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Javascript-like array-method chaining in Python?


Javascript-like array-method chaining in Python?

By : Amol Narkhede
Date : October 22 2020, 08:10 AM
hope this fix your issue I'm coming into python from a javascript background. In JS we can do array-method chaining, and it's awesome (especially with arrow functions): , In Python, you'd do:
code :
from operator import attrgetter
map(lambda x: x.name, 
    sorted(filter(lambda x: x.count > 10, someArray), 
           key=attrgetter("count"))
>>> from toolz.curried import pipe, map, filter, get
>>> pipe(accounts, filter(lambda acc: acc[2] > 150),
...                map(get([1, 2])),
...                list)
from functional import seq

seq(1, 2, 3, 4)\
    .map(lambda x: x * 2)\
    .filter(lambda x: x > 4)\
    .reduce(lambda x, y: x + y)
# 14


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Method chaining in javascript

Method chaining in javascript


By : Jonas Müller
Date : March 29 2020, 07:55 AM
it fixes the issue This working code is using Sproutcore: , Sproutcore is extending the function prototype.
code :
Function.prototype.property = function() { /* code here */ };
SC.mixin(Function.prototype, 
//...snip...

property: function() {
    this.dependentKeys = SC.$A(arguments) ;
    var guid = SC.guidFor(this) ;
    this.cacheKey = "__cache__" + guid ;
    this.lastSetValueKey = "__lastValue__" + guid ;
    this.isProperty = YES ;
    return this ;
  },
//snip
);
javascript method chaining, add methods from an array

javascript method chaining, add methods from an array


By : Lev Zak
Date : March 29 2020, 07:55 AM
this will help You can break the chain up into steps that you can conditionally perform based on the contents of transaction:
code :
var q = transaction.model.find(transaction.query);
if (offset) {
  q = q.skip(offset);
}
if (limit) {
  q = q.limit(limit);
}
if (transaction.populate) {
  transaction.populate.forEach(function(pop) {
     q = q.populate(pop.field, pop.select);
  });
}
q.exec(function(err, collection_obj){...});
Javascript Method Chaining: Correct method chain toFixed() and parseFloat() to return a number, not a string?

Javascript Method Chaining: Correct method chain toFixed() and parseFloat() to return a number, not a string?


By : Roberto Garcia
Date : March 29 2020, 07:55 AM
Hope this helps toFixed is a method of Number and returns a string. window.parseFloat is a global function and not a method of String, but if you really must, then you can make it a String method, otherwise just use it as a function. You can even use the unary plus operator in this case.
(There is a great deal of discussion about augmenting native objects that I am not going to go into, you can do some research and make up your own mind.)
code :
if (!String.prototype.parseFloat) {
    String.prototype.parseFloat = function () {
        return parseFloat(this);
    }
}

var lat = 123.456789;

console.log(parseFloat(lat.toFixed(2)));
console.log(lat.toFixed(2).parseFloat());
console.log(+lat.toFixed(2));
123.46
123.46 
123.46 
How can I return self and another variable in a python class method while method chaining?

How can I return self and another variable in a python class method while method chaining?


By : Drewski1238
Date : March 29 2020, 07:55 AM
Hope this helps Following the suggestion by @JohnColeman, you can return a special tuple with attribute lookup delegated to your object if it is not a normal tuple attribute. That way it acts like a normal tuple except when you are chaining methods.
You can implement this as follows:
code :
class ChainResult(tuple):
    def __new__(cls, *args):
        return super(ChainResult, cls).__new__(cls, args)
    def __getattribute__(self, name):
        try:
            return getattr(super(), name)
        except AttributeError:
            return getattr(super().__getitem__(0), name)


class Test(object):
    def __init__(self):
        self.hold = None

    def methoda(self):
        self.hold = 'lol'
        return ChainResult(self, 'lol')

    def newmethod(self):
        self.hold = self.hold * 2
        return ChainResult(self, 2)
>>> t = Test()
>>> t.methoda().newmethod()
>>> print(t.hold)
lollol
>>> t, res = t.methoda().newmethod()
>>> print(res)
2
>>> print(isinstance(t.methoda().newmethod(), tuple))
True
class ChainResult(tuple):
    def __new__(cls, *args):
        return super(ChainResult, cls).__new__(cls, args)
    def __getattribute__(self, name):
        try:
            return getattr(super(), name)
        except AttributeError:
            attr = getattr(super().__getitem__(0), name)
            if callable(attr):
                chain_results = super().__getitem__(slice(1, None))
                return lambda *args, **kw: attr(*(chain_results+args), **kw)
            else:
                return attr
class Test:
    ...
    def methodb(self, *args):
        print(*args)
>>> t = Test()
>>> t.methoda().methodb('catz')
lol catz
pass object method as function argument for method chaining in python

pass object method as function argument for method chaining in python


By : Audrey
Date : October 22 2020, 06:10 PM
it should still fix some issue I know similar questions have been asked and answered but i could not find one that really solves my problem. , How about this? Is it what you are looking for?
code :
def myFun(df,fun):
    getattr(df, fun)().anotherfun()
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