如何使用 python 计算值列表中的百分比增加或减少

Question

我想计算列表中增加或减少的百分比变化。 这是我的列表年龄 = [20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 13.4, 140.9]

这是我的代码

def percent_change_in_naira(value):
  try:
    for i in value:
        if old_num > new_num:
          ((((old_num-new_num)/old_num)*100))
        elif old_num == new_num:
          0
        else:
          ((((new_num-old_num)/old_num)*100))
    return value
  except ZeroDivisionError:
        return 0

如何将“new_num”分配给上面列表中的新号码，将“old_num”分配给上面列表中的前一个号码？

提前致谢

Answer 1

在 Python 中（如评论中@sahasrara62 所建议）

ages = [20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 13.4, 140.9]

changes = []
for x1, x2 in zip(ages[:-1], ages[1:]):
    try:
        pct = (x2 - x1) * 100 / x1
    except ZeroDivisionError:
        pct = None
    changes.append(pct)

# [50.2463054187192,
#  -33.44262295081967,
#  124.13793103448275,
#  11.208791208791212,
#  -41.699604743083,
#  -54.576271186440685,
#  951.4925373134328]

使用 numpy

import numpy as np

ages = np.array([20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 
                 13.4, 140.9])
diff = ages[1:] - ages[:-1]
changes = diff / ages[1:] * 100

# [ 50.24630542 -33.44262295 124.13793103  11.20879121
#  -41.69960474 -54.57627119 951.49253731]

使用 Pandas

import pandas as pd

ages = pd.Series([20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 
                  13.4, 140.9])
changes = ages.pct_change() * 100

# 0           NaN
# 1     50.246305
# 2    -33.442623
# 3    124.137931
# 4     11.208791
# 5    -41.699605
# 6    -54.576271
# 7    951.492537
# dtype: float64

Answer 2

你可以试试这个：Will get current and next value by index value of list

def percent_change_in_naira(value):
    output = []
    try:
        for index,i in enumerate(range(len(value))):
            if i == 0:
                output.append(i)
            else:
                old_num = value[index-1]
                new_num = value[index]                    
                output.append(round((((old_num-new_num)/old_num)*100), 3))
    except ZeroDivisionError:
            output.append(0)
    return output

预计 output 是：

[0, -50.246, 33.443, -124.138, -11.209, 41.7, 54.576, -951.493]

Answer 3

您可以使用列表推导：

i = [20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 13.4, 140.9]

i = [0]+[(i[n+1]-i[n])/i[n]*100 if i[n] else 0 for n in range(len(i)-2)]

print(i)

Output：

[0, 50.2463054187192, -33.44262295081967, 124.13793103448273, 11.208791208791212, -41.69960474308301, -54.576271186440685]

Answer 4

计算运行百分比变化的最简单（也是最快）的方法是使用 numpy.array。

import numpy as np
li = np.array([20.3, 30.5, 20.3, 45.5, 50.6, 29.5, 13.4, 140.9])

perc=[0.0]+list(np.round((li[1:]/li[:-1]-1)*100,decimals=1))

print(perc)

Output：

[0.0, 50.2, -33.4, 124.1, 11.2, -41.7, -54.6, 951.5]

请注意，如果您除以零，numpy 将自动输入“inf”作为结果。