re.match search findall

import re

string = 'dfkv ddjv dchsk fafchiruc jrjkv dchsk'
print(re.match('fa',string))  #開頭開始匹配，開頭匹配到就返回，開頭沒有就返回None
print(re.match('df',string))
print('---------------')
print(re.search('ch',string))  #匹配全文  找到第一個位置就返回，返回找的的起始和結束位子
print(re.search('df',string))
print('---------------------')
print(re.findall('ch',string)) #返回找的的全部，返回列表的形式

# None
# <_sre.SRE_Match object; span=(0, 2), match='df'>
# ---------------
# <_sre.SRE_Match object; span=(11, 13), match='ch'>
# <_sre.SRE_Match object; span=(0, 2), match='df'>
# ---------------------
# ['ch', 'ch', 'ch']

string = 'fsv vv  vbkmv rjn'
print(re.sub('v','5',string))
print(re.subn('v','5',string))
print(type(re.sub('v','5',string)))
print(type(re.subn('v','5',string)))
# fs5 55  5bkm5 rjn
# ('fs5 55  5bkm5 rjn', 5)
# <class 'str'>
# <class 'tuple'>