Home > Article > Backend Development > Detailed explanation of three methods of string concatenation in Python and their efficiency and applicable scenarios
This article mainly introduces the three methods of string connection in Python, their efficiency, and detailed explanations of applicable scenarios. It has certain reference value and interested friends can refer to it.
There are generally three ways to connect Python strings:
Method 1: Connect directly through the plus (+) operator
website = 'python' + 'tab' + '.com'
Method 2: join method
listStr = ['python', 'tab', '.com'] website = ''.join(listStr)
Method 3: Replace
website = '%s%s%s' % ('python', 'tab', '.com')
Let’s talk about three more methods The difference
Method 1 is simple and direct to use, but many people on the Internet say that this method is inefficient
The reason why using + for string concatenation in python is inefficient , because strings in python are immutable types. When using + to connect two strings, a new string will be generated. To generate a new string, you need to apply for memory again. When there are many strings that are continuously added ( a+b+c+d+e+f+...), low efficiency is inevitable
Method 2 is slightly complicated to use, but it is efficient when connecting multiple characters, and it will only happen once Memory application. And if you are connecting characters in a list, this method must be the first choice
Method 3: String formatting, this method is very commonly used, and I also recommend this method
The following experiments are used to illustrate the efficiency of string concatenation.
Comparison object: plus connection VS join connection
Python version: python2.7
System environment: CentOS
Experiment 1:
# -*- coding: utf-8 -*- from time import time def method1(): t = time() for i in xrange(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' print time() - t def method2(): t = time() for i in xrange(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() -t method1() method2()
Result:
0.641695976257
0.341440916061
Experiment 2:
##
# -*- coding: utf-8 -*- from time import time def method1(): t = time() for i in xrange(100000): s = 'pythontab'+'pythontab'+'pythontab'+'pythontab' print time() - t def method2(): t = time() for i in xrange(100000): s = ''.join(['pythontab','pythontab','pythontab','pythontab']) print time() -t method1() method2()