How can I build a iterated function using the return value as the input parameter

Question

For some function f and variable a,

b_1 = f(a), 
b_2 = f(b_1), 
b_3 = f(b_2) 
...
b_n = f(b_n-1)

I would like to do n-times by iterated method. In a functional way, this is accomplished by a function composition.

f...(f(f((a)))

Something like `functools.reduce(lambda b, _: f(b), range(n), a)`… — deceze, Aug 20 '19 at 12:40
@deceze thanks. but how can I solve this problem with imperative loop without using the high-order function such as reduce? — jjjuab, Aug 20 '19 at 15:34

score 0 · Accepted Answer · answered Aug 20 '19 at 12:42

0

You can achive your result by recusion

you can refer below pesudo code

#define  f(a):
    # do computation

    # if terminating condition
        # then return the computed result
    #else
        # return f(computed result)

answered Aug 20 '19 at 12:42

rohit prakash

565
6
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This is a bad solution, as it will cause a stack overflow for a large enough `n`. – deceze Aug 20 '19 at 12:44
@deceze I think this will not cause stack overflow for large n because here tail recursion is used – rohit prakash Aug 20 '19 at 13:13
python also do tail call eliminination – rohit prakash Aug 20 '19 at 13:14
https://stackoverflow.com/questions/13591970/does-python-optimize-tail-recursion – deceze Aug 20 '19 at 13:19

How can I build a iterated function using the return value as the input parameter

1 Answers1