[Base] python string method summary

A statement

　　0- an ordered sequence of multiple characters;

Second, characteristics

　　1, a string data type is immutable 　　

　　2, the string is ordered

Third, the index

　　Subscript: 'abcde'

　　　　1, from left to right, 0, 1, 2, ...
　　　　2, right to left, the last character index value -1

　　　　The inverse of the index value of the second character-2 ....

　　Slice:
　　　　string [start: stop: step]

　　　　* Start: can take to
　　　　* stop: not take
　　　　　　　care regardless tail
　　　　* start: default from the beginning
　　　　* stop: The default is taken to the end

　　　　N is 1. step
　　　　　　1, cut from left to right, the positive sequence
　　　　　　2, start <stop

　　　　2, step is negative
　　　　　　1, still follow the rules of care regardless of the end of the

　　　　　　2, from right to left cut
　　　　3, start> stop

　　　　　　s = 'abcde'

　　　　　　'abc' --> s[0:3:]

　　　　　　'cba' --> s[2::-1]

　　length

　　　　len (string) # python built-in functions　　

　　解包
　　　　x, y, z = 'abc'　　 # x = 'a' z = 'c'

Fourth, the common method string

　　1. Find

　　　　find () to find, from the left to return the specified character index in the string value
　　　　rfind () to find, starting from the right to return the specified character index value in a string of
　　　　more than two, if can not find the time, or -1

　　　　index () to find, from the left to return the specified character index value in the string
　　　　rindex () to find, starting from the right to return the specified character index value in a string of
　　　　more than two, if can not find the time, error

　　　　count () calculates the number of times specified character string appearing in

　　2. Split
　　　　The splitlines () splits on line breaks, after the split of strings to be placed in a list of
　　　　split (sep, maxsplit)
　　　　　　Function: a character string in accordance with the cut, the remaining portion not cut
　　　　　　sep : who accordance cutting, cutting rules　　　

1 s = 'i love python'
2 s.split(' ') ---> ['i', 'love', 'pyhton']

　　　　maxsplit: the number of cutting; cutting all the default;

　　　　partition (sep)
　　　　　　function: to split the same, but retain the cut part

　　3, replacement
　　　　Replace (Old, new new, COUNT)
　　　　Old: is replaced by a string of
　　　　new: the replacement string
　　　　count: the number of replacements, the default replace all

　　　　translate ()
　　　　　　function: in accordance with the control relationship alternative
　　　　　　parameters: control relationship
　　　　　　　　str.maketrans (character string to be replaced, replace the string)

　　　　　　Where: replaced and replaced with the character of each one correspondence

　　　　　　　　m = str.maketrans ( 'beautiful', 'beautiful')

　　　　　　'Snow really beautiful' .translate (m) -> snow is so beautiful '

　　4, modified
　　　　center center
　　　　ljust Left
　　　　rjust right-aligned
　　　　zfill from the left with 0 fill
　　　　strip to remove leading and trailing spaces, you can also remove the specified character
　　　　lstrip removal left a space, you can also remove the specified character
　　　　rstrip the right to remove spaces, ......

　　5、format

　　　　(1) by filling contents position parameter
　　　　(2) filling the contents of keyword parameter
　　　　(3) is filled with the format
　　　　　　{:} ^ 8 centrally length 8, a space filled with
　　　　　　{: * <10} Left length 10, with a * filling

　　　　(4) accuracy and binary
　　　　　　{: .3f} After three decimal places
　　　　　　{: o} to convert the decimal number to octal
　　　　　　{: x} to convert decimal to hexadecimal
　　　　　　{: b} converts the decimal number binary number　　

　　6, a string formatted

　　　　'% D ...% f ...% s'% (integer data, float data, string data)

　　7, a string deformation
　　　　upper change uppercase
　　　　lower variable lowercase
　　　　swapcase case interchangeable
　　　　title of the first character of each word capitalized
　　　　capitialize the first character of the entire string uppercase
　　　　expandtabs the \ t ---> spaces, a total of eight characters

　　8, the string is determined
　　　　isalnum whether all letters or numbers
　　　　isdigit digital .......... .....
　　　　the isalpha letter ..... ..........
　　　　isupper letter whether the part is capitalized
　　　　islower whether lowercase letters are part
　　　　istitle capitalize the first letter of each word whether
　　　　isspace whether entirely of blank characters
　　　　startswith whether to begin with ....
　　　　whether endswith to end ....

　　9, python two built-in function
　　　　dir () to view the object of all methods
　　　　help () function to use to view, documentation

Third, the escape character

　　Changing the original character meaning: Symbol: \, eg, \ n, \ t, \ b, \ w

　　Original string: r '' to maintain the original character string of the meaning of each character