iterate list python

Three ways to iterate through the list of numbers and values: Recently learn the language of Python, feel its work efficiency has a great improvement, special on Valentine's Day wrote this blog, the following nonsense say, direct sticker code #!/usr/bin/env python#-*-coding:utf-8-*-if __name__ = = ' __main__ ':

can also use a two-layer loop to generate a full array:>>> [m + n for m in ‘ABC‘ for n in ‘XYZ‘][‘AX‘, ‘AY‘, ‘AZ‘, ‘BX‘, ‘BY‘, ‘BZ‘, ‘CX‘, ‘CY‘, ‘CZ‘]Three-and three-storey loops are rarely used.Using a list-generated formula, you can write very concise code. For example, listing all the file and directory names in the current directory can be implemented in one line of code:>>> import os # Import OS module, the concept of module is >>> [d for d in O

EXP1 is true when executing code CODE1, if not true, Judge Exp2, if EXP2 is true, execute code2, and so on, if all is not true, execute code.Score=85if 90: print (' A ') elif 80: print (' B ') elif 70: print (' C ') elif 60: Print (' D ') Else: print (' E ') #由于score = 85, so 80 2. Functionsdef func_name ([param]): Function code GroupWhere Func_name is the function name, we can customize, Param is passed to the function of the formal parameter, can not give,

Recently, bloggers want to use Python to remove repetitive or similar SQL when analyzing database slow query logs, so you don't have to look at a lot of similar SQL. Repeating the same data is simpler and can be done using the built-in set command. For example: L1 = [' A ', ' B ', ' C ', ' d ', ' e ', ' A ', ' B ', ' F ']L2 = List (set (L1))Print L2 This is easy to implement with

List of lists:1 #Li = [one, one, one, one, and one]2 #Parameters3 #1. The original value was last appended4 #object. Method (..) # Li Object calls the Append method5 #li.append (5)6 #Li.append ("Alex")7 #li.append ([1234,2323])8 #Print (LI)9 #2 emptying the listTen #li.clear () One #Print (LI) A - #3 Copy, shallow copy - #v = li.copy () the #Print (v) - #4. Count the number of occurrences of an element - #v = li.count (a) - #Print (v) + - ## 5. Expa

Python is a lovely and interesting dynamic language, powerful and efficient, the syntax is beautiful and simple, let's play the lovely side of it: List resolution and generator expressions. List resolution: Syntax: [Expr for Iter_var in iterable] or [expr for Iter_var in iterable if COND_EXPR] Description The first syntax: first

The list generation, which is the comprehensions, is a very simple and powerful build of Python built-in that can be used to create lists.For example, to generate a list, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] you can use range(1, 11) :>>> range(1, 11)[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]But what if you want to build [1x1, 2x2, 3x3, ..., 10x10] ? Method One is the loop:>>> L

Using a For loop to traverse list and tuple, this traversal becomes an iterativeIn the C language is the subscript to get the value, for...in this way is actually the same.In the section of the function, this says---> ' Sum function sum (), sum (Iterable,start), the first parameter must be an object that can be iterated, listtuple. ' Iterative objects are list,tupleSo when using for traversal, the object is

moves back several bits, until two lists from the tail count to the length of the Traverse pointer are the sameThe next step is to iterate over each bit to compare whether it is equalSo without opening up new space time is traversing O (n) over and over1 classsolution (object):2 defGetintersectionnode (self, Heada, headb):3 """4 : Type Head1, Head1:listnode5 : Rtype:listnode6 """7 #set up a hash table to store each element

ListsPython's designers have a lot of options when implementing the data structure of the list. Each choice has the potential to affect how quickly the list operation executes. Of course they also try to optimize some of the less common operations. But when it comes to tradeoffs, they sacrifice the performance of infrequently used operations to fulfill common functions.This article address: http://www.cnblo

Create List subject = ["Liunx", "Python", "web", "Java"]#读取列表print (subject) #打印显示 [' Liunx ', ' python ', ' web ', ' Java '] #列表的切片, the slice index is the 0-based print (subject[0]) # NO. 0 index, That is, the first element of the list print (subject[1]) print (subject[2]) print (subject[3]) print (Subject[1:3]) # re

Python List When I introduce the Python tuple, I use the analogy method, compare it to a bag, you can store different things in the bag. The Python list is very similar to this, so its function is very similar to the function of the bag. One thing is different, though, is t

processed on the list so that they cannot be modifiedYou can also include anything within a tuple.3.1 You can get a special value within a tuple by index3.2 You can get special values within tuples by slicing them3.3 Strings, lists, and tuples can be converted to each other3.4 can be used for loops and can also iterate over objects3.5 tuples are also orderly.##########################Tuple methods: Count a

to reverse the list.Xx.sort ()Xx.reverse ()Meta-groupA python tuple is similar to a list, except that the elements of a tuple cannot be modified . tuples use parentheses, and the list uses square brackets. Dictionary key key valueNote that in the dictionary operation, the dictionary is judged by the keymodifying elementsThe data in each element of the dictionary

First, if you want to use the Python module, you can use the Import module name directly, if you want to use a third-party module, please download the installation (PIP installation) yourself.Second, list:Define a list of empty lists: List = []Add an element to the list aa:list.append (' AA ') = = "Print (

source code manually using the C compiler.The compiled source code, with more selectivity in functionality, provides more flexibility for Python installation.Here's how to install Python on different platforms: 1.Unix Linux Platform Installation Python Here are the simple steps to install Python on UNIX Linux platfo

1. Create a list1) The different data items separated by commas are enclosed in square brackets, and the data types of the elements in the list can be inconsistent. The list index starts at 0. Lists can be intercepted, combined, and so on.1List1 = ['Physics','Chemistry', 1997, 2000]2List2 = [1, 2, 3, 4, 5 ]3LIST3 = ["a","b","C","D"]4List4=[]#Create an empty list2. Accessing

The list-generation, comprehensions, is a very simple, powerful build that Python can use to create a list. For example, to generate list [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] You can use range (1, 11): >>> Range (1, one) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] But what if you want to generate [1x1, 2x2, 3x3, ..., 10

A set of ordered items the variable data type "can be added to the list" can contain any data type or another list "can be any combination nested" list is a collection of data surrounded by square brackets "[]", different members with "," delimited list can access members by ordinal Defined >>> L = [] #空列表 >>> L = [1,2

(starting from 0 to take 2, omitting 0 for starting from the first, omitting the last for direct fetch to the last one)A[0:4:2] for ad (starting from 0, take 4th, step 2)Lists [], mutable types of data structures that can be added to delete and change values in the list, can iterate over theList1=[' A ', 1, (1,), [' Hello ', ' world ']LIST1[1] is 1List1.append (' 123 ') appends an object to a listList1.ins