Importing again and again | Thread profile

If I have code which imports a module over and over again...say each time a function is called, does that cause Python to actually re-import it...or will it skip it once the module has been imported?? for example: def foo(): import bar bar.printStuff() foo() foo() foo() foo() ....will that re-import bar 4 times...or just import it once? is this a big performance hit? thanks

abcd wrote: > If I have code which imports a module over and over again...say each > time a function is called, does that cause Python to actually re-import > it...or will it skip it once the module has been imported?? > > for example: > > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? is this a > big ...

abcd wrote: > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? is this a > big performance hit? > > thanks > Given a file called bar.py with the following contents: print "I'm being imported!" def printStuff(): print 'stuff' I get this output when I import foo.py: >>> import foo I'm being imported! ...

abcd írta: > If I have code which imports a module over and over again...say each > time a function is called, does that cause Python to actually re-import > it...or will it skip it once the module has been imported?? > > for example: > > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? Just once. Try ...

"abcd" wrote: > If I have code which imports a module over and over again...say each > time a function is called, does that cause Python to actually re-import > it...or will it skip it once the module has been imported?? > > for example: > > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? is this a > ...

"John Bokma" wrote in message news:Xns97DCA4EEBEBEEcastleamber@130.133.1.4... >> def foo(): >> import bar >> bar.printStuff() > I am new to Python so this might be a weird question, but it there a > reason why you import bar inside foo? Two possible reasons: 1) delay import until actually needed, if ever. 2) put 'bar' into the function local namespace instead of the module global namespace ...

"Terry Reedy" wrote: > > "John Bokma" wrote in message > news:Xns97DCA4EEBEBEEcastleamber@130.133.1.4... >>> def foo(): >>> import bar >>> bar.printStuff() >> I am new to Python so this might be a weird question, but it there a >> reason why you import bar inside foo? > > Two possible reasons: > 1) delay import until actually needed, if ever. > 2) put 'bar' into the function local namespace ...

it's import-ed only once # magic.py file #!/usr/bin/python print "here" import magic # try to import itself then try # bad_magic.py #!/usr/bin/python print "here" import bad_magic reload(bad_magic) hth, Daniel

abcd wrote: > If I have code which imports a module over and over again...say each > time a function is called, does that cause Python to actually re-import > it...or will it skip it once the module has been imported?? > > for example: > > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? is this a > big ...

Le Jeudi 08 Juin 2006 22:02, abcd a écrit*: > > def foo(): > import bar > bar.printStuff() > > foo() > foo() > foo() > foo() > > ...will that re-import bar 4 times...or just import it once? is this a > big performance hit? Import a module more than once doesn't execute the code of this module more than once. I don't know what's your need but as some have spoke of reload I just want to warn you,...