'''
Glue for returning descriptive statistics.
'''
import numpy as np
from scipy import stats
import os
from statsmodels.stats.descriptivestats import sign_test
#############################################
#
#============================================
# Univariate Descriptive Statistics
#============================================
#
[docs]def descstats(data, cols=None, axis=0):
'''
Prints descriptive statistics for one or multiple variables.
Parameters
----------
data: numpy array
`x` is the data
v: list, optional
A list of the column number or field names (for a recarray) of variables.
Default is all columns.
axis: 1 or 0
axis order of data. Default is 0 for column-ordered data.
Examples
--------
>>> descstats(data.exog,v=['x_1','x_2','x_3'])
'''
x = np.array(data) # or rather, the data we're interested in
if cols is None:
# if isinstance(x, np.recarray):
# cols = np.array(len(x.dtype.names))
if not isinstance(x, np.recarray) and x.ndim == 1:
x = x[:,None]
if x.shape[1] == 1:
desc = '''
---------------------------------------------
Univariate Descriptive Statistics
---------------------------------------------
Var. Name %(name)12s
----------
Obs. %(nobs)22i Range %(range)22s
Sum of Wts. %(sum)22s Coeff. of Variation %(coeffvar)22.4g
Mode %(mode)22.4g Skewness %(skewness)22.4g
Repeats %(nmode)22i Kurtosis %(kurtosis)22.4g
Mean %(mean)22.4g Uncorrected SS %(uss)22.4g
Median %(median)22.4g Corrected SS %(ss)22.4g
Variance %(variance)22.4g Sum Observations %(sobs)22.4g
Std. Dev. %(stddev)22.4g
''' % {'name': cols, 'sum': 'N/A', 'nobs': len(x), 'mode': \
stats.mode(x)[0][0], 'nmode': stats.mode(x)[1][0], \
'mean': x.mean(), 'median': np.median(x), 'range': \
'('+str(x.min())+', '+str(x.max())+')', 'variance': \
x.var(), 'stddev': x.std(), 'coeffvar': \
stats.variation(x), 'skewness': stats.skew(x), \
'kurtosis': stats.kurtosis(x), 'uss': np.sum(x**2, axis=0),\
'ss': np.sum((x-x.mean())**2, axis=0), 'sobs': np.sum(x)}
desc+= '''
Percentiles
-------------
1 %% %12.4g
5 %% %12.4g
10 %% %12.4g
25 %% %12.4g
50 %% %12.4g
75 %% %12.4g
90 %% %12.4g
95 %% %12.4g
99 %% %12.4g
''' % tuple([stats.scoreatpercentile(x,per) for per in (1,5,10,25,
50,75,90,95,99)])
t,p_t=stats.ttest_1samp(x,0)
M,p_M=sign_test(x)
S,p_S=stats.wilcoxon(np.squeeze(x))
desc+= '''
Tests of Location (H0: Mu0=0)
-----------------------------
Test Statistic Two-tailed probability
-----------------+-----------------------------------------
Student's t | t %7.5f Pr > |t| <%.4f
Sign | M %8.2f Pr >= |M| <%.4f
Signed Rank | S %8.2f Pr >= |S| <%.4f
''' % (t,p_t,M,p_M,S,p_S)
# Should this be part of a 'descstats'
# in any event these should be split up, so that they can be called
# individually and only returned together if someone calls summary
# or something of the sort
elif x.shape[1] > 1:
desc ='''
Var. Name | Obs. Mean Std. Dev. Range
------------+--------------------------------------------------------'''+\
os.linesep
# for recarrays with columns passed as names
# if isinstance(cols[0],str):
# for var in cols:
# desc += "%(name)15s %(obs)9i %(mean)12.4g %(stddev)12.4g \
#%(range)20s" % {'name': var, 'obs': len(x[var]), 'mean': x[var].mean(),
# 'stddev': x[var].std(), 'range': '('+str(x[var].min())+', '\
# +str(x[var].max())+')'+os.linesep}
# else:
for var in range(x.shape[1]):
xv = x[:, var]
kwargs = {
'name': var,
'obs': len(xv),
'mean': xv.mean(),
'stddev': xv.std(),
'range': '('+str(xv.min())+', '+str(xv.max())+')'+os.linesep
}
desc += ("%(name)15s %(obs)9i %(mean)12.4g %(stddev)12.4g "
"%(range)20s" % kwargs)
else:
raise ValueError("data not understood")
return desc
#if __name__=='__main__':
# test descstats
# import os
# loc='http://eagle1.american.edu/~js2796a/data/handguns_data.csv'
# relpath=(load_dataset(loc))
# dta=np.recfromcsv(relpath)
# descstats(dta,['stpop'])
# raw_input('Hit enter for multivariate test')
# descstats(dta,['stpop','avginc','vio'])
# with plain arrays
# import string2dummy as s2d
# dts=s2d.string2dummy(dta)
# ndts=np.vstack(dts[col] for col in dts.dtype.names)
# observations in columns and data in rows
# is easier for the call to stats
# what to make of
# ndts=np.column_stack(dts[col] for col in dts.dtype.names)
# ntda=ntds.swapaxis(1,0)
# ntda is ntds returns false?
# or now we just have detailed information about the different strings
# would this approach ever be inappropriate for a string typed variable
# other than dates?
# descstats(ndts, [1])
# raw_input("Enter to try second part")
# descstats(ndts, [1,20,3])
if __name__ == '__main__':
import statsmodels.api as sm
data = sm.datasets.longley.load(as_pandas=False)
data.exog = sm.add_constant(data.exog, prepend=False)
sum1 = descstats(data.exog)
sum1a = descstats(data.exog[:,:1])
# loc='http://eagle1.american.edu/~js2796a/data/handguns_data.csv'
# dta=np.recfromcsv(loc)
# summary2 = descstats(dta,['stpop'])
# summary3 = descstats(dta,['stpop','avginc','vio'])
#TODO: needs a by argument
# summary4 = descstats(dta) this fails
# this is a bug
# p = dta[['stpop']]
# p.view(dtype = np.float, type = np.ndarray)
# this works
# p.view(dtype = np.int, type = np.ndarray)
### This is *really* slow ###
if os.path.isfile('./Econ724_PS_I_Data.csv'):
data2 = np.recfromcsv('./Econ724_PS_I_Data.csv')
sum2 = descstats(data2.ahe)
sum3 = descstats(np.column_stack((data2.ahe,data2.yrseduc)))
sum4 = descstats(np.column_stack(([data2[_] for \
_ in data2.dtype.names])))
