Preface

The application of regular expressions is mainly investigated from three aspects （ Basic metacharacters / Common regular expressions / use python re Module resolution ）

Table of contents title

• Preface
• One . Basic metacharacters
• Two . Common regular expressions
• 3、 ... and
• summary

One . Basic metacharacters

• Ask what special characters of regular expressions mean

\b
\B
\w
\W
\d
\D
\s
\S
.
*
+
?
|

Please search the above characters again , See what it means

• Greedy mode and non greedy mode
• What characters are needed \ To escape
• Chinese coding range

Two . Common regular expressions

This part of the expression is not unique , Because the needs are different .

• cell-phone number

^1[3-9]\d{
9}$
^1[^0-2]\d{
9}$

Blur the mobile phone number , Blur the middle four digits

import re
phone = '18728147811'
# \1 and \3 It refers to obtaining the matching value of the first group and the third group 
res = re.sub(r"(\d{3})(\d{4})(\d{4})", r"\1****\3", phone)
print(res)
#187****7811

• mailbox

" for example [email protected]"
^[A-Za-z0-9_-][email protected][A-Za-z0-9_-]+(\.[A-Za-z0-9_-]+)+$

• user name

" Alphanumeric underscores support Chinese 4 To 12 position "
^[A-Za-z0-9\u4e00-\u9fa5_]{
4,12}$

• password

 Here are the password registration requirements for CET-4 and CET-6 website
"8-15 Bit length （ Case sensitive ）; Password contains both ： Capital 、 Lowercase letters 、 Numbers and special characters "
" Special characters are [email protected]#$%^&*-_"
^(?=.*\d+)(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#%_-&\$\^\*])^.{8,15}$

3、 ... and

summary