1.3. Built-ins¶
1.3.1. Pi number¶
import numpy as np
np.pi
# 3.1415926535897931
1.3.2. Euler number¶
import numpy as np
np.e
# 2.7182818284590451
1.3.3. Infinite¶
import numpy as np
np.inf
# inf
np.Infinity
# inf
np.Inf
# inf
np.PINF
# inf
np.NINF
# -inf
-np.inf
# -inf
-np.Inf
# -inf
-np.Infinity
# -inf
import numpy as np
float('Inf')
# inf
float('Infinity')
# inf
float('inf')
# inf
np.inf == float('inf')
# True
np.inf is float('inf')
# False
import numpy as np
np.inf + 1 # inf
np.inf + np.inf # inf
np.inf - np.inf # nan
np.inf - np.nan # nan
np.inf * np.inf # inf
np.inf / np.inf # nan
0 / np.inf # 0.0
np.inf / 0 # ZeroDivisionError: float division by zero
import numpy as np
a = np.array([1, 2, np.inf])
# array([ 1., 2., inf])
np.isfinite(a)
# array([ True, True, False])
np.isinf(a)
# array([False, False, True])
import numpy as np
a = np.array([1, 2, np.inf])
# array([ 1., 2., inf])
np.isnan(a)
# array([False, False, False])
1.3.4. Not-a-Number¶
Special
float
valuePropagates in calculations
import numpy as np
np.NaN
# nan
np.NAN
# nan
np.nan
# nan
import numpy as np
float('nan')
# nan
np.nan is float('nan')
# False
np.nan == float('nan')
# False
np.nan is None
# False
np.nan == None
# False
import numpy as np
bool(None)
# False
bool(np.nan)
# True
import numpy as np
np.nan + 1 # nan
np.nan + np.nan # nan
np.nan - np.nan # nan
np.nan - np.inf # nan
np.nan / np.nan # nan
0 / np.nan # nan
np.nan / 0 # ZeroDivisionError: float division by zero
import numpy as np
a = np.array([1, 2, np.nan])
# array([ 1., 2., nan])
np.isnan(a)
# array([False, False, True])
import numpy as np
a = np.array([1, 2, np.nan])
# array([ 1., 2., nan])
np.isfinite(a)
# array([ True, True, False])
np.isinf(a)
# array([False, False, False])
1.3.5. Assignments¶
Todo
Create assignments