I'm trying to do Dirichlet Regression using Python. Unfortunately I cannot find a Python package that does the job. So I tried to call R library DirichletReg using rpy2. However, it is not very intuitive to me how to call a regression function such as DirichReg(Y ~ X1 + X2 + X3, data=predictorData) where Y = DR_data(compositionalData). I saw an example of calling linear regression function lm in the documentation of rpy2. But my case is slightly different as Y is not a column name in the table but an R object DR_data.
I'm wondering what the proper way is to do this, or whether there is a Python package for Dirichlet Regression.
You can send objects into the "Formula" environment from python. This example is from the rpy2 docs:
import array
from rpy2.robjects import IntVector, Formula
from rpy2.robjects.packages import importr
stats = importr('stats')
x = IntVector(range(1, 11))
y = x.ro + stats.rnorm(10, sd=0.2)
fmla = Formula('y ~ x')
env = fmla.environment
env['x'] = x
env['y'] = y
fit = stats.lm(fmla)
You can also create named variables in the R environment (outside the Formula). See here. Worst case scenario, you move some your python data into R through rpy2, then issue the commands directly in R through the rpy2 bridge as described here.
Related
I'd like to ask some questions about running lmer (Linear Mixed Effects Regression) models in Python.
Here are the two lines(or formulas) that I had run in the lme4 package(in R). Is there any way I could fit the models as below in Python?
TEST1 <- score ~ p1 + p2 + p3 + (1|v1) + (1|v2), data = df, control = lmerControl(boundary.tol = 1e-4, calc.derivs = FALSE))
TEST2 <- score ~ (1|v1) + (1|v2), data = df, control = lmerControl(boundary.tol = 1e-4, calc.derivs = FALSE))
If you aren't required to actually run the model in Python, you could call and run the LMER models in R directly from your Python environment.
You could do this through Rpy2 & rmagic or through Pymer4. Both options allow you to use the lme4 package in R with the option to call them from a Python environment like jupyter notebooks.
I wrote a tutorial on how you could do this with examples that is available here: https://towardsdatascience.com/how-to-run-linear-mixed-effects-models-in-python-jupyter-notebooks-4f8079c4b589
As EJJ noted, there are implementations of LMER in Python such as in statsmodels and Tensorflow but they appear less intuitive to use than the above method.
When calling a function in the survival package in R from within python with the rpy2 interface I get the following error:
RRuntimeError: Error in formula[[2]] : subscript out of bounds
Any pointer to solve the issue please?
Thanks
Code:
import pandas as pd
import rpy2.robjects.packages as rpackages
from rpy2.robjects.vectors import StrVector
from rpy2.robjects.packages import importr
import rpy2.robjects as ro
R = ro.r
from rpy2.robjects import pandas2ri
pandas2ri.activate()
## install the survival package
utils = rpackages.importr('utils')
utils.chooseCRANmirror(ind=1) # select the first mirror in the list
utils.install_packages(StrVector('survival'))
#Load the library and example data set
survival=importr('survival')
infert = R('infert')
## Linear model works fine
reslm=R.lm('case~spontaneous+induced',data=infert)
#Run the example clogit function, which fails
rescl=R.clogit('case~spontaneous+induced+strata(stratum)',data=infert)
After trying around, I found out, there is a difference, whether you offer the R instance of rpy2 the full R-code string to execute, or not.
Thus, you can make your function run, by giving as much as possible as R code:
#Run the example clogit function, which fails
rescl=R.clogit('case~spontaneous+induced+strata(stratum)',data=infert)
#But give the R code to be executed as one complete string - this works:
rescl=R('clogit(case ~ spontaneous + induced + strata(stratum), data = infert)')
If you capture the return value to a variable within R, you can inspect the data and get out the critical information of the model
by the usual functions in R.
E.g.
R('rescl.in.R <- clogit(case ~ spontaneous + induced + strata(stratum), data = infert)')
R('str(rescl.in.R)')
# or:
R('coef(rescl.in.R)')
## array([1.98587552, 1.40901163])
R('names(rescl.in.R)')
## array(['coefficients', 'var', 'loglik', 'score', 'iter',
## 'linear.predictors', 'residuals', 'means', 'method', 'n', 'nevent',
## 'terms', 'assign', 'wald.test', 'y', 'formula', 'xlevels', 'call',
## 'userCall'], dtype='<U17')
It helps a lot - at least in this first phase of using rpy2 (for me, too), to have your r instance open and trying the code in parallel which you do, since the output in R is far more readable and you know and see what you are doing and what you could address.
In Python, the output is stripped off of important informations (like the name etc) - and in addition, it is not pretty-printed.
This fails when including the strata() function within the formula because it's not evaluated in the right environment. In R, formulas are special language constructs and so they need to be treated separately by rpy2.
So, for your example, this would look like:
rescl = R.clogit(ro.Formula('case ~ spontaneous + induced + strata(stratum)'),
data = infert)
See the documentation for rpy2.robjects.Formula for more details. That documentation also discusses the pros & cons of this approach vs that provided by #Gwang-jin-kim
I am trying to define a splunk dashboard equivalent to this code in python
from scipy import stats
stats.beta.cdf(x, T, F) - stats.beta.cdf(y, T, F)
Where x and y are splunk expressions (defined with splunk's eval).
I saw a lot of complex stuff (classifiers, anomaly detection, etc...) when looking at the splunk docs, but I couldn't find any reference to known distribution functions such as Beta and Gamma.
Could someone refer me to any statistics package for splunk ?
I discovered the | script directive in splunk.
Now, This is the python code I wrote, and it runs directly from splunk
from scipy import stats
import splunk.Intersplunk
src_cols = ["s1","s2"]
new_cols = ["n1"]
print (",".join(src_cols+new_cols))
for row in splunk.Intersplunk.readResults():
output = map(lambda c: row[c], src_cols)
output += [stats.beta.cdf(row["s1"],0, 1) - row["s2"],0, 1)]
print (",".join(output))
I'm learning how to use rpy2, and I would like to create formatted regression output using the stargazer package. My best guess of how to do this is the following code:
import pandas as pd
import rpy2.robjects as robjects
from rpy2.robjects.packages import importr
stargazer = importr('stargazer')
from rpy2.robjects import pandas2ri
pandas2ri.activate()
r = robjects.r
df = pd.DataFrame({'x': [1,2,3,4,5],
'y': [2,1,3,5,4]})
fit = r.lm('y~x', data=df)
print fit
print r.stargazer(fit)
However, when I run it, the I get the following output:
Coefficients:
(Intercept) x
0.6 0.8
[1] "\n"
[2] "% Error: Unrecognized object type.\n"
So the fit is being generated, and prints fine. But stargazer doesn't seem to recognize the fit object as something it can parse.
Any suggestions? Am I calling stargazer incorrectly in this context?
I should mention that I am running this in Python 2.7.5 on a windows 10 machine, with R 3.3.2, and rpy2 version 2.7.8 from the unofficial windows binary. So it could just be a problem with the windows build, but it seems odd that everything except stargazer would work.
I am not familiar with the R package stargazer but from a quick look at the documentation this seems to be the correct usage.
Before anything, you may want to check whether the issue is with execution or with printing. At which one of the two lines is this failing ?
p = r.stargazer(fit)
print(p)
If the failure is with the execution, you may want to move more code to R and see if you reach a point where you get it to work. If not, this is likely an issue with the R code and/or stargazer. If you get it to work the issue is on the rpy2/conversion side.
rcode = """
df <- data.frame(x = c(1,2,3,4,5),
y = c(2,1,3,5,4))
fit <- lm('y~x', data=df)
p <- stargazer(fit)
"""
# parse and evaluate the R code
r(rcode)
# intermediate objects can be retrieved from the `globalenv` to
# investigate where they differ from the ones obtained earlier.
# For example:
print(robjects.globalenv["p"])
Now that we showed that it is likely an issue on the stargazer side, we can make the use of arbitrary data frames a matter of binding it to a symbol in R's globalenv:
robjects.globalenv["df"] = df
rcode = """
fit <- lm('y~x', data=df)
p <- stargazer(fit)
"""
# parse and evaluate the R code
r(rcode)
print(robjects.globalenv["p"])
I want to calculate logistic regression parameters using R's glm package. I'm working with python and using rpy2 for that.
For some reason, when I'm running the glm function using R I get much faster results than by using rpy2. Do you know why the calculations using rpy2 is much slower?
I'm using R - V2.13.1 and rpy2 - V2.0.8
Here is the code I'm using:
import numpy
from rpy2 import robjects as ro
import rpy2.rlike.container as rlc
def train(self, x_values, y_values, weights):
x_float_vector = [ro.FloatVector(x) for x in numpy.array(x_values).transpose()]
y_float_vector = ro.FloatVector(y_values)
weights_float_vector = ro.FloatVector(weights)
names = ['v' + str(i) for i in xrange(len(x_float_vector))]
d = rlc.TaggedList(x_float_vector + [y_float_vector], names + ['y'])
data = ro.RDataFrame(d)
formula = 'y ~ '
for x in names:
formula += x + '+'
formula = formula[:-1]
fit_res = ro.r.glm(formula=ro.r(formula), data=data, weights=weights_float_vector, family=ro.r('binomial(link="logit")'))
Without the full R code you are benchmarking against, it is difficult to precisely point out where the problem might be.
You might want to run this through a Python profiler to see where the bottleneck(s) is (are).
Finally, the current release for rpy2 is 2.2.6. Beside API changes, it is running faster and has (presumably) less bugs than 2.0.8.
Edit: From your comments I am now suspecting that you are calling your function
in a loop, and a large fraction of the time is spent building R vectors (that might only have to be built once).