如何查找字典值的长度？
在Python中，字典是无序数据值的集合。字典也是可变的和索引的。字典包含键：值对，它们写在大括号内。每个键：值对将键映射到其关联的值。
这里我们使用 isinstance() 方法来检查值的类型是否是列表、int、str、元组等。 isinstance()方法是Python中的内置方法。如果传递的对象是给定类的实例，它返回一个布尔值。
让我们讨论查找字典值长度的不同方法。
注意：在以下方法中，字符串值的长度取为 1。
方法 #1使用 in运算符
示例：1
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'a':[1, 2, 3],
'b'🙁1, 2, 3),
'c':5,
'd':"nopqrs",
'e':["A", "B", "C"]}
# Initialize count
count = 0
# using in operator
for k in dict1:
# Check the type of value
# is int or not
if isinstance(dict1[k], int):
count += 1
# Check the type of value
# is str or not
elif isinstance(dict1[k], str):
count += 1
else:
count += len(dict1[k])
print("The total length of value is:", count)
# Driver Code
if __name__ == '__main__':
main()
输出：
The total length of value is: 11示例：2
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'A':"abcd",
'B':set([1, 2, 3]),
'C'🙁12, "number"),
'D':[1, 2, 4, 5, 5, 5]}
# Create a empty dictionary
dict2 = {}
# using in operator
for k in dict1:
# Check the type of value
# is int or not
if isinstance(dict1[k], int):
dict2[k] = 1
# Check the type of value
# is str or not
elif isinstance(dict1[k], str):
dict2[k] = 1
else:
dict2[k] = len(dict1[k])
print("The length of values associated\
with their keys are:", dict2)
print("The length of value associated\
with key 'B' is:", dict2['B'])
# Driver Code
if __name__ == '__main__':
main()
输出：
The length of values associated with their keys are: {‘A’: 1, ‘B’: 3, ‘C’: 2, ‘D’: 6}
The length of value associated with key ‘B’ is: 3
方法 #2使用列表推导
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'a':[1, 2, 3],
'b'🙁1, 2, 3),
'c':5,
'd':"nopqrs",
'e':["A", "B", "C"]}
# using list comprehension
count = sum([1 if isinstance(dict1[k], (str, int))
else len(dict1[k])
for k in dict1])
print("The total length of values is:", count)
# Driver Code
if __name__ == '__main__':
main()
输出：
The total length of values is: 11方法#3使用字典理解
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'A': "abcd",
'B': set([1, 2, 3]),
'C': (12, "number"),
'D': [1, 2, 4, 5, 5, 5]}
# using dictionary comprehension
dict2 = {k:1 if isinstance(dict1[k], (str, int))
else len(dict1[k])
for k in dict1}
print("The length of values associated \
with their keys are:", dict2)
print("The length of value associated \
with key 'B' is:", dict2['B'])
# Driver Code
if __name__ == '__main__':
main()
输出：
The length of values associated with their keys are: {‘A’: 1, ‘B’: 3, ‘C’: 2, ‘D’: 6}
The length of value associated with key ‘B’ is: 3
方法 #4使用 dict.items()
示例：1
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'a':[1, 2, 3],
'b'🙁1, 2, 3),
'c':5,
'd':"nopqrs",
'e':["A", "B", "C"]}
# Initialize count
count = 0
# using dict.items()
for key, val in dict1.items():
# Check the type of value
# is int or not
if isinstance(val, int):
count += 1
# Check the type of value
# is str or not
elif isinstance(val, str):
count += 1
else:
count += len(val)
print("The total length of value is:", count)
# Driver code
if __name__ == '__main__':
main()
输出：
The total length of values is: 11
示例：2
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'A': "abcd",
'B': set([1, 2, 3]),
'C': (12, "number"),
'D': [1, 2, 4, 5, 5, 5]}
# Create a empty dictionary
dict2 = {}
# using dict.items()
for key, val in dict1.items():
# Check the type of value
# is int or not
if isinstance(val, int):
dict2[key] = 1
# Check the type of value
# is str or not
elif isinstance(val, str):
dict2[key] = 1
else:
dict2[key] = len(val)
print("The length of values associated \
with their keys are:", dict2)
print("The length of value associated \
with key 'B' is:", dict2['B'])
# Driver Code
if __name__ == '__main__':
main()
输出：
The length of values associated with their keys are: {‘A’: 1, ‘B’: 3, ‘C’: 2, ‘D’: 6}
The length of value associated with key ‘B’ is: 3
方法 #5使用 enumerate()
示例：1
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'a':[1, 2, 3],
'b'🙁1, 2, 3),
'c':5,
'd':"nopqrs",
'e':["A", "B", "C"]}
# Initialize count
count = 0
# using enumerate()
for k in enumerate(dict1.items()):
# Check the type of value
# is int or not
if isinstance(k[1][1], int):
count += 1
# Check the type of value
# is str or not
elif isinstance(k[1][1], str):
count += 1
else:
count += len(k[1][1])
print("The total length of value is:", count)
# Driver Code
if __name__ == '__main__':
main()
输出：
The total length of value is: 11示例：2
# Python program to find the
# length of dictionary values
def main():
# Defining the dictionary
dict1 = {'A': "abcd",
'B': set([1, 2, 3]),
'C': (12, "number"),
'D': [1, 2, 4, 5, 5, 5]}
# Create a empty dictionary
dict2 = {}
# using enumerate()
for k in enumerate(dict1.items()):
# Check the type of value
# is int or not
if isinstance(k[1][1], int):
dict2[k[1][0]] = 1
# Check the type of value
# is str or not
elif isinstance(k[1][1], str):
dict2[k[1][0]] = 1
else:
dict2[k[1][0]] = len(k[1][1])
print("The length of values associated\
with their keys are:", dict2)
print("The length of value associated \
with key 'B' is:", dict2['B'])
# Driver Code
if __name__ == '__main__':
main()
输出：
The length of values associated with their keys are: {‘A’: 1, ‘B’: 3, ‘C’: 2, ‘D’: 6}
The length of value associated with key ‘B’ is: 3