How to make python faster?

Python and other scripting languages ​​are often abandoned because they are inefficient compared to compiled languages ​​like C. For example, the following example of Fibonacci numbers:

In C language:

int fib(int n){
   if (n < 2)
     return n;
   else
     return fib(n - 1) + fib(n - 2);
}
int main() {
    fib(40);
    return 0;

In Python:

def fib(n):
  if n < 2:
     return n
  else:
     return fib(n - 1) + fib(n - 2)
fib(40)

Here are their respective execution times:

$ time ./fib
3.099s
  
$ time python fib.py
16.655s

As expected, the C language execution in this example The efficiency is 5 times faster than Python.

In the case of web scraping, execution speed is not very important because the bottleneck is I/O - downloading the web page. But I also want to use Python in other environments, so let's take a look at how to improve the execution speed of python.

First we install a python module: psyco. The installation is very simple. You only need to execute the following command:

sudo apt-get install python-psyco

Or if you are on centos, execute:

sudo yum install python-psyco

Then let’s verify it:

#引入psyco模块，author: www.pythontab.com
import psyco
psyco.full()
def fib(n):
  if n < 2:
     return n
  else:
     return fib(n - 1) + fib(n - 2)
fib(40)

Haha , witness the miraculous moment! !

$ time python fib.py
3.190s

It only took 3 seconds. After using the psyco module, python runs as fast as C!

Now I add the following code to almost most of my python codes to enjoy the speed improvement brought by psyco

try:
    import psyco
    psyco.full()
except ImportError:
    pass # psyco not installed so continue as usual