looping to define a sequence of functions?

[r.e.s.]

Suppose we want to define ten functions such that the
nth function of x simply returns x**n. Is there a way
to avoid explicitly writing ten function def's? (They
have to be ten distinct functions, not just a single
one like def f(n,x): return x**n.)

E.g., the following doesn't work:

f = {}
for n in range(10):
def f[n](x):
return x**n

Thanks.
--
r.e.s.

[Rainer Deyke]

r.e.s. wrote:

Suppose we want to define ten functions such that the
nth function of x simply returns x**n. Is there a way
to avoid explicitly writing ten function def's? (They
have to be ten distinct functions, not just a single
one like def f(n,x): return x**n.)

functions = [lambda x, n=n: x**n for n in range(10)]

-or-

class X(object):
def __init__(self, n):
self.n = n
def __call__(self, x):
return x ** self.n
functions = [X(n) for n in range(10)]

-or-

functions = []
for n in range(10):
def f(x, n=n):
return x**n
functions.append(f)

-or-

def create_function(n):
def f(x):
return x**n
return f
functions = [create_function(n) for n in range(10)]
--
Rainer Deyke - ra*****@eldwood.com - http://eldwood.com

[r.e.s.]

"Rainer Deyke" <ra*****@eldwood.com> wrote ...

r.e.s. wrote:

Suppose we want to define ten functions such that the
nth function of x simply returns x**n. Is there a way
to avoid explicitly writing ten function def's? (They
have to be ten distinct functions, not just a single
one like def f(n,x): return x**n.)

functions = [lambda x, n=n: x**n for n in range(10)]

-or-

class X(object):
def __init__(self, n):
self.n = n
def __call__(self, x):
return x ** self.n
functions = [X(n) for n in range(10)]

-or-

functions = []
for n in range(10):
def f(x, n=n):
return x**n
functions.append(f)

-or-

def create_function(n):
def f(x):
return x**n
return f
functions = [create_function(n) for n in range(10)]
--
Rainer Deyke - ra*****@eldwood.com - http://eldwood.com

It's going to take me a bit to digest these, and
it looks like I'm sure to learn from them, so I
want to say 'thank you' now for the quick reply.

[Peter Abel]

"r.e.s." <r.*@ZZmindspring.com> wrote in message news:<T9*******************@newsread2.news.pas.ear thlink.net>...

Suppose we want to define ten functions such that the
nth function of x simply returns x**n. Is there a way
to avoid explicitly writing ten function def's? (They
have to be ten distinct functions, not just a single
one like def f(n,x): return x**n.)

E.g., the following doesn't work:

f = {}
for n in range(10):
def f[n](x):
return x**n

Thanks.

# A parametric factory-function that returns
# a function depending on the parameter n
def factory_function(n): .... def fn(x):
.... return x**n
.... return fn
.... # A list of ten different functions
func_list=map(factory_function,range(10))
# And an example of the result with x=2
for i,func in zip(range(len(func_list)),func_list): .... print '%2d: %d' % (i,func(2))
....
0: 1
1: 2
2: 4
3: 8
4: 16
5: 32
6: 64
7: 128
8: 256
9: 512

Regards
Peter