Re: getting the size of an object
On 6/18/07, filox <[EMAIL PROTECTED]> wrote: > is there a way to find out the size of an object in Python? e.g., how could > i get the size of a list or a tuple? mxTools includes a sizeof() function. Never used it myself, but MAL isn't notorious for getting things wrong, so I'm sure it does what it says on the tin. http://tinyurl.com/3ybdb3 Cheers, Simon B. [EMAIL PROTECTED] http://www.brunningonline.net/simon/blog/ GTalk: simon.brunning | MSN: small_values | Yahoo: smallvalues -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
En Mon, 18 Jun 2007 16:48:36 -0300, filox <[EMAIL PROTECTED]> escribió: > "Brett Hoerner" <[EMAIL PROTECTED]> wrote in message >> Although I have the feeling you mean "how many bytes does this object >> take in memory" - and I believe the short answer is no. > > is there a long answer? what i want is to find out the number of bytes > the > object takes up in memory (during runtime). since python has a lot of > introspection mechanisms i thought that should be no problem... Consider this: x = "x" * 100 x is a string taking roughly 1MB of memory. y = x y is a string taking roughly 1MB of memory *but* it is shared, in fact it is the same object. So you can't add them to get the total memory usage. z = (x,y) z takes just a few bytes: a pointer to x, to y, to its own type, its reference count. The total memory for the three objects is a few bytes more than 1MB. For arbitrary objects, a rough estimate may be its pickle size: len(dumps(x)) == 108 len(dumps(y)) == 108 len(dumps(z)) == 116 -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
On Jun 19, 9:00 am, 7stud <[EMAIL PROTECTED]> wrote: > On Jun 18, 10:07 am, "filox" <[EMAIL PROTECTED]> wrote: > > > is there a way to find out the size of an object in Python? e.g., how could > > i get the size of a list or a tuple? > > > -- > > You're never too young to have a Vietnam flashback > > You can use the struct module to find the size in bytes: > > import struct > > mylist = [10, 3.7, "hello"] > > int_count = 0 > float_count = 0 > char_count = 0 > > for elmt in mylist: > if type(elmt) == int: > int_count += 1 > elif type(elmt) == float: > float_count += 1 > elif type(elmt) == str: > char_count += len(elmt) > > format_string = "%di%dd%dc" % (int_count, float_count, char_count) > list_size_in_bytes = struct.calcsize(format_string) > print list_size_in_bytes > > --output:-- > 17 That would give you the size taken up by the values. However each object has in addition to its value, a pointer to its type, and a reference count -- together an extra 8 bytes each on a 32-bit CPython implementation. A second problem is that your calculation doesn't allow for the interning of some str values and some int values. A third problem is that it caters only for int, float and str elements -- others count for nothing. -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
On Jun 18, 10:07 am, "filox" <[EMAIL PROTECTED]> wrote: > is there a way to find out the size of an object in Python? e.g., how could > i get the size of a list or a tuple? > > -- > You're never too young to have a Vietnam flashback You can use the struct module to find the size in bytes: import struct mylist = [10, 3.7, "hello"] int_count = 0 float_count = 0 char_count = 0 for elmt in mylist: if type(elmt) == int: int_count += 1 elif type(elmt) == float: float_count += 1 elif type(elmt) == str: char_count += len(elmt) format_string = "%di%dd%dc" % (int_count, float_count, char_count) list_size_in_bytes = struct.calcsize(format_string) print list_size_in_bytes --output:-- 17 -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
filox wrote: > "Brett Hoerner" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] >> On Jun 18, 11:07 am, "filox" <[EMAIL PROTECTED]> wrote: >>> is there a way to find out the size of an object in Python? e.g., how >>> could >>> i get the size of a list or a tuple? >> "Size" can mean a lot of things, >> >> len(my_list) >> len(my_tuple) >> >> Although I have the feeling you mean "how many bytes does this object >> take in memory" - and I believe the short answer is no. >> > > is there a long answer? what i want is to find out the number of bytes the > object takes up in memory (during runtime). since python has a lot of > introspection mechanisms i thought that should be no problem... > > New-style classes have both a __basicsize__ and an __itemsize__ attribute. __basicsize__ gives the number of bytes in the fixed size portion of an instance. For immutable types with variable size, such as tuple and str, multiply __itemsize__ by the object length and add to __basicsize__ to get the instance size. long type instances also vary in length, but since long has no length property trying to figure out the size of a particular instance is harder. And types like list, map and unicode keep pointers to blocks of memory allocated separately. -- Lenard Lindstrom <[EMAIL PROTECTED]> -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
On Jun 18, 2:48 pm, "filox" <[EMAIL PROTECTED]> wrote: > is there a long answer? what i want is to find out the number of bytes the > object takes up in memory (during runtime). since python has a lot of > introspection mechanisms i thought that should be no problem... There isn't an automatic way through the language afaik. I think allocating memory in order to keep track of how much memory you have allocated can begin to be a problem. And most people just don't care down to each and every byte. :) Some helpful information here: http://groups.google.com/group/comp.lang.python/browse_thread/thread/a7b9f3c03fb49aa/0e793beec82884f0?lnk=gst&q=size+object&rnum=4#0e793beec82884f0 Brett -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
"Brett Hoerner" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > On Jun 18, 11:07 am, "filox" <[EMAIL PROTECTED]> wrote: >> is there a way to find out the size of an object in Python? e.g., how >> could >> i get the size of a list or a tuple? > > "Size" can mean a lot of things, > > len(my_list) > len(my_tuple) > > Although I have the feeling you mean "how many bytes does this object > take in memory" - and I believe the short answer is no. > is there a long answer? what i want is to find out the number of bytes the object takes up in memory (during runtime). since python has a lot of introspection mechanisms i thought that should be no problem... -- You're never too young to have a Vietnam flashback -- http://mail.python.org/mailman/listinfo/python-list
Re: getting the size of an object
On Jun 18, 11:07 am, "filox" <[EMAIL PROTECTED]> wrote: > is there a way to find out the size of an object in Python? e.g., how could > i get the size of a list or a tuple? "Size" can mean a lot of things, len(my_list) len(my_tuple) Although I have the feeling you mean "how many bytes does this object take in memory" - and I believe the short answer is no. Brett -- http://mail.python.org/mailman/listinfo/python-list
getting the size of an object
is there a way to find out the size of an object in Python? e.g., how could i get the size of a list or a tuple? -- You're never too young to have a Vietnam flashback -- http://mail.python.org/mailman/listinfo/python-list
