# numpy.zeros: --> ndarray
# numpy.ones: --> ndarray
import numpy as np
print np.zeros(3)
print np.zeros((3, 4))
print np.ones(4)

import numpy as np
# standard normal
print np.random.randn(5, 2)
# uniform 0-1
print np.random.rand(2, 4)

import numpy as np
# normal
print np.random.normal(4.2, 8, 10)
# poisson
print np.random.poisson(3.2, (4, 2))

# Series.value_counts: --> Series
import pandas as pd
s = pd.Series([1, 2, 2, 1, 2, 4, 1, 3])
t = pd.Series(["a", "b", "a", "a", "c", "5", 5])
print s.value_counts()
print t.value_counts()
print type(s)