Get total physical memory in Python

your best bet for a cross-platform solution is to use the psutil package (available on PyPI).

import psutil
    
psutil.virtual_memory().total  # total physical memory in Bytes

Documentation for virtual_memory is here.

Using os.sysconf on Linux:

import os
mem_bytes = os.sysconf('SC_PAGE_SIZE') * os.sysconf('SC_PHYS_PAGES')  # e.g. 4015976448
mem_gib = mem_bytes/(1024.**3)  # e.g. 3.74

Note:

• SC_PAGE_SIZE is often 4096.
• SC_PAGESIZE and SC_PAGE_SIZE are equal.
• For more info, see man sysconf.
• For MacOS, as per user reports, this works with Python 3.7 but not with Python 3.8.

Using /proc/meminfo on Linux:

meminfo = dict((i.split()[0].rstrip(':'),int(i.split()[1])) for i in open('/proc/meminfo').readlines())
mem_kib = meminfo['MemTotal']  # e.g. 3921852

Regular expressions work well for this sort of thing, and might help with any minor differences across distributions.

import re
with open('/proc/meminfo') as f:
    meminfo = f.read()
matched = re.search(r'^MemTotal:\s+(\d+)', meminfo)
if matched: 
    mem_total_kB = int(matched.groups()[0])