1, map () passed in two parameters, function and iterable objects (Itreable), map () is to pass in the function of each element of the sequence in turn, the result is the return of a new iterable object (Iterable).
The map() code is as follows:
# Define the f function that returns x*x def f(x): return x*x # Call map() and act on each element in turn, based on the function and list passed in s=map(f,[1,2,3,4,5]) # Print the value of the returned iterator print(list(s)) # View type print(type(s))
Results:
[1, 4, 9, 16, 25]
<class 'map'>Process finished with exit code 0
Of course, you can also not use map(), the code is as follows:
# Define a list l=[1,2,3,4,5] #() is used to create a list, the result returns the square of the elements of list l in turn, return list s=[i*i for i in l] # Print list s print(s) # [] is used to create a generator that returns the squares of the elements of list l in order, returning generator s1=(i*i for i in l) # Print the values of the elements of generator as a list print(list(s1)) # View the type of s1 print(type(s1))
Results:
[1, 4, 9, 16, 25]
[1, 4, 9, 16, 25]
<class 'generator'>Process finished with exit code 0
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