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python-cheatsheet
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CSV, Memory view

pull/144/merge
Jure Šorn 6 months ago
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2 changed files with 6 additions and 6 deletions
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  1. 6
      README.md
  2. 6
      index.html

6
README.md
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@ -1834,7 +1834,7 @@ import csv
<writer>.writerows(<coll_of_coll>) # Appends multiple rows. <writer>.writerows(<coll_of_coll>) # Appends multiple rows.
``` ```
* **File must be opened with a `'newline=""'` argument, or '\r' will be added in front of every '\n' on platforms that use '\r\n' line endings!** * **File must be opened with a `'newline=""'` argument, or '\r' will be added in front of every '\n' on platforms that use '\r\n' line endings!**
* **Open existing file with `'mode="w"'` to overwrite it or `'mode="a"'` to append to it.**
* **Open existing file with `'mode="a"'` to append to it or `'mode="w"'` to overwrite it.**
### Parameters ### Parameters
* **`'dialect'` - Master parameter that sets the default values. String or a 'csv.Dialect' object.** * **`'dialect'` - Master parameter that sets the default values. String or a 'csv.Dialect' object.**
@ -2059,14 +2059,14 @@ Memory View
```python ```python
<mview> = memoryview(<bytes/bytearray/array>) # Immutable if bytes is passed, else mutable. <mview> = memoryview(<bytes/bytearray/array>) # Immutable if bytes is passed, else mutable.
<obj> = <mview>[index] # Returns int/float. Bytes if format is 'c'.
<obj> = <mview>[index] # Returns int or float. Bytes if format is 'c'.
<mview> = <mview>[<slice>] # Returns memoryview with rearranged elements. <mview> = <mview>[<slice>] # Returns memoryview with rearranged elements.
<mview> = <mview>.cast('<typecode>') # Only works between B/b/c and other types. <mview> = <mview>.cast('<typecode>') # Only works between B/b/c and other types.
<mview>.release() # Releases memory buffer of the base object. <mview>.release() # Releases memory buffer of the base object.
``` ```
```python ```python
<bytes> = bytes(<mview>) # Returns a new bytes object.
<bytes> = bytes(<mview>) # Returns a new bytes object. Also bytearray().
<bytes> = <bytes>.join(<coll_of_mviews>) # Joins memoryviews using bytes as a separator. <bytes> = <bytes>.join(<coll_of_mviews>) # Joins memoryviews using bytes as a separator.
<array> = array('<typecode>', <mview>) # Treats memoryview as a sequence of numbers. <array> = array('<typecode>', <mview>) # Treats memoryview as a sequence of numbers.
<file>.write(<mview>) # Writes `bytes(<mview>)` to the binary file. <file>.write(<mview>) # Writes `bytes(<mview>)` to the binary file.

6
index.html
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@ -1524,7 +1524,7 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
<ul> <ul>
<li><strong>File must be opened with a <code class="python hljs"><span class="hljs-string">'newline=""'</span></code> argument, or '\r' will be added in front of every '\n' on platforms that use '\r\n' line endings!</strong></li> <li><strong>File must be opened with a <code class="python hljs"><span class="hljs-string">'newline=""'</span></code> argument, or '\r' will be added in front of every '\n' on platforms that use '\r\n' line endings!</strong></li>
<li><strong>Open existing file with <code class="python hljs"><span class="hljs-string">'mode="w"'</span></code> to overwrite it or <code class="python hljs"><span class="hljs-string">'mode="a"'</span></code> to append to it.</strong></li>
<li><strong>Open existing file with <code class="python hljs"><span class="hljs-string">'mode="a"'</span></code> to append to it or <code class="python hljs"><span class="hljs-string">'mode="w"'</span></code> to overwrite it.</strong></li>
</ul> </ul>
<div><h3 id="parameters">Parameters</h3><ul> <div><h3 id="parameters">Parameters</h3><ul>
<li><strong><code class="python hljs"><span class="hljs-string">'dialect'</span></code> - Master parameter that sets the default values. String or a 'csv.Dialect' object.</strong></li> <li><strong><code class="python hljs"><span class="hljs-string">'dialect'</span></code> - Master parameter that sets the default values. String or a 'csv.Dialect' object.</strong></li>
@ -1698,14 +1698,14 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
&lt;file&gt;.write(&lt;array&gt;) <span class="hljs-comment"># Writes array's memory to binary file.</span> &lt;file&gt;.write(&lt;array&gt;) <span class="hljs-comment"># Writes array's memory to binary file.</span>
</code></pre> </code></pre>
<div><h2 id="memoryview"><a href="#memoryview" name="memoryview">#</a>Memory View</h2><p><strong>A sequence object that points to the memory of another bytes-like object. Each element can reference a single or multiple consecutive bytes, depending on format. Order and number of elements can be changed with slicing.</strong></p><pre><code class="python language-python hljs">&lt;mview&gt; = memoryview(&lt;bytes/bytearray/array&gt;) <span class="hljs-comment"># Immutable if bytes is passed, else mutable.</span> <div><h2 id="memoryview"><a href="#memoryview" name="memoryview">#</a>Memory View</h2><p><strong>A sequence object that points to the memory of another bytes-like object. Each element can reference a single or multiple consecutive bytes, depending on format. Order and number of elements can be changed with slicing.</strong></p><pre><code class="python language-python hljs">&lt;mview&gt; = memoryview(&lt;bytes/bytearray/array&gt;) <span class="hljs-comment"># Immutable if bytes is passed, else mutable.</span>
&lt;obj&gt; = &lt;mview&gt;[index] <span class="hljs-comment"># Returns int/float. Bytes if format is 'c'.</span>
&lt;obj&gt; = &lt;mview&gt;[index] <span class="hljs-comment"># Returns int or float. Bytes if format is 'c'.</span>
&lt;mview&gt; = &lt;mview&gt;[&lt;slice&gt;] <span class="hljs-comment"># Returns memoryview with rearranged elements.</span> &lt;mview&gt; = &lt;mview&gt;[&lt;slice&gt;] <span class="hljs-comment"># Returns memoryview with rearranged elements.</span>
&lt;mview&gt; = &lt;mview&gt;.cast(<span class="hljs-string">'&lt;typecode&gt;'</span>) <span class="hljs-comment"># Only works between B/b/c and other types.</span> &lt;mview&gt; = &lt;mview&gt;.cast(<span class="hljs-string">'&lt;typecode&gt;'</span>) <span class="hljs-comment"># Only works between B/b/c and other types.</span>
&lt;mview&gt;.release() <span class="hljs-comment"># Releases memory buffer of the base object.</span> &lt;mview&gt;.release() <span class="hljs-comment"># Releases memory buffer of the base object.</span>
</code></pre></div> </code></pre></div>
<pre><code class="python language-python hljs">&lt;bytes&gt; = bytes(&lt;mview&gt;) <span class="hljs-comment"># Returns a new bytes object.</span>
<pre><code class="python language-python hljs">&lt;bytes&gt; = bytes(&lt;mview&gt;) <span class="hljs-comment"># Returns a new bytes object. Also bytearray().</span>
&lt;bytes&gt; = &lt;bytes&gt;.join(&lt;coll_of_mviews&gt;) <span class="hljs-comment"># Joins memoryviews using bytes as a separator.</span> &lt;bytes&gt; = &lt;bytes&gt;.join(&lt;coll_of_mviews&gt;) <span class="hljs-comment"># Joins memoryviews using bytes as a separator.</span>
&lt;array&gt; = array(<span class="hljs-string">'&lt;typecode&gt;'</span>, &lt;mview&gt;) <span class="hljs-comment"># Treats memoryview as a sequence of numbers.</span> &lt;array&gt; = array(<span class="hljs-string">'&lt;typecode&gt;'</span>, &lt;mview&gt;) <span class="hljs-comment"># Treats memoryview as a sequence of numbers.</span>
&lt;file&gt;.write(&lt;mview&gt;) <span class="hljs-comment"># Writes `bytes(&lt;mview&gt;)` to the binary file.</span> &lt;file&gt;.write(&lt;mview&gt;) <span class="hljs-comment"># Writes `bytes(&lt;mview&gt;)` to the binary file.</span>

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