python variable type - usage of python string str() (example)

In this article, I will talk about the python string str() in the standard numeric type in python. I hope it can help you who have just come into contact with python.

python string (String)：

Python string is a string of characters composed of numbers, letters, and underscores. It can generally be recorded as follows:

s="a1a2···an"(n>=0)

(String is a data type that represents text in programming languages)

Python strings have two order of values:

1. From left to The right index starts from 0 by default, and the maximum range is 1 less than the string length.

2. The right-to-left index starts with -1 by default, and the maximum range is the beginning of the string.

If you want to take a section of string from a string, you can use [head subscript: tail subscript] to intercept the desired string, where the head subscript is calculated from 0. It can be a positive or negative number. If the tail subscript is empty, it means the head and tail are obtained. ([Head subscript: Tail subscript] The intercepted string includes the characters in the table below the head, but does not include the characters in the tail subscript. The character before the number written in the tail subscript is taken.) It is possible to just say it An unconvincing example is as follows:

#!/usr/bin/python
# -*- coding: UTF-8 -*-

s = '1458592158'
print s[2:6]

The output result of the above example is:

5859

When using colon-separated strings, python returns a new object, and the result contains the following For contiguous content marked by an offset, the left edge is inclusive of the lower border.

The above result contains the value b of s[1], and the maximum range obtained does not include the tail subscript, which is the value f of s[5].

The plus sign ( ) is the string concatenation operator, and the asterisk (*) is the repeating operation . The following example:

#!/usr/bin/python
# -*- coding: UTF-8 -*-
 
str = 'Hello World!'
 
print str           # 输出完整字符串
print str[0]        # 输出字符串中的第一个字符
print str[2:5]      # 输出字符串中第三个至第五个之间的字符串
print str[2:]       # 输出从第三个字符开始的字符串
print str * 2       # 输出字符串两次
print str + "TEST"  # 输出连接的字符串

The results of the above example are as follows:

Hello World!
H
llo
llo World!
Hello World!Hello World!
Hello World!TEST

The above content is some examples and applications of python strings. I hope to provide some help to friends who have just come into contact with python.

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