评价'not (False and True)'

Question

我遇到了这个例子（"Hacking Secret Ciphers with Python"，p135），我很困惑：

not (False and True)

该示例指出它的计算结果为 False，但我不明白为什么。如果括号修改了优先级，那么我们肯定正在评估：

not (False)

计算结果为 True，不是吗？还是我遗漏了什么？

// output functions are configurable.  This one just appends some text
// to a pre element.
function outf(text) {
  var mypre = document.getElementById("output");
  mypre.innerHTML = mypre.innerHTML + text;
}

function builtinRead(x) {
  if (Sk.builtinFiles === undefined || Sk.builtinFiles["files"][x] === undefined)
    throw "File not found: '" + x + "'";
  return Sk.builtinFiles["files"][x];
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// Here's everything you need to run a python program in skulpt
// grab the code from your textarea
// get a reference to your pre element for output
// configure the output function
// call Sk.importMainWithBody()
function runit() {
  var prog = document.getElementById("yourcode").value;
  var mypre = document.getElementById("output");
  mypre.innerHTML = '';
  Sk.pre = "output";
  Sk.configure({
    output: outf,
    read: builtinRead
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  (Sk.TurtleGraphics || (Sk.TurtleGraphics = {})).target = 'mycanvas';
  var myPromise = Sk.misceval.asyncToPromise(function() {
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}

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js" type="text/javascript"></script>
<script src="http://www.skulpt.org/static/skulpt.min.js" type="text/javascript"></script>
<script src="http://www.skulpt.org/static/skulpt-stdlib.js" type="text/javascript"></script>

<h3>Try This</h3> 
<form>
  <textarea id="yourcode" cols="40" rows="10">print(not (False and True))
  </textarea>
  <br />
  <button type="button" onclick="runit()">Run</button>
</form>
<pre id="output"></pre> 
<!-- If you want turtle graphics include a canvas -->
<div id="mycanvas"></div>

Answer 1

not (False and True) 肯定是 True，如果您在 Python REPL 中键入表达式，您会看到这一点。谁声称它是 False？

Answer 2

这实际上涵盖在the errata:

Page 135, the interactive shell should look like this:
>>> not False and False # not False evaluates first 
True 
>>> not (False and False) # (False and False) evaluates first 
False 
(Thanks to Omer Chohan)

已在 the online version of the chapter 中更正，但 PDF 中没有。

评价'not (False and True)'

Evaluation of 'not (False and True)'

python

boolean

python-3.x