A numerical conversion of the number and type of
. 1, int string can be converted into digital integer containing pure
2, binary conversion
# Turn into other binary decimal
# Print (bin (12 is)) # 0b1100 # Print (OCT (12 is)) = # 12 is 0o14>. 1 * (. 8 **. 1) 2 + (0. 8 **) # Print (hex (12 is)) 0xc # # The output '' ' 0b1100 0o14 0xc ' ''
# Binary conversion (Learn **)
# hexadecimal to decimal other
print (int ( '10', 2)) # 2 binary transfer
print (int ( '10', 8)) # 8 hexadecimal revolutions
print ( int ( '10', 16) ) # 16 revolutions hexadecimal
3, the variable type immutable type
Variable Type: if the value changes, id unchanged, indicating that you change the original value
# immutable: when the value is changed, id must variant
# Python variables can be divided into two types
# immutable type ( Digital , a string, a tuple , not variable set)
# variable type ( list, dictionaries , set variable)
Second, the use of string conversion
1, according to the index value (Forward + Reverse take take): can take only (non-modified)
2, a slice (care regardless of the end, step): the interception of a new small strings from a larger string
# The left head is fixed, the right place is not fixed according to figures to say the beginning and end points
Example:
= S ' Hello ' Print (S [0:. 5 ]) Print (S [0: 10: 2]) # step representing every few take one step is not written by default. 1 Print (S [-1 ]) Print (S [. 5: 0: -1]) # slice is from left to right default values, negative values understand Print (S [-1: -1: -10 ]) # output '' ' Hello HLO O Olle olleh '' '
. 3, len (length):
Statistics is the number of characters in the string
S1 = 'Hello'
Print (len (S1)). 5 #
4, in and not in (membership operator):
Determining whether there is a substring of string in a large
5、strip
Removing the string of characters on both sides of the left and right, regardless of the intermediate
using the built-in method using a unified symbol period (.)
Strip () Default space removal string end to end,
. 6, split (splitting)
for a certain string according to the tissue separator, it can be cut into split list, and further the value for
# emphasized: split out segmentation data type is a list
# if not specified, the split and the effect is the same rsplit
data = 'jason|123| handsome' print(data.split('|')) username,password,info = data.split('|') print(username,password,info)
#输出结果
#['jason', '123', ' handsome']
#jason 123 handsome
7. .lower () all lowercase string
All .upper () String uppercase
8, startswith, endswith: determine what the beginning and ending
. 9, the format of the three kinds of games are played
first, by location stations (% s principle and has been)
Example:. Str1 = 'my name is {} my age is {}' format (18, 'jason',)
a second species, according to the index placeholder
Example:. str1 = 'my {1 } name is {0} my {0} age is {0}' format ( 'egon', 18)
a third, by name Road name placeholder ( keyword-parameters)
Example:. str1 = 'my {name } name is {age} my {name} age is {name}' format (name = 'jason', age = 18)
10, join: the plurality of types of splice elements of the container into a specified character string from
Example:
= RES [ ' Jason ' , ' 123 ' , ' Handsome ' ] STR = ' $ ' .join (RES) Print (STR) # output # Jason $ 123 $ Handsome
11, replace the replacement characters in the string (optional number)
Example:
str = 'egon is dsb and egon is sb he has a BENZ' res = str.replace('egon','kevin',1) #输出结果 # kevin is dsb and egon is sb he has a BENZ
12, isdigit # determines whether a string contains purely digital
13、find、rfind、index、rindex、count
= S ' Kevin Kevin IS and O IS DSB SB ' Print (s.find ( ' DSB ' )) # returns the index where the d-characters Print (s.find ( ' XXX ' )) # can not find the time no error returns -1 Print (s.find ( ' I ' , 0,3)) # can also be limited by the look index Print (s.index ( ' O ' )) # index character where the return pass value Print (s.index ( ' i ' , 0,5)) # returns the index where the preaching character, if no will complain Print (s.count (' N- ' )) # number of characters that appear in statistic # output '' ' . 9 -1 -1 13 is . 3 . 3 ' ''
14, center (middle), ljust, rjust, zfill (supplemented with 0) Usage
= s9 ' tom ' print (s9.center (12, ' * ' )) print (s9.ljust (6, ' $ ' )) print (s9.rjust (6, ' $ ' )) print (s9.rjust ( 6, ' ' )) print (s9.zfill (6 )) # 输出结果 '' ' **** ***** tom tom $$$ $$$ tom tom 000tom ' ''
16, expandtabs few more Tab key
= S10 ' A \ TBC ' Print (s10.expandtabs (10 )) # output # A BC
15, captalize (first letter capitalized), swapcase (invert case), title (the first letter of each word capitalized)
= S12 ' HELLO WORLD SH10 ' Print (s12.capitalize ()) # the Hello world capitalized Print (s12.swapcase ()) # invert case Print (s12.title ()) # the first letter of each word in the size # output '' ' the Hello World SH10 HELLO WORLD SH10 the Hello World SH10 ' ''
16, is a digital series
'' .isnumeric (): unicode, Chinese figures, insofar as it represents the Roman numeral numbers are identified.
'' .isdecimal (): unicode recognizes only ordinary Arabic numerals.
'' .isdigit (): bytes, using the unicode isdigit usually has to meet the needs of