NumPy中的统计函数
sum(a,axis = None):根据给定轴axis计算数组a相关元素之和,axis整数或元组
mean(a,axis = None):根据给定轴axis计算数组a相关元素的期望,axis整数或元组
average(a,axis = None,weights = None):根据给定轴axis计算数组a相关元素的加权平均值
std(a,axis = None):根据给定轴axis计算数组a相关元素的标准差
var(a,axis = None):根据给定轴axis计算数组a相关元素的方差
np.min(a,axis = None)或a.min(axis = None),np.max(a,axis = None)或a.max(axis = None):计算数组a中元素的最小值、最大值
import numpy as np a = np.array([[1,5,3],[4,2,6]]) print(a.min()) #无参,所有中的最小值 print(a.min(0)) # axis=0; 每列的最小值 print(a.min(1)) # axis=1;每行的最小值
np.argmin(a,axis = None)或a.argmin(axis = None),np.argmax(a,axis = None)或a.argmax(axis = None):计算数组a中元素的最小值、最大值的降一维后下标
unravel_index(index,shape):根据shape将一维下标index转换成多维下标a = np.arange(15).reshape(3,5) np.random.shuffle(a) print(a) np.argmin(a) index = np.unravel_index(np.argmin(a),a.shape) print(index)
ptp(a):计算数组a中元素最大值与最小值的差
median(a):计算数组a中元素的中位数