辞書のリストからキーの値が一致する数をカウントする方法

import collections

# 辞書のリスト
data = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 25},
    {"name": "Charlie", "age": 30},
    {"name": "David", "age": 42},
]

# 'age'の値を数える
age_counter = collections.Counter(item["age"] for item in data)
print(age_counter) # Counter({30: 2, 25: 1, 42: 1})

# 'age'が30の数を取得
count_30 = age_counter[30]
print(count_30)  # 2

import collections

# 辞書のリスト
data = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 25},
    {"name": "Charlie", "age": 30},
    {"name": "David", "age": 42},
]

# 'name'の値を数える
name_counter = collections.Counter(item["name"] for item in data)
print(name_counter) # Counter({'Alice': 1, 'Bob': 1, 'Charlie': 1, 'David': 1})

count_alice = name_counter['Alice']
print(count_alice)  # 1

import collections

# 空のリスト
data = [
]

name_counter = collections.Counter(item["age"] for item in data)
print(name_counter) # Counter()

# 'age'が0の数を取得
count_zero = name_counter[0]
print(count_zero)  # 0

# 辞書のリスト
data = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 5},
    {"name": "Charlie", "age": 30},
    {"name": "David", "age": 0},
    {"name": "David", "age": 6},
]

sum_david = sum(1 for item in data if item["name"] == 'David')
print(sum_david) # 2

# 辞書のリスト
data = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 5},
    {"name": "Charlie", "age": 30},
    {"name": "David", "age": 0},
    {"name": "David", "age": 6},
]

age_num = sum(1 for item in data if item["age"] != 0)
print(age_num) # 4

# 辞書のリスト
data = [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 5},
    {"name": "Charlie", "age": 30},
    {"name": "David", "age": 0},
]

sum_age = sum(item["age"] for item in data)
print(sum_age) # 65

sum_age = sum(item['age'] for item in data if item["age"] > 5)
print(sum_age) # 60