Simple notes for Python string features and common string methods, python strings

Simple notes for Python string features and common string methods, python strings

Both single quotation marks and double quotation marks can represent strings. The difference lies in escape.

If you are too lazy to add escape characters, you can add r before the string. For example:

print r'C:\some\name'

Do not wrap a line by adding a backslash to the string.

print """\  Usage: thingy [OPTIONS]  -h      Display this usage message   -H hostname    Hostname to connect to   """

The string is connected by the plus sign and can be doubled by the multiplication sign.
Strings can also be connected by writing them together, but they cannot be used on variables:

'Py' 'thon'

The string can be accessed like an array, and 0 represents the start character. Specifically,-1 indicates the last character, and-2 indicates the last 2nd characters.

The string can be accessed in slices. In particular, a negative number is used for slicing.

S = "abcde" s [0] s [-1] s [-5] s [:-1] # remove the last character, for example, line break + --- + | P | y | t | h | o | n | + --- + 0 1 2 3 4 5 6-6-5-4-3-2-1

When slice access is out of bounds, an empty set is obtained. No need for access control.

A single character cannot be assigned a value because the string is unchangeable. If you need a different string, create a new string and use slice to easily achieve this.
The built-in function len returns the length of the string.

Use encode and decode to ask about string encoding and decoding. (A special file is required to discuss the encoding type issues)

Common Methods:
Startswith detection start
Example:

1. a = 'leonis'
If a. startswith ('le '):
Print 'le'
Endswith detection end
Example:

1. a = ‘leonis'if a.endswith(‘is'):print ‘is'

Whether the in check is a part of it
Example:

1. a = ‘leonis'if ‘o' in a:print ‘a'

Find query contains
Example:

1. a= ‘leonis'if a.find(‘on') != -1:print(‘on')

Join connection string
Example:

1.

 a = ' '
mylist = ['Brazil','Russia','India','China']print a.join(mylist)

2.

mylist = ['Brazil','Russia','India','China']print ‘_'.join(mylist)

Split string

1.

 b = 'my..name..is..leonis'print bprint b.split('..')

2.

b = ‘my..name..is..leonis'print bprint b.split(‘..',1)

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