用Python定义浮点数的精度

Question

我这里有一些python代码

代码：

 t = 1
 xt = array([ -1.,-1. ])

 xt[0] = theta[0][0]* P_all_States[t-1][0] + theta[1][0]*P_all_States[t-1][1]

 xt[1] = theta[0][1]* P_all_States[t-1][0] + theta[1][1]*P_all_States[t-1][1]

 P_all_States[t][0] = xt[0]
 P_all_States[t][1] = xt[1]
 print ("Added probability distribution for time t = " + str(t) + " to P_all_States")
 print P_all_States

输出：

Added probability distribution for time t = 1 to P_all_States [[0.6, 0.4], [0.62000000000000011, 0.38000000000000006], [-1.0, -1.0], [-1.0, -1.0], [-1.0, -1.0], [-1.0, -1.0]]

如何使浮点数四舍五入为两个重要数字？

这些都是浮点数，所以我不想把它们转换成字符串，我希望它们保持浮点数

谢谢

Answer 1

要转换整个列表，请将@Zashas answer与：

rounded = [ [round(a[0],2), round(a[1],2)] for a in P_all_States ]