regex101: 提取有效小数，如果是0，则只保留1个0

Pro

Group 1(\d+\.([1-9]{3}|[1-9]{2}|[1-9]|0{1}))

\d+a Unicode decimal digit, repeated at least once

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 2([1-9]{3}|[1-9]{2}|[1-9]|0{1})

1st Alternative[1-9]{3}

Character Class[1-9]{3}

{3}matches exactly 3 characters from the set below:

1-9one character from 1 (49₁₀) to 9 (57₁₀)

2nd Alternative[1-9]{2}

Character Class[1-9]{2}

{2}matches exactly 2 characters from the set below:

1-9one character from 1 (49₁₀) to 9 (57₁₀)

3rd Alternative[1-9]

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

4th Alternative0{1}

0{1}the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated exactly 1 time

Group 3(\d*)

\d*a Unicode decimal digit, repeated any number of times

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

25 tokens

Regular Expression

(\d+\.([1-9]{3}|[1-9]{2}|[1-9]|0{1}))(\d*)

New

#提取有效小数的思路：匹配出符合要求的组合不符合要求的组。
#使用sub函数，re.sub(pat,lambda m:m[1],s)
#repl使用函数，传递的参数是pat,所匹配的match对象，提取match对象中符合要求的组即可。
124.1230000012
124.1200003412
123.0000000012
1.2000

Substitution

#提取有效小数的思路：匹配出符合要求的组合不符合要求的组。
#使用sub函数，re.sub(pat,lambda m:m[1],s)
#repl使用函数，传递的参数是pat,所匹配的match对象，提取match对象中符合要求的组即可。
124.1230000012
124.1200003412
123.0000000012
1.2000