python数据分析（十二）

# -*- coding: utf-8 -*-

import pandas as pd

from pandas import Series, DataFrame

import numpy as np

a=[98,83,65,72,79,76,75,94,91,77,63,83,89,69,64,78,63,86,91,72,71,72,70,80,65,70,62,74,71,76]

mean(a)

mean(np.sort(a)[14:16])

np.sort(a)

#求众数的函数

def get_mode(arr):

mode = [];

arr_appear = dict((a, arr.count(a)) for a in arr);  # 统计各个元素出现的次数

if max(arr_appear.values()) == 1:  # 如果最大的出现为1

return;  # 则没有众数

else:

for k, v in arr_appear.items():  # 否则，出现次数最大的数字，就是众数

if v == max(arr_appear.values()):

mode.append(k);

return mode;

get_mode(a)

var(a)

std(a)

a=Series(a)

a.skew()

a.kurt()

a.describe()

df = DataFrame({'data1' : np.random.randn(5),

'data2' : np.random.randn(5)})

df.cov()

df.corr()

###假设检验

from scipy import stats as ss

df=DataFrame({'data':[10.1,10,9.8,10.5,9.7,10.1,9.9,10.2,10.3,9.9]})

ss.ttest_1samp(a = df, popmean = 10)