python字串的增刪改查

標籤：luchangshan5200

字串增加

1. 直接 +

name = ‘de8ug‘

city = ‘beijing‘

info = name + ‘ ‘ + city

info

‘de8ug beijing‘

2. % 預留位置替換

‘name: %s, place: %s‘%(name,city)                           

‘name: de8ug, place: beijing‘

3. {}format 變數替換{} 或者 參數賦值

‘name:{},place:{}‘.format(name,city)                        

‘name:de8ug,place:beijing‘

‘name:{nameA},place:{placeA}‘.format(nameA=name,placeA=city)  

‘name:de8ug,place:beijing‘

4. f-string

f‘name:{name},place:{city}‘

‘name:de8ug,place:beijing‘

5. ‘ lilei said "where is han×××" ‘
   或者 " lilei said ‘where is han××ב " #雙引號內加單引號或者單引號內加雙引號

刪除字串

name = ‘de8ug‘

name = ‘‘

name

‘‘

字串修改

name = ‘de8ug‘

name.upper()  #大寫

‘DE8UG‘

name.lower()  #小寫

‘de8ug‘

name.capitalize() #首字母大寫

‘De8ug‘

name = "python is cool"

name.title()  #標題大寫

‘Python Is Cool‘

name.strip(‘python‘) #去掉python（開頭和結尾的空格或者字串去掉）

‘ is cool‘

email = ‘de8ug#foxmail.com‘

email.replace(‘#‘,‘@‘)    #email.replace(old,new)

‘[email protected]‘

email.split(‘#‘)        #去除分隔字元，變成列表

[‘de8ug‘, ‘foxmail.com‘]

email.zfill(30)

‘0000000000000de8ug#foxmail.com‘

email.ljust(30,‘8‘)   #email.ljust(width.fillchar)  靠左對齊再填充

‘de8ug#foxmail.com8888888888888‘

email.rjust(20,‘*‘)   #靠右對齊再填充

‘***de8ug#foxmail.com‘

email.center(20,‘*‘)   #中間對齊再填充

‘*de8ug#foxmail.com**‘

字串查

1.字串.方法（）

‘de8ug‘.count(‘8‘)

1

name.isupper()  #判斷是否為大寫

False

name.islower()  #判斷是否為小寫

True

py = ‘python is cool‘

py.index(‘is‘)   #查詢在哪個位置

7

py.index(‘o‘)

4

py.find(‘is‘)

7

py.find(‘isaaa‘)   #所有不存在為-1

-1

dir(py)  #看有哪些方法可用

[‘__add__‘, ‘__class__‘, ‘__contains__‘, ‘__delattr__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__getitem__‘, ‘__getnewargs__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__init_subclass__‘, ‘__iter__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__mod__‘, ‘__mul__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__rmod__‘, ‘__rmul__‘, ‘__setattr__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘capitalize‘, ‘casefold‘, ‘center‘, ‘count‘, ‘encode‘, ‘endswith‘, ‘expandtabs‘, ‘find‘, ‘format‘, ‘format_map‘, ‘index‘, ‘isalnum‘, ‘isalpha‘, ‘isdecimal‘, ‘isdigit‘, ‘isidentifier‘, ‘islower‘, ‘isnumeric‘, ‘isprintable‘, ‘isspace‘, ‘istitle‘, ‘isupper‘, ‘join‘, ‘ljust‘, ‘lower‘, ‘lstrip‘, ‘maketrans‘, ‘partition‘, ‘replace‘, ‘rfind‘, ‘rindex‘, ‘rjust‘, ‘rpartition‘, ‘rsplit‘, ‘rstrip‘, ‘split‘, ‘splitlines‘, ‘startswith‘, ‘strip‘, ‘swapcase‘, ‘title‘, ‘translate‘, ‘upper‘, ‘zfill‘]

my_name =input(‘name: ‘)

name: de8ug  

my_name

‘de8ug  ‘

len(my_name)   #可以包含空格

7

type(my_name)

str

my_name.strip()

‘de8ug‘

len(my_name.strip())

5

2. 切片查詢

py = ‘python2 python3 python4 python8‘

py[3]

‘h‘

py[-2]

‘n‘

py[:6]

‘python‘

py.index(‘2‘)

6

py[:py.index(‘2‘)]

‘python‘

something = ‘abcdefg1234567‘

something[1:6:2]   #索引1到6 步長為2

‘bdf‘

something[4:]  #左邊包括

‘efg1234567‘

something[:4]  #右邊不包括

‘abcd‘

something[4::4]

‘e26‘

something[something.index(‘e‘):]

‘efg1234567‘

email = ‘[email protected]‘

email.split(‘@‘)   #去除分隔字元，變成列表

[‘de8ug‘, ‘foxmail.com‘]

email.index(‘@‘)

5

email[:email.index(‘@‘)]

‘de8ug‘

email.find(‘@‘)

5

email[email.find(‘@‘)+1:]   #左邊包括

‘foxmail.com‘

python字串的增刪改查