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Diffstat (limited to 'Doc/ref/ref5.tex')
| -rw-r--r-- | Doc/ref/ref5.tex | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/Doc/ref/ref5.tex b/Doc/ref/ref5.tex index ae856ff..4949d22 100644 --- a/Doc/ref/ref5.tex +++ b/Doc/ref/ref5.tex @@ -913,10 +913,13 @@ only if there exists an index \var{i} such that \code{\var{x} == \var{y}[\var{i}]} is true. For the Unicode and string types, \code{\var{x} in \var{y}} is true if -and only if there exists an index \var{i} such that \code{\var{x} == -\var{y}[\var{i}]} is true. If \code{\var{x}} is not a string or -Unicode object of length \code{1}, a \exception{TypeError} exception -is raised. +and only if \var{x} is a substring of \var{y}. An equivalent test is +\code{y.find(x) != -1}. Note, \var{x} and \var{y} need not be the +same type; consequently, \code{u'ab' in 'abc'} will return \code{True}. +Empty strings are always considered to be a substring of any other string, +so \code{"" in "abc"} will return \code{True}. +\versionchanged[Previously, \var{x} was required to be a string of +length \code{1}]{2.3} For user-defined classes which define the \method{__contains__()} method, \code{\var{x} in \var{y}} is true if and only if |