您可以将round
内置函数与列表理解一起使用:
我有几个多边形的坐标列表,如下所示:
l_b = [[[57.5, 2.875],
[83.75, 4.1875],
[83.75, 18.70923913043478],
[57.50000000000001, 18.70923913043478],
[57.5, 2.875]],
[[83.75, 18.70923913043478],
[57.50000000000001, 18.70923913043478],
[57.5, 34.08695652173913],
[83.75, 34.54347826086956],
[83.75, 18.70923913043478]],
[[0.0, 0.0],
[18.125, 0.90625],
[18.125, 16.70108695652174],
[-2.530467720685112, 16.70108695652174],
[0.0, 0.0]],
[[18.125, 16.70108695652174],
[-2.530467720685112, 16.70108695652174],
[-5.0, 33.0],
[18.125, 33.40217391304348],
[18.125, 16.70108695652174]]]
如何在保持格式的同时将列表中的所有数字四舍五入到小数点后2位?
我尝试过l_b = [ '%.2f' % elem for elem in l_b ]
,但它给了我TypeError: must be real number, not list
您可以使用递归如果您的列表是任意嵌套的。如果您的列表是3层嵌套的,则使用@Guy的答案或@mrEvgenX的答案。
In [51]: def recur(lst):
...: if isinstance(lst,float):
...: return '%.2f'%lst #use round(lst,2) if you want float instead of string.
...: else:
...: return [recur(i) for i in lst]
In [52]: recur(l_b)
输出
[[['57.50', '2.88'],
['83.75', '4.19'],
['83.75', '18.71'],
['57.50', '18.71'],
['57.50', '2.88']],
[['83.75', '18.71'],
['57.50', '18.71'],
['57.50', '34.09'],
['83.75', '34.54'],
['83.75', '18.71']],
[['0.00', '0.00'],
['18.12', '0.91'],
['18.12', '16.70'],
['-2.53', '16.70'],
['0.00', '0.00']],
[['18.12', '16.70'],
['-2.53', '16.70'],
['-5.00', '33.00'],
['18.12', '33.40'],
['18.12', '16.70']]]
您有3个嵌套列表级别,因此需要向下钻取
l_b = [[['%.2f' % y[0], '%.2f' % y[1]] for y in x] for x in l_b]
@ Guy的解决方案有一个副作用。它使列表变平。
这可能更合适。
l_b = [[['%.2f' % z for z in y] for y in x] for x in l_b]
您可以将map()
与round()
一起使用。 round()
可以将所需的位数作为第二个参数。
for polygon in l_b:
for point in polygon:
point[:] = map(lambda x: round(x, 2), point)
尝试这种numpy方法:
l_b = np.array( [[[57.5, 2.875],
[83.75, 4.1875],
[83.75, 18.70923913043478],
[57.50000000000001, 18.70923913043478],
[57.5, 2.875]],
[[83.75, 18.70923913043478],
[57.50000000000001, 18.70923913043478],
[57.5, 34.08695652173913],
[83.75, 34.54347826086956],
[83.75, 18.70923913043478]],
[[0.0, 0.0],
[18.125, 0.90625],
[18.125, 16.70108695652174],
[-2.530467720685112, 16.70108695652174],
[0.0, 0.0]],
[[18.125, 16.70108695652174],
[-2.530467720685112, 16.70108695652174],
[-5.0, 33.0],
[18.125, 33.40217391304348],
[18.125, 16.70108695652174]]])
数组的形状为(4,5,2)
应用映射将小数点后两位取整]
a=list(map(lambda x :round(x,2),l_b.flatten() ))
转换回原始形状
np.array(a).reshape(4,5,2)
或
Georgy建议的一种更简单的方法>
l_b.round(2)
您可以将round
内置函数与列表理解一起使用:
l_b = [[[round(e, 2) for e in j] for j in i] for i in l_b]
您可以将round
内置函数与列表理解一起使用: