Breaking News: Grepper is joining You.com. Read the official announcement!

Principle of iterating on iterables in python

ap_Cooperative_dev answered on August 26, 2022 Popularity 5/10 Helpfulness 1/10

answer Principle of iterating on iterables in python

related python define iterable

Principle of iterating on iterables in python

Comment

 
# 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 5/10 Helpfulness 1/10 Language python

Source: Grepper

Tags: for-loop iterable iterate python

Link to this answer
Share Copy Link

Contributed on Dec 25 2022

ap_Cooperative_dev

0 Answers Avg Quality 2/10

Closely Related Answers

python define iterable

Comment

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

Link to this answer
Share Copy Link

Contributed on Aug 26 2022

Halit Vural

0 Answers Avg Quality 2/10

Principle of iterating on iterables in python

Contents

More Related Answers

Principle of iterating on iterables in python

Closely Related Answers

python define iterable

Grepper

Documentation

Social

Legal

Contact

Oops, You will need to install Grepper and log-in to perform this action.