Common operations for "code learning" python strings

One, the string operator

The following table instance variable a value is the string "Hello" and the B variable value is "Python":

operator	Description	Example
+	String connection	>>>a + b 'hellopython'
*	Repeating output string	>>>a * 2 'hellohello'
[]	Getting characters in a string by index	>>>a[1] 'e'
[:]	intercept part of a string	>>>a [1:4] ' ell
in	member operator-if the string contains the given character returned True	>>> "h " in a True
not in	member Operators- Returns True if the string does not contain the given character	>>> "m" not in a true
R/r	Raw string-Raw string: all strings are used directly as literal meanings, without escaping special or non-printable characters. The original string has almost exactly the same syntax as a normal string, except that the first quotation mark of the string is preceded by the letter "R" (which can be case).	>>>print r \ n ' \n >>> print r'\ n ' \n

Code:

1A ="Hello"2b ="Python"3 4 Print "A + b output results:", A +b5 Print "A * 2 output results:", A * 26 Print "a[1] Output results:", a[1] 7 Print "A[1:4] Output results:", A[1:4] 8 9 if("H" incha):Ten     Print "H in variable a"  One Else : A     Print "H is not in variable a"  -  - if("M"  not incha): the     Print "M not in variable a"  - Else : -     Print "M in variable a" -  + PrintR'\ n' - PrintR'\ n'

The results of the program execution are:

1 2 A + b output Result: Hellopython  3 A * 2 output result: Hellohello  4 a[1] Output: E
   
     5 a[1:4
    ] Output result: Ell 
     6
    H in variable a 
    7
    M is not in variable a 
    8
    \n
      9\ n
   

Second, Python string formatting

Python supports the output of formatted strings. Although this may use a very complex expression, the most basic usage is to insert a value into a string that has the string format of%s.

Code:

Print " My name is%s and weight is%d kg! " % ('Zara'

Run results

My name is Zara and weight are kg!

Third, Python string built-in function

If there is a string mystr = "Hello World sqyy"

1. Find

Detects if STR is included in MyStr, or returns 1 if the index value is returned.

Mystr.find (str, start=0, End=len (mystr))

2. Index

Just like the Find () method, only if STR does not report an exception in MyStr.

3. Count

Returns the number of times that STR appears in the mystr between start and end

Mystr.count (str, start=0, End=len (mystr))

4. Replace

Replace the str1 in mystr with the STR2 if count specifies that the replacement is not more than count times.

Mystr.replace (str1, str2,  Mystr.count (STR1))

5. Split

Cut, with Str as a delimiter slice mystr, if Maxsplit has a specified value, only maxsplit substrings are delimited

Mystr.split (str="", 2)    

6, Capitalize

Capitalize the first character of a string

Mystr.capitalize ()

7, StartsWith

Checks whether the string starts with obj, or returns True, otherwise False

Mystr.startswith (obj)

8, EndsWith

Checks whether the string ends with obj, or returns False if True.

Mystr.endswith (obj)

9, lower

Convert all uppercase characters in mystr to lowercase

Mystr.lower ()   

10, Upper

Convert lowercase letters in mystr to uppercase

Mystr.upper ()

11, Ljust

Returns the left alignment of an original string and fills the new string with the width of length with a space

12, Rjust

Returns the right alignment of the original string and fills the new string with the width of the length with a space

Mystr.rjust (width)    

13. Center

Returns the center of the original string and fills the new string with a space of length width

Mystr.center (width)  

14, Lstrip

Delete the left mystr space

Mystr.lstrip ()

15, Rstrip

Remove spaces at the end of a mystr string

Mystr.rstrip ()   

16, RFind

Similar to the Find () function, it is just looking from the right.

Mystr.rfind (str, Start=0,end=len (MYSTR))

17, Rindex

Similar to index (), but starting from the right.

Mystr.rindex (str, Start=0,end=len (MYSTR))

18, partition

The mystr is divided into three parts, str, str and STR

Mystr.partition (str)

19, Rpartition

Similar to the partition () function, but starts from the right.

Mystr.rpartition (str)

20, Splitlines

Returns a list containing rows as elements, separated by rows

Mystr.splitlines ()  

21, Isalnum

Returns True if all mystr characters are letters or numbers, otherwise False

Mystr.isalnum ()  

22, Isalpha

Returns True if mystr all characters are letters, otherwise False

23, IsDigit

Returns True if the mystr contains only a number, otherwise False.

24, Isspace

Returns True if the mystr contains only spaces, otherwise False is returned.

Mystr.isspace ()   

25, Isupper

Returns True if all characters in the mystr are uppercase, otherwise False

Mystr.isupper ()  

26. Join

Insert Str after each character in the mystr to construct a new string

1 mystr.join (str)

Common operations for "code learning" python strings