pandas空值处理与插值

# coding:utf-8

import pandas as pd

import numpy as np

import matplotlib.pyplot as plt

from scipy.interpolate import interp1d

data = pd.read_excel('指数.xlsx',header=None,index_col=None)

# 数据信息

# print(data.info())

# 查看空值

isnull = data[1].isnull()

# print(isnull)

# print(data[1])

# 替换空值

data[1] = data[1].fillna('')

# 找出索引

index_ = data[isnull].index.tolist()

# print(index_)

# 去除空列所在行

data = data.drop(index_)

# print(data)

x = data[1]

y = data[0]

# 插值

f1=interp1d(x,y,kind='linear')#线性插值

f2=interp1d(x,y,kind='cubic')#三次样条插值

x_pred=np.arange(1,170,1)

y1=f1(x_pred)

datas = pd.DataFrame([y1,x_pred])

datas.to_excel('new指数.xlsx')

y2=f2(x_pred)

plt.figure(figsize=[12,7])

plt.scatter(x,y,s=30,c='red',label='原始指数')

plt.plot(x_pred,y1,'b--',label='linear interpolation')

# plt.plot(x_pred,y2,'b--',label='cubic')

plt.legend(loc='upper left')

font_size = {'size':13}

plt.ylabel('淘宝指数',font_size)

plt.rcParams['font.sans-serif'] = ['SimHei']  # 设置字体为SimHei显示中文

plt.rcParams['axes.unicode_minus'] = False  # 设置正常显示符号

plt.show()