计算两个数字之间的百分比变化（Python）
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Calculating change in percentage between two numbers (Python)
提问by
I have a list of prices where I am trying to calculate the change in percentage of each number. I calculated the differences with
我有一个价格列表，我试图在其中计算每个数字的百分比变化。我计算了差异
prices = [30.4, 32.5, 31.7, 31.2, 32.7, 34.1, 35.8, 37.8, 36.3, 36.3, 35.6]
def f():
for i in range(len(prices)):
print(prices[i]-prices[i-1])
Which returns the differences like
返回的差异如下
2.1
-0.8
-0.5
...
I know the change in percentage would be ((i-(i-1))/(i-1) *100, but I don't know how to incorporate that into the script. Any help would be much appreciated.
我知道百分比的变化是 ((i-(i-1))/(i-1) *100，但我不知道如何将其合并到脚本中。任何帮助将不胜感激。
采纳答案by arshajii
Try this:
尝试这个：
prices = [30.4, 32.5, 31.7, 31.2, 32.7, 34.1, 35.8, 37.8, 36.3, 36.3, 35.6]
for a, b in zip(prices[::1], prices[1::1]):
print 100 * (b - a) / a
Edit:If you want this as a list, you could do this:
编辑：如果你想把它作为一个列表，你可以这样做：
print [100 * (b - a) / a for a, b in zip(prices[::1], prices[1::1])]
回答by badgley
If you haven't been exposed to the pandas library in Python (http://pandas.pydata.org/), you should definitely check it out.
如果您还没有接触过 Python 中的 pandas 库 (http://pandas.pydata.org/)，那么您一定要检查一下。
Doing this is as easy as:
这样做很简单：
import pandas as pd
prices = [30.4, 32.5, 31.7, 31.2, 32.7, 34.1, 35.8, 37.8, 36.3, 36.3, 35.6]
price_series = pd.Series(prices)
price_series.pct_change()
回答by Norbert Wesolowski
Though definitely not the most elegant way, if you'd like to define a function it would look something like this:
虽然绝对不是最优雅的方式，但如果你想定义一个函数，它看起来像这样：
def pctc(Q):
output = [0]
for i in range(len(Q)):
if i > 0:
increase = Q[i]-Q[i-1]
percentage = (increase/Q[i]) * 100
output.append(percentage)
return(output)
There's probably even a better way to do that function, but it's clear at least. :))
甚至可能有更好的方法来执行该功能，但至少很清楚。:))
