np numpy code example

Example 1: numpy

>>> import numpy as np
>>> a = np.array([2,3,4])
>>> a
array([2, 3, 4])
>>> a.dtype
dtype('int64')
>>> b = np.array([1.2, 3.5, 5.1])
>>> b.dtype
dtype('float64')

Example 2: numpy how to dropzero

X = np.random.randn(1e3, 5)
X[np.abs(X)< .1]= 0 # some zeros
X = np.ma.masked_equal(X,0)
plt.boxplot(X) #masked values are not plotted

#other functionalities of masked arrays
X.compressed() # get normal array with masked values removed
X.mask # get a boolean array of the mask
X.mean() # it automatically discards masked values

Example 3: numpy

t = True
f = False
print(type(t)) # Prints "<class 'bool'>"
print(t and f) # Logical AND; prints "False"
print(t or f)  # Logical OR; prints "True"
print(not t)   # Logical NOT; prints "False"
print(t != f)  # Logical XOR; prints "True"