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Diffstat (limited to 'Doc/ref')
| -rw-r--r-- | Doc/ref/ref5.tex | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/Doc/ref/ref5.tex b/Doc/ref/ref5.tex index db98fe4..6b699bc 100644 --- a/Doc/ref/ref5.tex +++ b/Doc/ref/ref5.tex @@ -152,13 +152,22 @@ A list display is a possibly empty series of expressions enclosed in square brackets: \begin{verbatim} -list_display: "[" [expression_list] "]" +list_display: "[" [expression_list [list_iter]] "]" +list_iter: list_for | list_if +list_for: "for" expression_list "in" testlist [list_iter] +list_if: "if" test [list_iter] \end{verbatim} -A list display yields a new list object. If it has no expression -list, the list object has no items. Otherwise, the elements of the -expression list are evaluated from left to right and inserted in the -list object in that order. +A list display yields a new list object. Its contents are specified +by providing either a list of expressions or a list comprehension. +When a comma-separated list of expressions is supplied, its elements are +evaluated from left to right and placed into the list object in that +order. When a list comprehension is supplied, it consists of a +single expression followed by one or more "for" or "if" clauses. In this +case, the elements of the new list are those that would be produced +by considering each of the "for" or "if" clauses a block, nesting from +left to right, and evaluating the expression to produce a list element +each time the innermost block is reached. \obindex{list} \indexii{empty}{list} |