Python checks whether an object is a string type.

Python checks whether an object is a string type.

Purpose

Test whether an object is a string.

Method

The base class of the Python string is basestring, including the str and unicode types. Generally, the following methods can be used:
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Def isAString (anobj ):

Return isinstance (anobj, basestring)

However, the above method is powerless for instances of the UserString class.

Copy codeThe Code is as follows:
In [30]: B = UserString. UserString ('abc ')

In [31]: isAString (B)
Out [31]: False

In [32]: type (B)
Out [32]: <class 'userstring. userstring'>

The duck detection method commonly used in Python: If it is walking like a duck, it can be considered as a duck.

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Def isStringLike (anobj ):

Try:

Anobj. lower () + anobj +''

Except t:

Return False

Else:

Return True

The test results are as follows:

Copy codeThe Code is as follows:
>>> Import UserString
>>> B = UserString. UserString ('abc ')
>>> IsStringLike (B)
True
>>>

About Style

Execute the task according to your own tone. In this process, all errors and exceptions caused by non-matching are detected and handled. This processing method is called:
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EAFP: It's easier to ask forgiveness than permission.

Try/try t is a key tool to ensure the style.

Gossip about the UserString class

For version 2.x: as mentioned in the Python document, if versions earlier than Version 2.2 are not involved, use the str type instead of the UserString type.

For version 3.x: This module has been moved to the collection module.

There are two main methods for this class:
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Class UserString. UserString ([sequence])

The preceding example shows how to convert str () to str.
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Class UserString. MutableString ([sequence])

The string can also be changed! Look here:

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A = UserString. MutableString ('abc ')
A [0] = 'C'

In [10]:
Out [10]: 'cbc'

 
The Python document contains a line of italics. The original method is obsolete, and 3.0 is gone:
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Deprecated since version 2.6: The MutableString class has been removed in Python 3.0.