How to concatenate (join) items in a list to a single string

How do I concatenate a list of strings into a single string?

For example, given ['this', 'is', 'a', 'sentence'], how do I get "this-is-a-sentence"?

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_{For handling a few strings in separate variables, see How do I append one string to another in Python?.}

_{For the opposite process - creating a list from a string - see How do I split a string into a list of characters? or How do I split a string into a list of words? as appropriate.}