String Common operations
7 Month Day, 7 Month Day , 7 Month Day, 7 Month Day, 8 Month Day, 2 Month Day
Initial capital: A_str.capitalize ()
Number of statistics strings: A_str.count ("x")
Output character, not enough to fill with the specified character, the center of the character: A_str.center (50, "-")
Determine what the string ends with: A_str.endwith ("XX")
Converts the tab in a string to a specified number of spaces: A_str.expandtabs (tabsize=30)
Finds the position of the specified string in the string: A_str.find ("XX")
The string can also be sliced: A_str[a_str.find ("XX"):]
Formatted output: A_str.format (xx= "x", xxx= "xxx")
Dictionary format output: a_str.format_map ({' name ': ' Alex ', ' Year ': 12})
Determine if it is an Arabic numeral (all English characters +0-9): A_str.isalnum ()
Determine if it is an English character: A_str.isalpha ()
Determine whether it is a decimal number: A_str.isdecimal ()???
Determine whether it is an integer: A_str.isdigit ()
Determine if the identifier is valid (valid variable name): A_str.isidentifier ()
To determine if it is lowercase: a_str.islower ()
Determine if there are only numbers (no decimal points): A_str.isnumeric (), test: "0132". IsNumeric ()
Determine if it is a space: A_str.ispace ()
Determine if the first letter of each word is capitalized: A_str.istitle ()
Determine if it can be printed: a_str.isprintable () #tty file, drive file
To determine if uppercase: A_str.isupper ()
Combines a string list into a string, separated by the specified character: "Specified character". Join (A_str_list)
Outputs a string of the specified length, the string on the left, and insufficient when the specified character (string? ) padding: a_str.ljust (50, ' * ')
Outputs a string of the specified length, the string on the right, and the specified character when insufficient (string? ) padding: a_str.rjust (50, ' * ')
Character lowercase: a_str.lower ()
Character capitalization: A_str.upper ()
Remove the left space carriage return: "Test". Lstrip ()
Remove the right space carriage return: "Test". Rstrip ()
Remove the space on both sides to enter: ' test\n '. Strip () \ r will be?
Converts the specified letter to the corresponding number:
P=str.maketrans ("abcdef", "123456")
Print ("Alex Li". Translate (p))
Replacement string: A_str.replace (' l ', ' l ', 1)
Find character position in string from right to left: A_str.rfind (' x ')
Separates a string into a list by a specified character, without specifying a space: A_str.split ()
Separate strings by carriage return as a list: A_str.splitlines () (\r,\n?). )
Case conversion: A_str.swapcase ()
Fill in 0 of the string with insufficient parts: A_str.zfill (50)
Dictionary
7.18,7.19,7.21,7.28,8.28,2.28
Key-value
JSON format
Unordered, key is unique, the first example has a curly brace at the end
Value, Info[key],info.get (key)
Determine if key exists, key in Info,python2:info.haskey (key)
Multi-level dictionary nesting, modification, primary level positioning, assignment
Key do not use Chinese
Print all Values,keys,setdefault (), first determine if there is??? , does not exist then creates
Info.update (Info2), merge two dictionaries, key consistent when overwriting old values with new values???
Convert to list, info. Items ()
Fromkeys (alist,value) Create a new dictionary, each value in the list is only key???
Output Key,value:
For key in info:
Print (I,info[i])--efficient
For k,v in Info.items ():
Print (K,V)--low efficiency, first converted to list after output
Level Three Menu instance
Flow chart
Building a dictionary
Cycle
Pass:nothing, I don't mean to do anything.
Homework:
Shopping cart optimization, divided into sellers and buyers two documents
Buyer: The product information exists in the file, each run shows the purchased goods and balances
Sellers: Can add items, modify prices
Python Learning Note Five: string common operations, dictionaries, three-level menu instances