Python line_profiler code example

Question

I am trying to figure out how I can run Python's line_profiler to get the line by line execution times in the format given in the answer to this question.

I installed the module and am calling its LineProfiler object as below but the output I get is just a single time and not a line by line summary.

Any ideas? Furthermore, how can I get the time for the numbers = [random.randint(1,100) for i in range(1000)] line that is outside any function?

from line_profiler import LineProfiler import random  def do_stuff(numbers):      s = sum(numbers)     l = [numbers[i]/43 for i in range(len(numbers))]     m = ['hello'+str(numbers[i]) for i in range(len(numbers))]  numbers = [random.randint(1,100) for i in range(1000)] profile = LineProfiler(do_stuff(numbers)) profile.print_stats() [] Timer unit: 3.20721e-07 s 

Answer 1

The line_profiler test cases (found on GitHub) have an example of how to generate profile data from within a Python script. You have to wrap the function that you want to profile and then call the wrapper passing any desired function arguments.

from line_profiler import LineProfiler import random  def do_stuff(numbers):     s = sum(numbers)     l = [numbers[i]/43 for i in range(len(numbers))]     m = ['hello'+str(numbers[i]) for i in range(len(numbers))]  numbers = [random.randint(1,100) for i in range(1000)] lp = LineProfiler() lp_wrapper = lp(do_stuff) lp_wrapper(numbers) lp.print_stats() 

Output:

Timer unit: 1e-06 s  Total time: 0.000649 s File: <ipython-input-2-2e060b054fea> Function: do_stuff at line 4  Line #      Hits         Time  Per Hit   % Time  Line Contents ==============================================================      4                                           def do_stuff(numbers):      5         1           10     10.0      1.5      s = sum(numbers)      6         1          186    186.0     28.7      l = [numbers[i]/43 for i in range(len(numbers))]      7         1          453    453.0     69.8      m = ['hello'+str(numbers[i]) for i in range(len(numbers))] 

Adding Additional Functions to Profile

Also, you can add additional functions to be profiled as well. For example, if you had a second called function and you only wrap the calling function, you'll only see the profile results from the calling function.

from line_profiler import LineProfiler import random  def do_other_stuff(numbers):     s = sum(numbers)  def do_stuff(numbers):     do_other_stuff(numbers)     l = [numbers[i]/43 for i in range(len(numbers))]     m = ['hello'+str(numbers[i]) for i in range(len(numbers))]  numbers = [random.randint(1,100) for i in range(1000)] lp = LineProfiler() lp_wrapper = lp(do_stuff) lp_wrapper(numbers) lp.print_stats() 

The above would only produce the following profile output for the calling function:

Timer unit: 1e-06 s  Total time: 0.000773 s File: <ipython-input-3-ec0394d0a501> Function: do_stuff at line 7  Line #      Hits         Time  Per Hit   % Time  Line Contents ==============================================================      7                                           def do_stuff(numbers):      8         1           11     11.0      1.4      do_other_stuff(numbers)      9         1          236    236.0     30.5      l = [numbers[i]/43 for i in range(len(numbers))]     10         1          526    526.0     68.0      m = ['hello'+str(numbers[i]) for i in range(len(numbers))] 

In this case, you can add the additional called function to profile like this:

from line_profiler import LineProfiler import random  def do_other_stuff(numbers):     s = sum(numbers)  def do_stuff(numbers):     do_other_stuff(numbers)     l = [numbers[i]/43 for i in range(len(numbers))]     m = ['hello'+str(numbers[i]) for i in range(len(numbers))]  numbers = [random.randint(1,100) for i in range(1000)] lp = LineProfiler() lp.add_function(do_other_stuff)   # add additional function to profile lp_wrapper = lp(do_stuff) lp_wrapper(numbers) lp.print_stats() 

Output:

Timer unit: 1e-06 s  Total time: 9e-06 s File: <ipython-input-4-dae73707787c> Function: do_other_stuff at line 4  Line #      Hits         Time  Per Hit   % Time  Line Contents ==============================================================      4                                           def do_other_stuff(numbers):      5         1            9      9.0    100.0      s = sum(numbers)  Total time: 0.000694 s File: <ipython-input-4-dae73707787c> Function: do_stuff at line 7  Line #      Hits         Time  Per Hit   % Time  Line Contents ==============================================================      7                                           def do_stuff(numbers):      8         1           12     12.0      1.7      do_other_stuff(numbers)      9         1          208    208.0     30.0      l = [numbers[i]/43 for i in range(len(numbers))]     10         1          474    474.0     68.3      m = ['hello'+str(numbers[i]) for i in range(len(numbers))] 

NOTE: Adding functions to profile in this way does not require changes to the profiled code (i.e., no need to add @profile decorators).