sql, <a href="#sqlite">27</a>, <a href="#dataframeencodedecode">46</a></strong><br>
+<strong>sql, <a href="#sqlite">27</a>, <a href="#fileformats">46</a></strong><br>
 <strong>statistics, <a href="#statistics">7</a>, <a href="#numpy">37</a>-<a href="#indexing">38</a>, <a href="#pandas">44</a>-<a href="#displaysamultiaxislinechartoftotalcoronaviruscasesandchangesinpricesofbitcoindowjonesandgold">48</a></strong><br>
 <strong>strings, <a href="#abstractbaseclasses">4</a>-<a href="#comparisonofpresentationtypes">7</a>, <a href="#class">14</a></strong><br>
 <strong>struct module, <a href="#struct">28</a>-<a href="#integertypesuseacapitalletterforunsignedtypeminimumandstandardsizesareinbrackets">29</a></strong><br>
diff --git a/pdf/index_for_pdf_print.html b/pdf/index_for_pdf_print.html
index 41ecf8940..5c20dd81a 100644
--- a/pdf/index_for_pdf_print.html
+++ b/pdf/index_for_pdf_print.html
@@ -25,7 +25,7 @@ <h3 id="c">C</h3>
 <strong>collections module, 2, 3, 4, 19, 29</strong><br>
 <strong>combinatorics, 8</strong><br>
 <strong>command line arguments, 22</strong><br>
-<strong>comprehensions, 11</strong><br>
+<strong>comprehensions, 1, 2, 11</strong><br>
 <strong>context manager, 17, 23, 27, 32</strong><br>
 <strong>copy function, 15</strong><br>
 <strong>coroutine, 33</strong><br>