Python chain several functions into one-CodePudding

I have several string processing functions like:

def func1(s):
    return re.sub(r'\s', "", s)

def func2(s):
    return f"[{s}]"
...

I want to combine them into one pipeline function: my_pipeline(), so that I can use it as an argument, for example:

class Record:
    def __init__(self, s):
        self.name = s
    
    def apply_func(self, func):
        return func(self.name)

rec = Record(" hell o")
output = rec.apply_func(my_pipeline)
# output = "[hello]"

The goal is to use my_pipeline as an argument, otherwise I need to call these functions one by one.

Thank you.

CodePudding user response：

You can write a simple factory function or class to build a pipeline function:

>>> def pipeline(*functions):
...     def _pipeline(arg):
...         restult = arg
...         for func in functions:
...             restult = func(restult)
...         return restult
...     return _pipeline
...
>>> rec = Record(" hell o")
>>> rec.apply_func(pipeline(func1, func2))
'[hello]'

CodePudding user response：

You can just create a function which calls these functions:

def my_pipeline(s):
    return func1(func2(s))

CodePudding user response：

Using a list of functions (so you can assemble these elsewhere):

def func1(s):
    return re.sub(r'\s', "", s)

def func2(s):
    return f"[{s}]"

def func3(s):
    return s   'tada '

def callfuncs(s, pipeline):
    f0 = s
    pipeline.reverse()
    for f in pipeline:
        f0 = f(f0)        
    return f0

class Record:
    def __init__(self, s):
        self.name = s

    def apply_func(self, pipeline):
        return callfuncs(s.name, pipeline)
        
# calling order func1(func2(func3(s)))
my_pipeline = [func1, func2, func3]
rec = Record(" hell o")
output = rec.apply_func(my_pipeline)