Priority grasp
1, int int
Uses: general definitions for integer, such as age, phone number, etc.
Defined manner: age = 18 i.e., age = int (18)
Commonly used mathematical calculation
Int can be used to convert between hexadecimal: print (int ( '110', 2))
print(int('123', 8))
print(int('801', 16))
Type Summary: int is disordered, immutable type can store a value.
2, float type
Use: the recording decimals, height, weight, etc.
Defined method: height = 1.80 i.e., height = float (1.80)
For mathematical calculations
A summary: float is disordered, immutable, you can store a value
3, strings
Usage: used to store descriptive information, name, etc.
Defined method: s = '' s = '' '' s = '' '' '' s = '' '' '' '' '' '' quoting no difference, but can not mix added: string before adding r escape the special meaning of the symbol into a string
Common methods: 1, the index value (forward can also be reverse, not only take deposit)
= S1 ' Hello World ' Print (S1 [. 4]) # forward taken o Print (S1 [-7]) # reverse takes o
2, slice index: intercepting a short string string
= S1 ' Hello World ' Print (S1 [2:. 5]) # take LLO Print (S1 [. 4:]) # fetch World O Print (S1 [:. 5]) # fetch Hello Print (S1 [0: -2: 2]) # setting step 2, taken hlowr Print (S1 [:: -1]) # reversed string dlrow olleh
3, members of the operation: in, not in returns a Boolean value
4, strip: removing the left and right sides of the character string or symbol space
INPUT = name ( ' Enter name ' ) .strip () Print (name) A1 = ' *** *** LZN ' Print (a1.strip ( ' * ' ))
5, split: segmentation, segmentation of the string can be specified sliced separator (space by default) returns a list of
a1 = 'lzn*25*male' print(a1.split('*')) # ['lzn', '25', 'male']
6, the length len: Get the current string length, i.e. the number of characters
print (referred to as ( "Hello"))
>>> 5
7, the cycle for: each one removed character string
s = 'hello world' for i in s: print(i)
Need to know
8, restrip \ lstrip: removal of the right spaces \ resection left blank
9, lower \ upper: case conversion
str.lower () will all become English string lowercase
str.upper () will string all uppercase English
10, startswith \ endswith: determine what the current string begins, returns a Boolean value
11, formatted output format: {} pass the index value may also be specified by value
Print ( ' My name is {}, {} years old this year ' .format ( ' LZN ' , 25 )) # >>> My name lzn, 25 years old this year Print ( ' My name is {0}, {1} years old this year ' . format ( ' LZN ' , 25 )) # >>> my name lzn, 25 years old this year Print ( ' my name is {1}, {0} years old this year ' .format ( ' LZN ' , 25 )) # >>> me called 25 years old this year lzn
12, split \ rsplit: \ from right to left in order to be segmented in accordance with the character string from left to right, and can specify the number of cuts separator.
str = 'lzn*25*male' print(str.rsplit('*', 1)) >>> ['lzn*25', 'male']
13, jion: each element can be spliced to the specified object separator iterations, the result is a string of splicing
l1 = ['lzn', '25', 'male'] print('|'.join(l1)) >>>lzn|25|male
14, replace: the replacement string elements
Syntax: replace ( 'Oldest', 'new content')
str = 'lzn,18' print(str.replace('lzn', 'Bill')) >>>'Bill,18'
15, isdigit: determining whether a string of numbers is a pure, returns a Boolean value
num = '1233211234567' print(num.isdigit()) >>>True
Learn operation
16, find: find the location (range can be specified) of an element in the current string, returns the index, not found -1
17, index: with the find, can not find abnormal returns
18, count: count the number of an element of the current string
19, center \ ljust \ rjust \ zfill: setting the total width, centered \ Left \ right justified \ right alignment, the width of the string with filled symbols not specified, zfill filled with 0
20, is series
A summary of the string: ordered, immutable, you can store a value
4. List
Uses: for storing the value of one or more different types of
Defined by:, separated by a comma between each value by [] stored value
1, the index value (can be positive and negative), it may be desirable to deposit
l1 = [1,2,3,4,5]
print(l1[2])
>>>3
2, the index sliced
print(l1[1: 4])
>>>[2,3,4]]
3, add
3.1 append (): added value, can only be added to the last one, you can only add a value
l1.append(1000)
print(l1)
>>>[1,2,3,4,5,1000]
3.2 insert (): the value is inserted, the insertion position specified by the index
l1.insert(3, 999)
print(l1)
>>>[1,2,3,999,4,5]
3.3 extend (): a plurality of values can be increased (the object must be iterative)
l1.extend([6,7,8])
print(l1)
[1,2,3,4,5,6,7,8,9]
4, delete
4.1 remove (): delete the specified value (the first value to delete only appear)
l1.remove(1)
print(l1)
>>>[2,3,4,5]
4.2 pop (): do not pass a default value beginning from the last delete, delete the value of the return value
l1.pop() l1.pop(2)
print(l1) print(l1)
>>>[1,2,3,4] >>>[1,2,4,5]