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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Tabulation
In this tutorial, we will explore samplics' APIs for creating design-based tabulations. There are two main python classes for tabulation i.e. Tabulation() for one-way tables and CrossTabulation() for two-way tables.
Step1:  One-way tabulation
The birth dataset has four variables
Step2:  When requesting a table, the user can set parameter="count" which results in a tabulation with counts in the cells while parameter="proportion leads to cells with proportions. The expression Tabulation("count") instantiates the class Tabulation() which has a method tabulate() to produce the table.
Step3:  When remove_nan=False, the numpy and pandas special values NaNs, respectively np.nan and NaN, are treated as valid categories and added to the tables as shown below
Step4:  The data associated with the tabulation are stored in nested python dictionnaires. The higher level key is the variable name and the inner keys are the response categories. Each of the last four columns shown above are stored in separated dictionnaires. Two of those dictionnaires for the counts and standard errors shown below.
Step5:  Sometimes, the user may want to run multiple one-way tabules of several variables. In this case, the user can provide the data as a two-dimensional dataframe where each column represents one categorical variable. In this situation, each categorical variable is tabulated individually then combined into Python dictionnaires.
Step6:  Two of the associated Python dictionnaires are shown below. The structure of the inner dictionnaires remain the same but additional key-value pairs are added to represent the several categorical variables.
Step7:  In the example above, we used pandas series and dataframes with labelled variables. In some situations, the user may want to tabulate numpy arrays, lists or tuples without variable names atrribute from the data. For these situations, the varnames parameter provides a way to assign names for the categorical variables. Even when the variables have labels, users can leverage varnames to rename the categorical variables.
Step8:  If the user does not specify varnames, the tabulate() creates generic variables names var_1, var_2, etc.
Step9:  If the data was collected from a complex survey sample, the user may provide the sample design information to derive design-based statistics for the tabulation.
Step10:  Two-way tabulation (cross-tabulation)
Cross-tabulation of two categorical variables is achieved by using the class CrossTabulation(). As above, cross-tabulation is possible for counts and proportions using CrossTabulation(parameter="count") and CrossTabulation(parameter="proportion"), respectively. The Python script below creates a design-based cross-tabulation of race by diabetes status. The sample design information is optional; when not provided, a simple random sample (srs) is assumed.
Step11:  In addition to pandas dataframe, the categorical variables may be provided as an numpy array, list or tuple. In the examples below, the categorical variables are provided as a tuple vars=(rage, diabetes). In this case, race and diabetes are numpy arrays and do not have a name attribute. The parameter varnames allows the user to name the categorical variables. If varnames is not specified then var_1 and var_2 are used as variables names.
Step12:  Same as the above example with variables names specified by varnames=["Race", DiabetesStatus"]
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Python Code:
import numpy as np
import pandas as pd
from pprint import pprint
import samplics 
from samplics.datasets import Birth, Nhanes2
from samplics.categorical import Tabulation, CrossTabulation
Explanation: Tabulation
In this tutorial, we will explore samplics' APIs for creating design-based tabulations. There are two main python classes for tabulation i.e. Tabulation() for one-way tables and CrossTabulation() for two-way tables.
End of explanation
# Load Birth sample data
birth_cls = Birth()
birth_cls.load_data()
birth = birth_cls.data.astype({"region": str, "agecat":str, "birthcat": str})
region = birth["region"]
agecat = birth["agecat"]
birthcat = birth["birthcat"]
birth.head(15)
Explanation: One-way tabulation
The birth dataset has four variables: region, agecat, birthcat, and pop. The variables agecat and birthcat are categirical. By default, pandas read them as numerical, because they are coded with numerical values. We use dtype="string" or dtype="category" to ensure that pandas codes the variables as categorical responses.
End of explanation
birth_count = Tabulation(parameter="count")
birth_count.tabulate(birthcat, remove_nan=True)
print(birth_count)
Explanation: When requesting a table, the user can set parameter="count" which results in a tabulation with counts in the cells while parameter="proportion leads to cells with proportions. The expression Tabulation("count") instantiates the class Tabulation() which has a method tabulate() to produce the table.
End of explanation
birth_count = Tabulation(parameter="count")
birth_count.tabulate(birthcat, remove_nan=False)
print(birth_count)
Explanation: When remove_nan=False, the numpy and pandas special values NaNs, respectively np.nan and NaN, are treated as valid categories and added to the tables as shown below
End of explanation
print("\nThe designed-based estimated counts are:")
pprint(birth_count.point_est)
print("\nThe designed-based standard errors are:")
pprint(birth_count.stderror)
Explanation: The data associated with the tabulation are stored in nested python dictionnaires. The higher level key is the variable name and the inner keys are the response categories. Each of the last four columns shown above are stored in separated dictionnaires. Two of those dictionnaires for the counts and standard errors shown below.
End of explanation
birth_count2 = Tabulation(parameter="count")
birth_count2.tabulate(birth[["region", "agecat", "birthcat"]], remove_nan=True)
print(birth_count2)
Explanation: Sometimes, the user may want to run multiple one-way tabules of several variables. In this case, the user can provide the data as a two-dimensional dataframe where each column represents one categorical variable. In this situation, each categorical variable is tabulated individually then combined into Python dictionnaires.
End of explanation
print("\nThe designed-based estimated counts are:")
pprint(birth_count2.point_est)
print("\nThe designed-based standard errors are:")
pprint(birth_count2.stderror)
Explanation: Two of the associated Python dictionnaires are shown below. The structure of the inner dictionnaires remain the same but additional key-value pairs are added to represent the several categorical variables.
End of explanation
region_no_name = birth["region"].to_numpy()
agecat_no_name = birth["agecat"].to_numpy()
birthcat_no_name = birth["birthcat"].to_numpy()
birth_prop_new_name = Tabulation(parameter="proportion")
birth_prop_new_name.tabulate(
    vars=[region_no_name, agecat_no_name, birthcat_no_name], 
    varnames=["Region", "AgeGroup", "BirthType"], 
    remove_nan=True
)
print(birth_prop_new_name)
Explanation: In the example above, we used pandas series and dataframes with labelled variables. In some situations, the user may want to tabulate numpy arrays, lists or tuples without variable names atrribute from the data. For these situations, the varnames parameter provides a way to assign names for the categorical variables. Even when the variables have labels, users can leverage varnames to rename the categorical variables.
End of explanation
birth_prop_new_name2 = Tabulation(parameter="proportion")
birth_prop_new_name2.tabulate(
    vars=[region_no_name, agecat_no_name, birthcat_no_name], 
    remove_nan=True
)
print(birth_prop_new_name2)
Explanation: If the user does not specify varnames, the tabulate() creates generic variables names var_1, var_2, etc.
End of explanation
# Load Nhanes sample data
nhanes2_cls = Nhanes2()
nhanes2_cls.load_data()
nhanes2 = nhanes2_cls.data
stratum = nhanes2["stratid"]
psu = nhanes2["psuid"]
weight = nhanes2["finalwgt"]
diabetes_nhanes = Tabulation("proportion")
diabetes_nhanes.tabulate(
    vars=nhanes2[["race", "diabetes"]], samp_weight=weight, stratum=stratum, psu=psu, remove_nan=True
)
print(diabetes_nhanes)
Explanation: If the data was collected from a complex survey sample, the user may provide the sample design information to derive design-based statistics for the tabulation.
End of explanation
crosstab_nhanes = CrossTabulation("proportion")
crosstab_nhanes.tabulate(
    vars=nhanes2[["race", "diabetes"]], samp_weight=weight, stratum=stratum, psu=psu, remove_nan=True
)
print(crosstab_nhanes)
Explanation: Two-way tabulation (cross-tabulation)
Cross-tabulation of two categorical variables is achieved by using the class CrossTabulation(). As above, cross-tabulation is possible for counts and proportions using CrossTabulation(parameter="count") and CrossTabulation(parameter="proportion"), respectively. The Python script below creates a design-based cross-tabulation of race by diabetes status. The sample design information is optional; when not provided, a simple random sample (srs) is assumed.
End of explanation
race = nhanes2["race"].to_numpy()
diabetes = nhanes2["diabetes"].to_numpy()
crosstab_nhanes = CrossTabulation("proportion")
crosstab_nhanes.tabulate(
    vars=(race, diabetes), samp_weight=weight, stratum=stratum, psu=psu, remove_nan=True
)
print(crosstab_nhanes)
Explanation: In addition to pandas dataframe, the categorical variables may be provided as an numpy array, list or tuple. In the examples below, the categorical variables are provided as a tuple vars=(rage, diabetes). In this case, race and diabetes are numpy arrays and do not have a name attribute. The parameter varnames allows the user to name the categorical variables. If varnames is not specified then var_1 and var_2 are used as variables names.
End of explanation
crosstab_nhanes = CrossTabulation("proportion")
crosstab_nhanes.tabulate(
    vars=(race, diabetes), varnames=["Race", "DiabetesStatus"], samp_weight=weight, stratum=stratum, psu=psu, remove_nan=True
)
print(crosstab_nhanes)
Explanation: Same as the above example with variables names specified by varnames=["Race", DiabetesStatus"]
End of explanation
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