正則 re.findall 的簡單用法（返回string中所有與pattern相匹配的全部字串，返回形式為數組）
1 findall(pattern, string, flags=0)
import re
Python 正則表達式 re findall 方法能夠以列表的形式返回能匹配的子串
# print (help(re.findall))
# print (dir(re.findall))
findall查找全部r標識代表后面是正則的語句
1 regular_v1 = re.findall(r"docs","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v1) 3 # ['docs']
符號^表示匹配以https開頭的的字符串返回
1 regular_v2 = re.findall(r"^https","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v2) 3 # ['https']
用$符號表示以html結尾的字符串返回,判斷是否字符串結束的字符串
1 regular_v3 = re.findall(r"html$","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v3) 3 # ['html']
# [...]匹配括號中的其中一個字符
1 regular_v4 = re.findall(r"[t,w]h","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v4) 3 # ['th', 'wh']
“d”是正則語法規則用來匹配0到9之間的數返回列表
1 regular_v5 = re.findall(r"\d","https://docs.python.org/3/whatsnew/3.6.html") 2 regular_v6 = re.findall(r"\d\d\d","https://docs.python.org/3/whatsnew/3.6.html/1234") 3 print (regular_v5) 4 # ['3', '3', '6'] 5 print (regular_v6) 6 # ['123']
小d表示取數字0-9，大D表示不要數字，也就是出了數字以外的內容返回
1 regular_v7 = re.findall(r"\D","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v7) 3 # ['h', 't', 't', 'p', 's', ':', '/', '/', 'd', 'o', 'c', 's', '.', 'p', 'y', 't', 'h', 'o', 'n', '.', 'o', 'r', 'g', '/', '/', 'w', 'h', 'a', 't', 's', 'n', 'e', 'w', '/', '.', '.', 'h', 't', 'm', 'l']
“w”在正則里面代表匹配從小寫a到z,大寫A到Z，數字0到9
1 regular_v8 = re.findall(r"\w","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v8) 3 #['h', 't', 't', 'p', 's', 'd', 'o', 'c', 's', 'p', 'y', 't', 'h', 'o', 'n', 'o', 'r', 'g', '3', 'w', 'h', 'a', 't', 's', 'n', 'e', 'w', '3', '6', 'h', 't', 'm', 'l']
“W”在正則里面代表匹配除了字母與數字以外的特殊符號
1 regular_v9 = re.findall(r"\W","https://docs.python.org/3/whatsnew/3.6.html") 2 print (regular_v9) 3 # [':', '/', '/', '.', '.', '/', '/', '/', '.', '.'] 4