Thursday, April 24, 2014

py - convert sequence of obj to strings then concat

P60 [[cookbook]] shows a neat trick

>>> data = ['aa', 50, 91.1]
>>> ', ' . join(str(d) for d in data)
'aa, 50, 91.1'

Technique: generator expression,
Technique: str() conversion ctor. Without conversion, joining string with non-string leads to exceptions.
Technique: calling join() method on the delimiter string

The author points out that string concat can be very inefficient if you blindly use "+" operator. Similarly, java/dotnet offers stringBuilders, and c++ offers stringstream

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