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Principle of iterating on iterables in python

ap_Cooperative_dev answered on August 26, 2022 Popularity 3/10 Helpfulness 1/10

answer Principle of iterating on iterables in python

related python define iterable

Principle of iterating on iterables in python

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# imp: iterable of a for loop is the object that the reference/variable  
# we write after in keyword of for loop pointed to initially  

# the iterable that we iterate on using for loop 
# should never change in place till all iterations over iterable ends 
# SO IF ITERABLE IS CHANGING INSIDE THE FOR LOOP- iterate over it's copy:
a=[1,2,3,4]
for x in list(a):
      a.pop()
      print(x,a)
# imp note : a was changing due to use of pop() method in abobe for loop 
# but note that the below code doesn't change the iterable in place:
a=[1,2,3,4]
for z in a:
    a=a[:len(a)-1] #we dont change a in place but assign it to new object
    print(z,a)
# both above codes give SAME OUTPUT. 

# note: dict and set are not indexed(slicing not possible) so either use 
# *,** or methods like pop etc but then relative ordering of elements 
# will change each time we use *,** or methods like pop etc.
# So if iterating on these 2 as iterables in a for loop know that 
# iterable's relative order of elements will be different than set/dict 
# object inside for loop which will be changed by methods,*,** etc
# OrderedDict instead of dict can used to preserve the relative order.

# note: in case of while loop we don't iterate over any iterable 
# but do unkown number of iterations till a fixed condition is True

Popularity 3/10 Helpfulness 1/10 Language python

Source: Grepper

Tags: for-loop iterable iterate python

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Contributed on Dec 25 2022

ap_Cooperative_dev

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python define iterable

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class Reverse:
    """Iterator for looping over a sequence backwards."""
    def __init__(self, data):
        self.data = data
        self.index = len(data)

    def __iter__(self):
        return self

    def __next__(self):
        if self.index == 0:
            raise StopIteration
        self.index = self.index - 1
        return self.data[self.index]

Popularity 10/10 Helpfulness 2/10 Language python

Source: docs.python.org

Tags: iterable iterabl

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Contributed on Aug 26 2022

Halit Vural

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Principle of iterating on iterables in python

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Principle of iterating on iterables in python

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python define iterable

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