Python Learning essay (i)

first, String Learning

1 # Create a String method 2 ' ABC ' 3 # or 4 str1 = str ('abc)

1 # string First letter lowercase to uppercase, original uppercase unchanged 2 2 str2 = str1.captilize ()3print(str2)--   ABC

1 # capitalize the first letter of the string into lowercase, lowercase 2 ' ABC ' 3 str2 = str1.casefold ()4print(str2)---  ABC

 1  #   In the string drama, the first argument is to set the string width, the second parameter is the padding character on both sides, and the default is a space  2  str1 = str ("  abc   " )  3  str2 = str1.center (20, '  

 1  #   Counts the number of characters in a string, the first argument is a character, the second, the third argument is the start and end index  2  str1 = str ("  abcdgellsllxosngsewwlfalnaaan   '  

 1  #   Change the string to another encoding format, the parameter is the format you want to encode  2  str1 = str ( "  abcdgellsllxosngsewwlfalnaaan   " Span style= "color: #000000" >)  3  str2 = Str1.encode ("  utf-8   " "  4  print  (str2)-- > B " abcdgellsllxosngsewwlfalnaaan " Span style= "color: #800000" " 

 1  #   Reads whether the payment string ends with a character, The first argument is a character, the second, the third argument is the starting index, and returns a Boolean value that does not write the two or three parameter  2  str1 = str ( " abcdgellsllxosngsewwlfalnaaan  "  )  3  result = Str1.endswith ( '  l   ", 5,25 4  print  (result)--False 

 1  #   Converts the ' \ t ' character in a string to a space, the parameter is the space character width to convert, and does not set the default to 8  2  str1 = str ("  abcdgellsllx\tosngsewwlfalnaaan   " )  3  str2 = str1.expandtabs (10"  4  print  (str2)-- > Abcdgellsllx Osngsewwlfalnaaan 

 1  #   Finds the position of a character in a string from left to right, returns the index position, does not return 1, The first argument is a character, and the second and third argument is the starting index  2  str1 = str ( Span style= "color: #800000" > " abcdgellsllxosngsewwlfalnaaan   " )  3  result = Str1.find ( '  s   " )  4  print  (result)-8 

 1  #   Format the string, corresponding to the formatted string by location  2  str1 = str ( " Span style= "color: #800000" >zhushanwei {0} {1}   " )  3  str2 = Str1.format ("  is   ",  " handsome   " )  4  print  (str2)-zhushanwei is  handsome 

 1  #   Find the index of a character in a string, return it, the argument is a character  2  str1 =  "  lasgiongfa457af   " 3  result = Str1.index ("  4   " )  4  print  (result)---

# determines whether a string consists of numbers or letters, returns a Boolean value ' LASGIONGFA457AF '  = str1.isalnum ()print(result)---  True

1 # determines whether a string is composed of letters, returns a Boolean value 2 ' LASGIONGFA457AF ' 3 result = str1.isalpha ()4print(result)  -->false

# determines whether a string is a decimal number, returns a Boolean value ' 4575 '  = str1.isdecimal ()print(result)---   True

# determines whether a string is an integer, returns a Boolean value ' 4575 '  = str1.isdigit ()print(result)---   True

1 # returns a Boolean value that determines whether a string is a valid character, such as a variable that cannot begin with a character such as a number, @, etc. 2 ' 4575 ' 3 result = str1.isidentifier ()4print(result)---   False

# determines whether the string is lowercase and returns a Boolean value ' Abcnon '  = str1.islower ()print(result)----  False

Python Learning essay (i)