Running a script once, reserves input parameters and outputs in Python's namespace, allowing you to check the state of these in the Interactive Window, IW, at any time. Often I save the results of the Interactive Window to document a particular case or change in state of one of the inputs. I was getting bored writing multiple print statements to try to remember what the inputs and outputs were. Moreover, I had documented all this in the script in the header.
I decided to combine the best of both worlds: 1) reduce the number of print statements; 2) retrieve the header information so I could check namespace and outputs in the IW which I could then save and/or print.
The following are the results of a demo scripts output which includes the input namespace and their meaning and the results for a run. The actual script is not relevant but I have included it anyways as an attachment. The example here is the result from PythonWin's IW. I did take a huge chunk out of the outputs to facilitate reading.
----------------------------------------------------------------------
:Script: matrix_covariance_demo.py
:Author: Dan.Patterson@carleton.ca
:Modified: 2016-10-25
:
:Notes:
: Namespace....
: x, y x,y values
: xy_s X,Y values zipped together forming a column list
: x_m, y_m means of X and Y
: x_t, x_t X and Y converted to arrays and translated to form row arrays
: s_x, s_y sample std. deviations
: v_x, v_y sample variances
: cov_m numpy covariance matrix, sample treatement, see docs re: ddof
: Exy sum of the X_t,Y_t products
: cv_alt alternate method of calculating "cov_m" in terms of var. etc
:
: Useage....
: Create a list of key values in execuation order, print using locals()
: Syntax follows...
: names = ["x","x","xy_s","x_m","y_m","xy_t","x_t","y_t",
: "s_x","s_y","v_x","v_y","cov_m","Exy","n","cv_alt"]
: for name in names:
: print("{!s:<8}:\n {!s: <60}".format(name, locals()[name]))
:
:References
: http://en.wikipedia.org/wiki/Pearson_product-moment_
: correlation_coefficient
: http://stackoverflow.com/questions/932818/retrieving-a-variables-
: name-in-python-at-runtime
:
)
Results listed in order of execution:
x .... [1.0, 2.0, 3.0, 5.0, 8.0]
y .... [0.11, 0.12, 0.13, 0.15, 0.18]
xy_s .... [(1.0, 0.11), (2.0, 0.12), (3.0, 0.13), (5.0, 0.15), (8.0, 0.18)]
x_m .... 3.8
y_m .... 0.138
x_t .... [-2.800 -1.800 -0.800 1.200 4.200]
y_t .... [-0.028 -0.018 -0.008 0.012 0.042]
s_x .... 2.7748873851
s_y .... 0.027748873851
v_x .... 7.7
v_y .... 0.00077
cov_m .... [[ 7.700 0.077], [ 0.077 0.001]]
Exy .... 0.308
n .... 4
cv_alt.... [[ 7.700 0.077], [ 0.077 0.001]]
Now the code.... I have left out the scripts doc since I always like to keep a copy in the output so I don't forget what I used to produce it. The only real important parts are the list of names in the main part of the script and the lines in the __main__ section to process the locals() variable yes.
.... SNIP ....
import sys
import numpy as np
from numpy.linalg import linalg as nla
from textwrap import dedent
ft = {"bool": lambda x: repr(x.astype("int32")),
"float": "{: 0.3f}".format}
np.set_printoptions(edgeitems=10, linewidth=80, precision=2,
suppress=True, threshold=100,
formatter=ft)
script = sys.argv[0]
x = [1.0, 2.0, 3.0, 5.0, 8.0]
y = [0.11, 0.12, 0.13, 0.15, 0.18]
xy_s = list(zip(x, y))
x_m, y_m = np.mean(xy_s, axis=0)
xy_t = np.array(xy_s) - [x_m, y_m]
x_t, y_t = xy_t.T
s_x, s_y = np.std(xy_t, axis=0, ddof=1)
v_x, v_y = np.var(xy_t, axis=0, ddof=1)
cov_m = np.cov(x_t, y_t, ddof=1)
Exy = np.sum(np.product(xy_t, axis=1))
n = len(x_t) - 1
cv_alt = np.array([[v_x, Exy/n], [Exy/n, v_y]])
names = ["x", "y", "xy_s",
"x_m", "y_m", "x_t", "y_t",
"s_x", "s_y", "v_x", "v_y",
"cov_m", "Exy", "n", "cv_alt"]
if __name__ == "__main__":
print("\n{}\n{})".format("-"*70, __doc__))
print("\nResults listed in order of execution:")
for name in names:
args = [name, str(locals()[name]).replace("\n", ",")]
print("{!s:<6}.... {!s:}".format(*args))
Hope you find something useful in this. Send comments via email.
