Python 计算具有多个值的键的平均值

我有以下嵌套数组：

[["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

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我想计算每个人的平均数。例如，Diane的平均值=35（50+20）/2。

尝试以下方法，使用临时的

defaultdict

存储每个人的条目总数和数量：

from collections import defaultdict

values = [["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

stats = defaultdict(lambda: {"num_entries": 0, "total": 0})

for name, value in values:
    stats[name]["num_entries"] += 1
    stats[name]["total"] += value

averages = {}

for name, stat in stats.items():
    averages[name] = stat["total"] / stat["num_entries"]

print(averages)

输出指令：

{'Diane'：35.0，'Bion'：32.5，'Jack'：25.0}

此功能：

values = [["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]
people = {}
for i in values: # type(i) -> list. i[0] are names, i[1] are values.
    if i[0] in people: # Check if it have the key.
        people[i[0]][0] += i[1] # Add value.
        people[i[0]][1] += 1 # Add 1 to entries count.
    else:
        people.update({i[0]:[i[1],1]}) # A new entry is made.
result = {i:people[i][0]/people[i][1] for i in people}
print(result)

输出：

{'Diane': 30.0, 'Bion': 32.5, 'Jack': 25.0}

---

基本上，我制作了一本字典（人物），名字像键和列表（条目的总数和数量），检查名字是否重复（在第一个单词中）。然后，我制作了另一个字典，名字如键和上一个字典列表内容的划分。

这将根据您的要求返回一个嵌套列表

代码：

# Nested list of name and age
t = [["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

# Create a dictionary to combine all ages for a name
dict = {}
for k in t:
    if k[0] in dict:
        dict[k[0]].append(k[1])
    else:
        dict[k[0]] = [k[1]]

# Calculate average for each name
t2 = [] 
for key, value in dict.items():
    avg = sum(value) / float(len(value))
    t2.append([key, avg])

print(t2)

[["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

[['Diane', 35.0], ['Bion', 32.5], ['Jack', 25.0]]

输入：

# Nested list of name and age
t = [["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

# Create a dictionary to combine all ages for a name
dict = {}
for k in t:
    if k[0] in dict:
        dict[k[0]].append(k[1])
    else:
        dict[k[0]] = [k[1]]

# Calculate average for each name
t2 = [] 
for key, value in dict.items():
    avg = sum(value) / float(len(value))
    t2.append([key, avg])

print(t2)

[["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

[['Diane', 35.0], ['Bion', 32.5], ['Jack', 25.0]]

输出：

# Nested list of name and age
t = [["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

# Create a dictionary to combine all ages for a name
dict = {}
for k in t:
    if k[0] in dict:
        dict[k[0]].append(k[1])
    else:
        dict[k[0]] = [k[1]]

# Calculate average for each name
t2 = [] 
for key, value in dict.items():
    avg = sum(value) / float(len(value))
    t2.append([key, avg])

print(t2)

[["Diane", 20],["Bion",25],["Jack",30],["Bion",40],["Diane",50],["Jack",20]]

[['Diane', 35.0], ['Bion', 32.5], ['Jack', 25.0]]

---

这是一个嵌套列表，既不是数组也不是dict。