Normally you can't remove items from a dictionary while you are iterating over it. But if you convert it to a list first, there are no problems.

iterate and pop dict.py

origDict = { 
    'First name': 'Ryan',
    'Last name': 'M',
    'Subject': 'AI',
    'task': 'Cleaning Data'
 }
removedItem = origDict.pop('Last name') # this is normal usage of pop()
print(origDict)
print('value = ' + removedItem)

# now lets loop and pop()
newDict = {} # create a new empty dictionary for us to dump our items() into

# create a list comprehension to build a list from the original dictionary that holds the data we want to process.
tmp = [(k, v) for k, v in origDict.items()]

# now instead of looping through the dictionary,
# we loop through the list 
# and pop items out of the original dictionary as we add items to the new dictionary!
for k, v in tmp:
    # you can process the data here, before you put it in another dictionary.
    newDict[k] = origDict.pop(k, v) 
# in Python, pop() removes an item from a list/dictionary and returns it. In this case we are stuffing it into a new
# dictionary right away.


# Or you can put the comprehension in the loop!
for k, v in [(k, v) for k, v in origDict.items()]:
    newDict[k] = origDict.pop(k, v)

print(origDict)
print(newDict)

I wanted to remove items from a dictionary while iterating over it because I was cleaning data and needed to conditionally process data line by line. The problem was that there was no straightforward way to loop through the lines without processing some lines more than once.

Also, by using a list comprehension you end up only using a few lines of code to complete a pretty complex task.

A different solution would be the following:

newDict = {k: origDict.pop(k) for k in list(origDict.keys())}

A different solution would be the following:

newDict = {k: origDict.pop(k) for k in list(origDict.keys())}

Thanks!
How can I process the values while iterating over that?

One way could be the following:

def my_filter(value):
    # Check here if the item should be removed
    pass

def process(k, value):
    # Define here how to process the item
    pass

newDict = {k: process(k, origDict.pop(k)) for k in list(origDict.keys()) if my_filter(origDict[k])}

One way could be the following:

def my_filter(value):
    # Check here if the item should be removed
    pass

def process(k, value):
    # Define here how to process the item
    pass

newDict = {k: process(k, origDict.pop(k)) for k in list(origDict.keys()) if my_filter(origDict[k])}

Thanks, this is really useful!