Some IPython tricks

English version of talk presented at local Python user group in Florianopolis

Transcript

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3. X
   

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4. $ ipython profile create
   [ProfileCreate] Generating default config file: u'~/.
   ipython/profile_default/ipython_config.py'
   $ vim ~/.ipython/profile_default/ipython_config.py
   c = get_config()
   c.TerminalIPythonApp.display_banner = False
   c.TerminalInteractiveShell.colors = 'Linux'
   c.TerminalInteractiveShell.separate_in = ''
   c.TerminalInteractiveShell.confirm_exit = False
   c.TerminalInteractiveShell.term_title = True
   c.PromptManager.out_template = ''
   c.PromptManager.in2_template = ' '
   c.PromptManager.in_template = '>>> '
   $ ipython
   >>> print '\o/'
   \o/
   

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6. >>> from json import
   JSONDecoder _default_encoder dumps loads
   JSONEncoder decoder encoder scanner
   _default_decoder dump load tool
   >>> from json import dump
   dump dumps
   >>> from xml.
   xml.dom xml.etree xml.parsers xml.sax
   >>> from xml.dom.
   xml.dom.NodeFilter xml.dom.expatbuilder xml.dom.minidom xml.dom.xmlbuilder
   xml.dom.domreg xml.dom.minicompat xml.dom.pulldom
   

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7. >>> d = {
   'url': 'http://news.ycombinator.com',
   'title': 'Hacker News',
   'last_visit': '2016-01-17'
   }
   >>> d[
   d['last_visit'] d['title'] d['url']
   >>> d['url']
   'http://news.ycombinator.com'
   

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8. >>> l = ["hello", [1, 2, 3]]
   >>> l[0].
   l[0].capitalize l[0].isalnum l[0].lstrip l[0].splitlines
   l[0].center l[0].isalpha l[0].partition l[0].startswith
   l[0].count l[0].isdigit l[0].replace l[0].strip
   l[0].decode l[0].islower l[0].rfind l[0].swapcase
   l[0].encode l[0].isspace l[0].rindex l[0].title
   ...
   >>> l[1].
   l[1].append l[1].extend l[1].insert l[1].remove l[1].sort
   l[1].count l[1].index l[1].pop l[1].reverse
   >>> '1,2,3'.split(',').
   '1,2,3'.split(',').append '1,2,3'.split(',').pop
   '1,2,3'.split(',').count '1,2,3'.split(',').remove
   '1,2,3'.split(',').extend '1,2,3'.split(',').reverse
   ...
   Enable greedy completion in profile:
   c.IPCompleter.greedy = True
   

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10. >>> import os
    >>> os.path.join?
    Type: function
    String form:
    File: /usr/lib/python2.7/posixpath.py
    Definition: os.path.join(a, *p)
    Docstring:
    Join two or more pathname components, inserting '/' as needed.
    If any component is an absolute path, all previous path components
    will be discarded. An empty last part will result in a path that
    ends with a separator.
    >>>
    

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11. >>> os.path.join??
    Type: function
    String form:
    File: /usr/lib/python2.7/posixpath.py
    Definition: os.path.join(a, *p)
    Source:
    def join(a, *p):
    """Join two or more pathname components, inserting '/' as needed.
    If any component is an absolute path, all previous path components
    will be discarded. An empty last part will result in a path that
    ends with a separator."""
    path = a
    for b in p:
    <... resto do código omitido ...>
    

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13. >>> 12 + 22
    34
    >>> 13 + 9 + 4
    26
    >>> _ + __
    60
    >>> result = _ # no need to re-run code =)
    

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14. >>> 12 + 22
    34
    >>> 13 + 9 + 4
    26
    >>> _ + __
    60
    >>> result = _ # no need to re-run code =)
    >>> _1
    34
    >>> _2
    26
    

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15. c.TerminalInteractiveShell.cache_size = 0
    The above setting disables _
    _, __ and ___ will still work
    Ref: https://ipython.org/ipython-doc/3/interactive/reference.html#output-caching-system
    

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17. >>> lista = list(range(1000))
    >>> %timeit map(str, lista)
    10000 loops, best of 3: 74.5 µs per
    loop
    >>> %timeit [str(l) for l in lista]
    10000 loops, best of 3: 121 µs per loop
    >>>
    >>> import math
    >>> %time math.sqrt(3.456)
    CPU times: user 0 ns, sys: 0 ns, total:
    0 ns
    Wall time: 13.1 µs
    1.85903200617956
    %time runs only once and shows
    the result
    (much like the Bash time builtin)
    

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19. >>> import os
    >>> bashrc = os.path.expanduser('~/.
    bashrc')
    >>> open(bashrc, 'w').write('echo
    muhaha')
    >>> %hist
    import os
    bashrc = os.path.expanduser('~/.
    bashrc')
    open(bashrc, 'w').write('echo muhaha')
    %hist
    >>> %hist -f arquivo.py
    >>> # or yet:
    >>> %save arquivo.py 1-3
    

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20. ○
    ○
    ○
    ○
    ○
    

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22. >>> def double_loop(collection):
    ...: for e in collection:
    ...: print(e)
    ...: for e in collection:
    ...: print(e)
    ...:
    File "", line 4
    for e in collection:
    ^
    IndentationError: unindent does not match any outer indentation level
    If you want to paste code into IPython, try the %paste and %cpaste magic functions.
    >>>
    

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23. >>> %paste
    def double_loop(collection):
    for e in collection:
    print(e)
    for e in collection:
    print(e)
    ## -- End pasted text --
    >>>
    Works like Ctrl-V or Cmd-
    V, but doesn’t always work
    -- it needs bindings to
    desktop libraries
    

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24. >>> %autoindent
    Automatic indentation is: OFF
    >>> def double_loop(collection):
    ....: for e in collection:
    ....: print(e)
    ....: for e in collection:
    ....: print(e)
    ....:
    >>>
    

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25. >>> %cpaste
    Pasting code; enter '--' alone on the line to stop or use Ctrl-D.
    :
    

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26. >>> %cpaste
    Pasting code; enter '--' alone on the line to stop or use Ctrl-D.
    :def loop_duplo(collection):
    : for e in collection:
    : print(e)
    : for e in collection:
    : print(e)
    :
    :
    >>>
    

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28. >>> >>> import math
    >>> >>> for n in [9, 6, 25]:
    ....: ...: print(math.sqrt(n))
    ....: ...:
    3.0
    2.44948974278
    5.0
    >>>
    Note how the extra markup got
    ignored
    

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30. (env)$ ipython
    WARNING: Attempting to work in a virtualenv. If
    you encounter problems, please install IPython
    inside the virtualenv.
    (env)$ pip install ipython
    (env)$ ipython
    WARNING: Attempting to work in a virtualenv. If
    you encounter problems, please install IPython
    inside the virtualenv.
    (env)$ hash -r
    (env)$ ipython
    >>> print "Yay!"
    Yay!
    

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32. >>> !ls
    a.out file1.txt file2.txt
    >>> files = !ls
    >>> files
    ['a.out', 'file1.txt', 'file2.txt']
    >>> files.s
    'a.out file1.txt file2.txt'
    >>> files.grep('\d')
    ['file1.txt', 'file2.txt']
    

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34. from IPython import embed; embed()
    

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35. Questions?
    

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