diff options
Diffstat (limited to 'Doc/lib/libdecimal.tex')
| -rw-r--r-- | Doc/lib/libdecimal.tex | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/Doc/lib/libdecimal.tex b/Doc/lib/libdecimal.tex index 68748f6fe7..b046aa31f6 100644 --- a/Doc/lib/libdecimal.tex +++ b/Doc/lib/libdecimal.tex @@ -448,27 +448,23 @@ active context. \begin{funcdesc}{localcontext}{\optional{c}} Return a context manager that will set the current context for - the active thread to a copy of \var{c} on entry to the with statement - and restore the previous context when exiting the with statement. If + the active thread to a copy of \var{c} on entry to the with-statement + and restore the previous context when exiting the with-statement. If no context is specified, a copy of the current context is used. + \versionadded{2.5} - For example the following code increases the current decimal precision + For example, the following code increases the current decimal precision by 42 places, performs a calculation, and then automatically restores the previous context: \begin{verbatim} from __future__ import with_statement import decimal - with decimal.localcontext() as ctx: + with localcontext() as ctx: ctx.prec = 42 # Perform a high precision calculation s = calculate_something() s = +s # Round the final result back to the default precision \end{verbatim} - - The context that is held by the context manager and made active in the - body of the \keyword{with} statement is a \emph{copy} of the context - you provide to this function, so modifying its attributes doesn't - affect anything except that temporary copy. \end{funcdesc} New contexts can also be created using the \class{Context} constructor |