String related operations:
+ :string1+string2 #Connect strings, link the next string to the back of the previous string
* :string*n #Create a new string and repeat the original string n times
[] :string[n] #Get a character at the corresponding position from the string
[:] :string[n:m] #Intercept the string, if it is: m from beginning to m, if it is n: from n to end
in :char in string #Judge whether a character is in the string, if it returns true (True)
not in :char not in string #Judge whether a character is not in the string, if it returns true (True)
r/R : r/Rstring #The actual meaning of escaped characters is prohibited, the entire character is the original meaning
Conversion of character case in the string:
* S.lower() #Lowercase
* S.upper( ) #Capital
* S.swapcase() #Case swap
* S.capitalize() #Capitalize the first letter
* String.capwords(S) #This is a method in the module. It separates S using the split() function, then uses capitalize() to change the first letter to uppercase, and finally uses join() to merge it together
* S.title() #Only the first letter is uppercase, and the rest are lowercase, which is not available in the module This method
aligns the string when outputting:
* S.ljust(width,[fillchar]) #Output width characters, S is left-aligned, and the missing part is filled with fillchar. The default is spaces.
* S.rjust(width,[fillchar]) #Align right
* S.center(width, [fillchar]) #Align center
* S.zfill(width) #Change S to width and align to the right , fill the missing part with 0
Search and replace in the string:
* S.find(substr, [start, [end]]) #Return the label of the first letter of substr appearing in S, if If there is no substr, -1 is returned. The function of start and end is equivalent to searching in S[start:end]
* S.index(substr, [start, [end]]) #Same as find(), except that when there is no substr in S, one will be returned Runtime error
* S.rfind(substr, [start, [end]]) #Returns the label of the first letter of the substr that last appeared in S. If there is no substr in S, it returns -1, that is, from the right The first letter number of substr that appears for the first time
* S.rindex(substr, [start, [end]])
* S.count(substr, [start, [end]]) #Calculate substr in S The number of occurrences in
* S.replace(oldstr, newstr, [count]) #Replace oldstar in S with newstr, and count is the number of replacements. This is the general form of replacement. There are also some functions to replace special characters
* S.strip([chars]) #Remove all the characters in the chars before and after S. It can be understood as replacing the chars before and after S with None
* S.lstrip([chars])
* S.rstrip([chars])
* S.expandtabs([tabsize]) #Replace the tab characters in S without spaces, and replace each tab with tabsize spaces, default It is the division and combination of 8
strings:
* S.split([sep, [maxsplit]]) #Use sep as the separator to divide S into a list. maxsplit represents the number of splits. The default separator is a blank character
* S.rsplit([sep, [maxsplit]])
* S.splitlines([keepends]) #Divide S into a list according to the line separator, keepends is a bool value, if If true, line separators will be preserved after each line.
* S.join(seq) #Connect the sequence represented by seq, the string sequence, with S.
String mapping. This function includes two functions:
* String.maketrans(from, to) #Return a translation table composed of 256 characters, in which the characters in from are converted into to in one-to-one correspondence, so from and to must be equal lengths.
* S.translate(table[,deletechars]) #Use the translation table of the above function to translate S and delete some characters in deletechars. It should be noted that if S is a unicode string, the deletechars parameter is not supported, and the same function can be achieved by translating a certain character into None. In addition, you can use the functions of the codecs module to create more powerful translation tables.
Strings also have a pair of encoding and decoding functions:
* S.encode([encoding,[errors]]) #The encoding can have multiple values, such as gb2312 gbk gb18030 bz2 zlib big5 bzse64, etc. are supported. The default value of errors is "strict", which means UnicodeError. Possible values are 'ignore', 'replace', 'xmlcharrefreplace', 'backslashreplace' and all values registered via codecs.register_error. This part involves the codecs module, which is not particularly clear
* S.decode([encoding,[errors]])
The test function of the string, the function returns all bool values:
* S.startwith(prefix[, start[,end]]) #Whether it starts with prefix
* S.endwith(suffix[,start[,end]]) #Ends with suffix
* S.isalnum() #Whether it is all letters and numbers, and has at least A character
* S.isalpha() # Whether it is all letters and at least one character
* S.isdigit() # Whether it is all numbers and at least one character
* S.isspace() # Whether it is all blank characters, and there is at least one character
* S.islower() # Whether the letters in S are all lowercase
* S.isupper() # Whether the letters in S are uppercase
* S.istitle() # Whether S is Capitalized
String type conversion functions, these functions are in the string module:
* string.atoi(s[,base]) #base defaults to 10, if it is 0, then s can be in the form of 012 or 0x23 string, if it is 16, then s can only be a string in the form of 0x23 or 0X12
* string.atol(s[,base]) #Convert to long
* string.atof(s[,base]) #convert to float