Skip to main content

Behold! the power of python

I was writing code to do bootstrapping on a set of data. I wanted a test case where if I asked for one bootstrap I would be returned the original data. lambdas and function references saved me from inefficient code.

if bootstraps == 1:
srri = lambda low, high, size: range(size)
else:
srri = scipy.random.random_integers

for boot in range(bootstraps):   
for r in range(n1):
 for c in range(n0):
   sample_size = trial_result[r][c].size
   choices = srri(0, sample_size-1, sample_size)
   meas_grid[r,c] = pylab.array(trial_result[r][c][choices],dtype=float).mean()

model_grid[:,:,:,boot], params[:,boot] = \
           process_grid(s0, s1, meas_grid)


Instead of

srri = scipy.random.random_integers
if bootstraps == 1:
for r in range(n1):
for c in range(n0):
  meas_grid[r,c] = pylab.array(trial_result[r][c],dtype=float).mean()

model_grid[:,:,:,boot], params[:,boot] = \
           process_grid(s0, s1, meas_grid)
else:
for boot in range(bootstraps):
for r in range(n1):
  for c in range(n0):
    sample_size = trial_result[r][c].size
    choices = srri(0, sample_size-1, sample_size)
    meas_grid[r,c] = pylab.array(trial_result[r][c][choices],dtype=float).mean()

model_grid[:,:,:,boot], params[:,boot] = \
           process_grid(s0, s1, meas_grid)


OR
srri = scipy.random.random_integers
for boot in range(bootstraps):
if bootstraps == 1:
for r in range(n1):
  for c in range(n0):
    meas_grid[r,c] = pylab.array(trial_result[r][c],dtype=float).mean()

 model_grid[:,:,:,boot], params[:,boot] = \
           process_grid(s0, s1, meas_grid)
else:
for r in range(n1):
  for c in range(n0):
    sample_size = trial_result[r][c].size
    choices = srri(0, sample_size-1, sample_size)
    meas_grid[r,c] = pylab.array(trial_result[r][c][choices],dtype=float).mean()

model_grid[:,:,:,boot], params[:,boot] = \
           process_grid(s0, s1, meas_grid)
Labels:

Comments

Post a Comment

Popular posts from this blog

A note on Python's __exit__() and errors

Python's context managers are a very neat way of handling code that needs a teardown once you are done. Python objects have do have a destructor method ( __del__ ) called right before the last instance of the object is about to be destroyed. You can do a teardown there. However there is a lot of fine print to the __del__ method. A cleaner way of doing tear-downs is through Python's context manager , manifested as the with keyword. class CrushMe: def __init__(self): self.f = open('test.txt', 'w') def foo(self, a, b): self.f.write(str(a - b)) def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): self.f.close() return True with CrushMe() as c: c.foo(2, 3) One thing that is important, and that got me just now, is error handling. I made the mistake of ignoring all those 'junk' arguments ( exc_type, exc_val, exc_tb ). I just skimmed the docs and what popped out is that you need to return True or
Post a Comment
Read more

Using adminer on Mac OS X

adminer is a nice php based sqlite manager. I prefer the firefox plugin "sqlite manager" but it currently has a strange issue with FF5 that basically makes it unworkable, so I was looking for an alternative to tide me over. I really don't want apache running all the time on my computer and don't want people browsing to my computer, so what I needed to do was: Download the adminer php script into /Library/WebServer/Documents/ Change /etc/apache2/httpd.conf to allow running of php scripts (uncomment the line that begins: LoadModule php5_module Start the apache server: sudo apachectl -k start Operate the script by going to localhost Stop the server: sudo apachectl -k stop  
Post a Comment
Read more