@ -54,7 +54,7 @@
< body >
< header >
< aside > June 9 , 2023< / aside >
< aside > June 30 , 2023< / aside >
< a href = "https://gto76.github.io" rel = "author" > Jure Šorn< / a >
< / header >
@ -1609,14 +1609,14 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
< span class = "hljs-keyword" > with< / span > < conn> .begin(): ... < span class = "hljs-comment" > # Exits the block with commit or rollback.< / span >
< / code > < / pre > < / div >
< pre > < code class = "text language-text" > ┏━━━━━━━━━━━━┯━━━━━━━━━━━━━━┯━━━━━━━━━━━ ┯━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Dialect │ pip3 install │ import │ Dependencies ┃
┠────────────┼──────────────┼─────────── ┼──────────────────────────────────┨
┃ mysql │ mysqlclient │ MySQLdb │ www.pypi.org/project/mysqlclient ┃
┃ postgresql │ psycopg2 │ psycopg2 │ www.pypi.org/project/psycopg2 ┃
┃ mssql │ pyodbc │ pyodbc │ www.pypi.org/project/pyodbc ┃
┃ oracle │ oracledb │ oracledb │ www.pypi.org/project/oracledb ┃
┗━━━━━━━━━━━━┷━━━━━━━━━━━━━━┷━━━━━━━━━━━ ┷━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
< pre > < code class = "text language-text" > ┏━━━━━━━━━━━━┯━━━━━━━━━━━━━━┯━━━━━━━━━━┯━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Dialect │ pip3 install │ import │ Dependencies ┃
┠────────────┼──────────────┼──────────┼──────────────────────────────────┨
┃ mysql │ mysqlclient │ MySQLdb │ www.pypi.org/project/mysqlclient ┃
┃ postgresql │ psycopg2 │ psycopg2 │ www.pypi.org/project/psycopg2 ┃
┃ mssql │ pyodbc │ pyodbc │ www.pypi.org/project/pyodbc ┃
┃ oracle │ oracledb │ oracledb │ www.pypi.org/project/oracledb ┃
┗━━━━━━━━━━━━┷━━━━━━━━━━━━━━┷━━━━━━━━━━┷━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
< / code > < / pre >
< div > < h2 id = "bytes" > < a href = "#bytes" name = "bytes" > #< / a > Bytes< / h2 > < p > < strong > Bytes object is an immutable sequence of single bytes. Mutable version is called bytearray.< / strong > < / p > < pre > < code class = "python language-python hljs" > < bytes> = < span class = "hljs-string" > b'< str> '< / span > < span class = "hljs-comment" > # Only accepts ASCII characters and \x00-\xff.< / span >
< int> = < bytes> [< index> ] < span class = "hljs-comment" > # Returns an int in range from 0 to 255.< / span >
@ -2124,44 +2124,43 @@ duration_in_seconds = perf_counter() - start_time
< / code > < / pre > < / div >
< div > < h3 id = "timingasnippet" > Timing a Snippet< / h3 > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > < span class = "hljs-keyword" > from< / span > timeit < span class = "hljs-keyword" > import< / span > timeit
< span class = "hljs-meta" > > > > < / span > timeit(< span class = "hljs-string" > "''.join(str(i) for i in range(100))"< / span > ,
< span class = "hljs-meta" > ... < / span > number=< span class = "hljs-number" > 10000< / span > , globals=globals(), setup=< span class = "hljs-string" > 'pass'< / span > )
< span class = "hljs-number" > 0.34986< / span >
< / code > < / pre > < / div >
< div > < h3 id = "profilingbyline" > Profiling by Line< / h3 > < pre > < code class = "python language-python hljs" > < span class = "hljs-comment" > # $ pip3 install line_profiler memory_profiler< / span >
< span class = "hljs-meta" > @profile< / span >
< span class = "hljs-function" > < span class = "hljs-keyword" > def< / span > < span class = "hljs-title" > main< / span > < span class = "hljs-params" > ()< / span > :< / span >
a = [*range(< span class = "hljs-number" > 10000< / span > )]
b = {*range(< span class = "hljs-number" > 10000< / span > )}
main()
< / code > < / pre > < / div >
< pre > < code class = "text language-text" > $ kernprof -lv test.py
< span class = "hljs-meta" > > > > < / span > timeit(< span class = "hljs-string" > 'list(range(10000))'< / span > , number=< span class = "hljs-number" > 1000< / span > , globals=globals(), setup=< span class = "hljs-string" > 'pass'< / span > )
< span class = "hljs-number" > 0.19373< / span >
< / code > < / pre > < / div >
< div > < h3 id = "profilingbyline" > Profiling by Line< / h3 > < pre > < code class = "text language-text" > $ pip3 install line_profiler
$ echo "
@profile
def main():
a = list(range(10000))
b = set(range(10000))
main()" > test.py
$ kernprof -lv test.py
Line # Hits Time Per Hit % Time Line Contents
=======================================================
1 @profile
2 def main():
3 1 955.0 955.0 43.7 a = [*range(10000)]
4 1 1231.0 1231.0 56.3 b = {*range(10000)}
$ python3 -m memory_profiler test.py
Line # Mem usage Increment Line Contents
=======================================================
1 37.668 MiB 37.668 MiB @profile
2 def main():
3 38.012 MiB 0.344 MiB a = [*range(10000)]
4 38.477 MiB 0.465 MiB b = {*range(10000)}
< / code > < / pre >
< div > < h3 id = "callgraph" > Call Graph< / h3 > < div > < h4 id = "generatesapngimageofthecallgraphwithhighlightedbottlenecks" > Generates a PNG image of the call graph with highlighted bottlenecks:< / h4 > < pre > < code class = "python language-python hljs" > < span class = "hljs-comment" > # $ pip3 install pycallgraph2; apt/brew install graphviz< / span >
< span class = "hljs-keyword" > import< / span > pycallgraph2 < span class = "hljs-keyword" > as< / span > cg, datetime
3 1 219.0 219.0 31.1 a = list(range(10000))
4 1 487.0 487.0 68.9 b = set(range(10000))
< / code > < / pre > < / div >
filename = < span class = "hljs-string" > f'profile-< span class = "hljs-subst" > {datetime.datetime.now():%Y%m%d_%H%M%S}< / span > .png'< / span >
drawer = cg.output.GraphvizOutput(output_file=filename)
< span class = "hljs-keyword" > with< / span > cg.PyCallGraph(drawer):
< code_to_be_profiled>
< / code > < / pre > < / div > < / div >
< div > < h3 id = "callandflamegraphs" > Call and Flame Graphs< / h3 > < pre > < code class = "bash language-bash hljs" > $ pip3 install gprof2dot snakeviz
$ apt/brew install graphviz
$ python3 -m cProfile -o test.prof test.py
$ gprof2dot -f pstats test.prof | dot -Tpng -o test.png; xdg-open/open test.png
$ snakeviz test.prof
< / code > < / pre > < / div >
< div > < h3 id = "samplingandmemoryprofilers" > Sampling and Memory Profilers< / h3 > < pre > < code class = "text language-text" > ┏━━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━┯━━━━━━━━━━┯━━━━━━┓
┃ pip3 install │ How to run │ Target │ Type │ Live ┃
┠──────────────┼───────────────────────────────┼────────────┼──────────┼──────┨
┃ py-spy │ py-spy top -- python3 test.py │ CPU │ Sampling │ Yes ┃
┃ pyinstrument │ pyinstrument test.py │ CPU │ Sampling │ No ┃
┃ scalene │ scalene test.py │ CPU+Memory │ Sampling │ No ┃
┃ memray │ memray run --live test.py │ Memory │ Tracing │ Yes ┃
┃ filprofiler │ fil-profile run test.py │ Memory │ Tracing │ No ┃
┗━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┷━━━━━━━━━━━━┷━━━━━━━━━━┷━━━━━━┛
< / code > < / pre > < / div >
< div > < h2 id = "numpy" > < a href = "#numpy" name = "numpy" > #< / a > NumPy< / h2 > < p > < strong > Array manipulation mini-language. It can run up to one hundred times faster than the equivalent Python code. An even faster alternative that runs on a GPU is called CuPy.< / strong > < / p > < pre > < code class = "python language-python hljs" > < span class = "hljs-comment" > # $ pip3 install numpy< / span >
< span class = "hljs-keyword" > import< / span > numpy < span class = "hljs-keyword" > as< / span > np
@ -2934,7 +2933,7 @@ $ pyinstaller script.py --add-data '<path>:.' <span class="hljs-comment">
< footer >
< aside > June 9 , 2023< / aside >
< aside > June 30 , 2023< / aside >
< a href = "https://gto76.github.io" rel = "author" > Jure Šorn< / a >
< / footer >
Jure Šorn
1 year ago