Blog
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Pandas MultiIndex: Dropping a level with reset_index(drop=True)
Your Python Pandas data frame has a multi-index, and you want to remove one part — not return it to be a regular column? Add drop=True:
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Pandas reset_index: Moving multi-index levels back to columns
Your Python Pandas data frame has a multi-index? Return selected parts to columns with the “level” keyword argument:
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Pandas reset_index: Turning a data frame’s index into a column
Return a Python Pandas data frame’s index to a regular column with reset_index: • 1-column index? It’s now a regular column.• Multi-index? Its columns are all regular columns. reset_index returns a new data frame. It doesn’t modify the original.
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Pandas set_index: Turning columns into a data frame index
Turn a column in a Python Pandas data frame into an index with set_index: Remember, set_index returns a new data frame. It doesn’t change the original one. Turn multiple columns into a multi-index by passing a list:
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Multi-line f-strings in Python: Triple quotes with interpolation
Want to include a dynamic value in a multi-line Python string? That would require both an f-string and a triple-quoted string. Good news: Python supports this!
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Python multiline strings: \n versus triple quotes
Want to include a newline in a Python string? Use \n: That’s fine for small strings. But for longer ones, use a triple-quoted string: BTW, the created strings are the same:
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Python string quotes: Handling an apostrophe inside a string
A classic Python mistake: What’s wrong with this code? The string uses ” as delimiters. But it also contains a ‘ inside. Solutions:
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Reading binary files in Python: Use ‘rb’ mode to get bytes
Want to read a non-text file with Python? Specify “rb”, for “read binary,” to avoid errors. What is t? A *byte* string, not a regular text string.
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functools.total_ordering: Define two comparison methods, get six
Python tip: Don’t write all 6 comparison methods! Define __eq__ and __lt__, then add @total_ordering: You get >, >=, <= for free!
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Python `__all__`: Blocking wildcard imports with a fake name
Want to guarantee that no one can run “from .. import *” on your Python module? Include a non-existent name in the __all__ list: Using “from .. import *” on this module will result in an error!