用正则表达式擦或者字符串中所有的浮点数，并格式化这些浮点数，保留小数点后2位，最后将格式后的浮点数替换原来的浮点数，同时输出替换后的结果和替换的次数。要求用一条语句实现
import re
'''
1. 表示浮点数的正则表达式 -?\d+(\.\d+)?
2. 格式化浮点数 format
3. 如何替换原来的浮点数 sub subn
'''
result = re.subn('-?\d+(\.\d+)?', '##', 'Pi is 3.141592654, e is 2.71828183, -0.2 + 1.3 = 1.1')
print(result)
print(result[0])
print(result[1])
def fun(matched):
return '<' + matched.group() + '>'
result = re.subn('-?\d+(\.\d+)?', fun, 'Pi is 3.141592654, e is 2.71828183, -0.2 + 1.3 = 1.1')
print(result)
print(result[0])
print(result[1])
def fun(matched):
return format(float(matched.group()), '0.2f')
result = re.subn('-?\d+(\.\d+)?', fun, 'Pi is 3.141592654, e is 2.71828183, -0.2 + 1.3 = 1.1')
print(result)
print(result[0])
print(result[1])
('Pi is ##, e is ##, ## + ## = ##', 5)
Pi is ##, e is ##, ## + ## = ##
5
('Pi is <3.141592654>, e is <2.71828183>, <-0.2> + <1.3> = <1.1>', 5)
Pi is <3.141592654>, e is <2.71828183>, <-0.2> + <1.3> = <1.1>
5
('Pi is 3.14, e is 2.72, -0.20 + 1.30 = 1.10', 5)
Pi is 3.14, e is 2.72, -0.20 + 1.30 = 1.10
5
sub 和 subn 都用于替换字符串中的所有符合条件的子字符串，但sub函数只返回替换后的结果，而subn返回一个元组，元组的第1个元素返回替换后的结果，第2个元素返回替换的次数。
