Introduction to some functions of the numpy scientific computing library in python

Array details
asarray usage
data type object dtype
type dtype astype difference between
zeros usage
numpy
ndarray object numpy.place(arr, mask, vals)
NaN (not a number) , in mathematical representation, it represents an unrepresentable number, and here is generally There is another expression inf. The difference between inf and nan is that inf is a floating-point number that exceeds the range of floating-point representation (its essence is still a number, but it is infinite, so it cannot be represented by a floating-point number, such as 1/0). nan generally represents a non-floating point number (such as an irrational number).
nan in numpy or nan in pandas

mod in numpy