https://github.com/rougier/numpy-100
How to ignore all numpy warnings (not recommended)?
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defaults = np.seterr(all="ignore")
Z = np.ones(1) / 0
_ = np.seterr(**defaults)
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An equivalent way, with a context manager:
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with np.errstate(divide='ignore'):
Z = np.ones(1) / 0
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Is the following expressions true?
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np.sqrt(-1) == np.emath.sqrt(-1)
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How to get the dates of yesterday, today and tomorrow?
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yesterday = np.datetime64('today', 'D') - np.timedelta64(1, 'D')
today = np.datetime64('today', 'D')
tomorrow = np.datetime64('today', 'D') + np.timedelta64(1, 'D')
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How to get all the dates corresponding to the month of July 2016?
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Z = np.arange('2016-07', '2016-08', dtype='datetime64[D]')
print(Z)
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How to compute ((A+B)*(-A/2)) in place (without copy)?
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A = np.ones(3)*1
B = np.ones(3)*2
C = np.ones(3)*3
np.add(A,B,out=B)
np.divide(A,2,out=A)
np.negative(A,out=A)
np.multiply(A,B,out=A)
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Extract the integer part of a random array using 5 different methods
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Z = np.random.uniform(0,10,10)
print (Z - Z%1)
print (np.floor(Z))
print (np.ceil(Z)-1)
print (Z.astype(int))
print (np.trunc(Z))
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Create a 5x5 matrix with row values ranging from 0 to 4
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Z = np.zeros((5,5))
Z += np.arange(5)
print(Z)
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Consider a generator function that generates 10 integers and use it to build an array
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def ():
for x in range(10):
yield x
Z = np.fromiter(generate(),dtype=float,count=-1)
print(Z)
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Create a vector of size 10 with values ranging from 0 to 1, both excluded
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Z = np.linspace(0,1,11,endpoint=False)[1:]
print(Z)
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Create a random vector of size 10 and sort it
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Z = np.random.random(10)
Z.sort()
print(Z)
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