“基本统计值计算” 问题分析
1.1 问题分析
基本统计值
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需求：给出一组数，对它们有一个概要理解
总个数，求和，平均值，方差，中位数
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总个数(len)
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求和：for ... in
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平均值：求和/总个数
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方差：各数据与平均数差的平方的和的平均数
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中位数：排序然后 奇数找中间1个，偶数找中间2个取平均
二 “基本统计值计算的实例讲解”
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获取多数据输入
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通过函数分隔功能
def get_nums():
"""获取数据"""
nums = []
num = input('请输入数字：').strip()
while num != '':
nums.append(num)
num = input('请输入数字:').strip()
return nums
def get_len(nums):
"""获取长度"""
count = 0
for num in nums:
count += 1
return count
# nums = get_num()
# print(get_len(nums))
def get_add(nums):
"""求和"""
sum = 0
for num in nums:
sum += eval(num)
return sum
# nums = get_num()
# print(get_add(nums))
def get_mean(nums):
"""求平均数"""
sum = 0
for num in nums:
sum += eval(num)
mean = sum/get_len(nums)
return mean
# nums = get_nums()
# print(get_mean(nums))
def get_var(nums,mean):
"""求方差"""
sum = 0
for num in nums:
sum += (mean-eval(num))**2
var = sum / get_len(nums)
return var
# nums = get_nums()
# print(get_var(nums,get_mean(nums)))
def get_median(nums):
"""求中位数"""
nums_sort = sorted(nums)
size = get_len(nums)
if size % 2 == 0:
med = (eval(nums_sort[size // 2 - 1]) + eval(nums_sort[size // 2])) / 2
else:
med = eval(nums_sort[size//2])
return med
nums = get_nums()
print(get_median(nums))
优化版的统计值计算
def get_nums():
"""获取数据"""
nums = []
num = input('请输入数字：').strip()
while num != '':
nums.append(num)
num = input('请输入数字:').strip()
return nums
def get_len(nums):
"""获取长度"""
count = 0
for num in nums:
count += 1
return count
# nums = get_num()
# print(get_len(nums))
def get_add(nums):
"""求和"""
sum = 0
for num in nums:
sum += eval(num)
return sum
# nums = get_num()
# print(get_add(nums))
def get_mean(nums):
"""求平均数"""
sum = 0
for num in nums:
sum += eval(num)
mean = sum/get_len(nums)
return mean
# nums = get_nums()
# print(get_mean(nums))
def get_var(nums,mean):
"""求方差"""
sum = 0
for num in nums:
sum += (mean-eval(num))**2
var = sum / get_len(nums)
return var
# nums = get_nums()
# print(get_var(nums,get_mean(nums)))
def get_median(nums):
"""求中位数"""
nums_sort = sorted(nums)
size = get_len(nums)
if size % 2 == 0:
med = (eval(nums_sort[size // 2 - 1]) + eval(nums_sort[size // 2])) / 2
else:
med = eval(nums_sort[size//2])
return med
# nums = get_nums()
# print(get_median(nums))
def run():
nums = get_nums()
l1 = ['长度','和','平均值','方差','中位数']
while True:
print("欢迎来到数学计算器".center(20,"-"))
print("""
1.求长度
2.求和
3.求平均值
4.求方差
5.求中位数
6:退出程序
""")
choice = input("请输入你的需求：").strip()
result = 0
if choice == '1':
result = get_len(nums)
elif choice == '2':
result = get_add(nums)
elif choice == '3':
result = get_mean(nums)
elif choice == '4':
result = get_var(nums,get_mean(nums))
elif choice == '5':
result = get_median(nums)
elif choice == '6':
return
else:
print('输入格式有误')
print(result)
print(f"{l1[eval(choice) -1]}:{result}")
run()