Created: January-30, 2021 | Updated: February-07, 2021 In this tutorial, we will discuss how to count the number of keys in a Python dictionary using the The Output: We can also pass the dictionary directly to the Output:
We can also create our own function to calculate the number of Python keys. We initialize a variable to 0, iterate over the dictionary using the Output: The len[] Function to Count the Number of Keys in a Python Dictionarylen[] function and also create our own function for the same purpose.Use the
len[] Function to Count the Number of Keys in a Python Dictionarylen[] function in Python is used to return the total number of items
present in an object. We can use the keys[] method of the dictionary to get a list of all the keys in the dictionary and count the total number using len[].dict1 = {'a':1,'b':2,'c':3}
print[len[dict1.keys[]]]
3
len[] function, which returns the distinct total entries in the dictionary, which is the same as the number of the keys.dict1 = {'a':1,'b':2,'c':3}
print[len[dict1]]
3
Create a User-Defined Function to Calculate the Number of Keys in a Python Dictionary
enumerate[], increment the variable in every iteration, and return it. The following code will explain this.dict1 = {'a':1,'b':2,'c':3}
def count_keys[dict]:
count = 0
for i in enumerate[dict]:
count += 1
return count
print[count_keys[dict1]]
3
enumerate[]
function returns an enumerate object that attaches a counter variable to the dictionary’s keys and makes looping over the dictionary easily.Related Article - Python Dictionary
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In Python, dictionary is a collection which is unordered, changeable and indexed. Dictionaries are written with curly brackets, and they have keys and values. It is used to hash a particular key. A dictionary has multiple key:value pairs. There can be multiple pairs where value corresponding to a key is a list. To check that the value is a list or not we use the isinstance[] method which is inbuilt in Python. isinstance[] method takes two parameters:
object - object to be checked classinfo - class, type, or tuple of classes and types
It return a boolean whether the object is an instance of the given class or not. Let’s discuss different methods to count number of items in a dictionary value that is a list. Method #1 Using in operator
Python3
def main[]:
d = {'A' : [1, 2, 3, 4, 5, 6, 7, 8, 9],
'B'
: 34,
'C' : 12,
'D' : [7, 8, 9, 6, 4] }
count = 0
for x in d:
if isinstance[d[x], list]:
count += len[d[x]]
print[count]
if __name__ == '__main__':
main[]
Method #2: Using list comprehension
Python3
def main[]:
d = {'A' : [1, 2, 3, 4, 5, 6, 7, 8, 9],
'B' : 34,
'C' : 12,
'D'
: [7, 8, 9, 6, 4] }
print[sum[[len[d[x]] for x in d if isinstance[d[x], list]]]]
if __name__ == '__main__':
main[]
Method #3: Using dict.items[]
Python3
def main[]:
d =
{ 'A' : [1, 2, 3, 4, 5, 6, 7, 8, 9],
'B' : 34,
'C' : 12,
'D' : [7, 8, 9, 6, 4] }
count = 0
for key, value in d.items[]:
if
isinstance[value, list]:
count += len[value]
print[count]
if __name__ == '__main__':
main[]
Method #4: Using enumerate[]
Python3
def main[]:
d = {'A'
: [1, 2, 3, 4, 5, 6, 7, 8, 9],
'B' : 34,
'C' : 12,
'D' : [7, 8, 9, 6, 4] }
count = 0
for
x in enumerate[d.items[]]:
if isinstance[x[1][1], list]:
count += len[x[1][1]]
print[count]
if __name__ == '__main__':
main[]
Method#5: Using values[],find[] and type[].
Python3
def main[]:
d =
{'A' : [1, 2, 3, 4, 5, 6, 7, 8, 9],
'B' : 34,
'C' : 12,
'D' : [7, 8, 9, 6, 4] }
count = 0
for x in list[d.values[]]:
type1=str[type[x]]
if[type1.find['list']!=-1]:
count+=len[x]
print[count]
if __name__ == '__main__':
main[]