python正規表示式01

正規表示式,又稱規則表示式,英文名為regular expression,在**中常簡寫為regex、regexp或re,是電腦科學的乙個概念。正則表通常被用來檢索、替換那些符合某個模式(規則)的文字。 python 中正規表示式使用re模組。

match() 函式試圖從字串的起始部分對模式進行匹配。如果匹配成功，就返回乙個匹配物件；如果 匹配失敗，就返回 none，匹配物件的 group()方法能夠用於顯示那個成功的匹配。

import re

m = re.match(,) 
m.group()-
----
----
----
----
----
---

import re

m = re.match(
'table',)
if m is
notnone
:    m.group(
)else
:print
("can't find it")-
----
----
----
can't find it

import re

m = re.search(
'table',)
if m is
notnone
:print
(m.group())
else
:print
("can't find it")-
----
----
----
table

import re

bt='pen|on|table'
m = re.match(bt,
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.match(bt,
'pen on the table'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(bt,
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(bt,
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.match(bt,
)if m is
notnone
:print
(m.group())
else
:print
("can't find it")-
----
----
----
can't find it
penon
table
can't find it

import re

anyend=
'.pple'
m = re.match(anyend,
)#查詢首字母後的字元
if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(anyend,
)#查詢首字母後的字元
if m is
notnone
:print
(m.group())
else
:print
("can't find it")-
----
----
----

import re

anyend=
'.end'
m = re.match(anyend,
'end'
)#不能匹配
if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(anyend,
'i like\nend'
)#換行後不能匹配
if m is
notnone
:print
(m.group())
else
:print
("can't find it")-
----
----
---can't find it
can't find it

import re

anyend=
'.end'
m = re.search(anyend,
'in the end.'
)#試試這樣
if m is
notnone
:print
(m.group())
#輸出結果的前面會有乙個空格 
else
:print
("can't find it")-
----
----
--- end

import re

patt314 =
'3.14'
# 表示正規表示式的點號  
pi_patt =
'3\.14'
# 表示字面量的點號 (dec. point) 
m = re.search(patt314,
'3.14'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(patt314,
'3014'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(patt314,
'3514'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(pi_patt,
'3.14'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it"
)m = re.search(pi_patt,
'3014'
)if m is
notnone
:print
(m.group())
else
:print
("can't find it")-
----
----
---3.14
3014
3514
3.14
can't find it

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