Three methods of Python string connection and their efficiency and application scenarios

The Python string connection method, generally has the following three kinds: Method 1: Directly through the plus (+) operator connection website=& 39;python& 39;+& 39;tab& 39;+& 39; com& 39; Method 2

The Python string connection method, generally has the following three kinds:

Method 1: Connect directly via the plus (+) operator

1	website =‘python‘ + ‘tab‘ +‘.com‘

Method 2:join Method

12	listStr =[‘python‘, ‘tab‘, ‘.com‘] website =‘‘.join(listStr)

Method 3: Replace

1	website =‘%s%s%s‘ %(‘python‘, ‘tab‘, ‘.com‘)

Let's take a look at the difference between the three ways.

Method 1, simple and straightforward to use, but many online people say this method is inefficient

The reason why Python uses + for string connections is inefficient because the strings in Python are immutable types, a new string is generated when using + to concatenate two strings, and a new string is required to re-request the memory, when the string of successive additions is many (a+b+c+d+ e+f+ ...) , inefficiency is inevitable.

Method 2 uses a slightly more complex, but high-efficiency connection to multiple characters, with only one memory request. And if the character of the list is connected, this method must be the preferred

Method 3: String formatting, this method is very common, I also recommend the use of this method

The following experiment is used to illustrate the efficiency of string connections.

123	比较对象：加号连接 VS join连接python版本： python2.7系统环境：CentOS

Experiment One:

1234567891011121314

# -*- coding: utf-8 -*-fromtime importtimedefmethod1():    t =time()    fori inxrange(100000):        s =‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘    printtime() -tdefmethod2():    t =time()    fori inxrange(100000):        s =‘‘.join([‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘])    print time() -tmethod1()method2()

Results:

12	0.6416959762570.341440916061

Experiment Two:

1234567891011121314

# -*- coding: utf-8 -*-fromtime import timedefmethod1():    t =time()    fori inxrange(100000):        s =‘pythontab‘+‘pythontab‘+‘pythontab‘+‘pythontab‘    printtime() -tdef method2():    t =time()    fori inxrange(100000):        s =‘‘.join([‘pythontab‘,‘pythontab‘,‘pythontab‘,‘pythontab‘])    printtime() -tmethod1()method2()

Results:

12	0.02656912803650.0522091388702

The above two experiments have completely different results, the only difference between the two experiments is: the number of string connections.

Conclusion: The low-plus connection is inefficient when multiple strings are connected consecutively, and if the number of connections is less, the plus connection efficiency is higher than the join connection efficiency.

Three methods of Python string connection and their efficiency and application scenarios