Python method of detecting whether an object is a string class

This article mainly introduces the Python detection of whether an object is a string class method, that is, detection is an object is a string object, this article also explained an interesting method of judgment, the need for friends can refer to the

Objective

Test whether an object is a string

Method

The base class for Python strings is basestring, which includes STR and Unicode types. You can generally use the following methods:

The code is as follows:

def isastring (anobj):

Return Isinstance (anobj,basestring)

However, the above methods for the UserString class of examples, powerless.

The code is as follows:

In [m]: b=userstring.userstring (' abc ')

In [to]: isastring (b)

OUT[31]: False

In [i]: type (b)

OUT[32]:

The duck Judge method commonly used in Python: if it walks like a duck and barks like a duck, it can be considered a duck.

The code is as follows:

def isstringlike (anobj):

Try

Anobj.lower () + Anobj + '

Except

Return False

Else

Return True

The test results are as follows:

The code is as follows:

>>> Import userstring

>>> b=userstring.userstring (' abc ')

>>> Isstringlike (b)

True

>>>

About Style

Perform the task in its own tone, detecting and handling all errors and exceptions generated by the mismatch during this process. This approach is called:

The code is as follows:

Eafp:it ' s easier to ask forgiveness than permission.

Try/except is the key tool to ensure this style.

Gossip about the UserString class

for 2. X version: The Python document mentions that if you do not refer to a previous version of 2.2, consider using the STR type directly instead of the userstring type.

For 3. X version: The module has been moved to the collection module.

There are two main methods of this class:

The code is as follows:

Class userstring.userstring ([sequence])

Use the previous example already, note that you can use STR () to convert to STR type

The code is as follows:

Class userstring.mutablestring ([sequence])

Strings can also change Oh! Look here:

The code is as follows:

A=userstring.mutablestring (' abc ')

A[0]= ' C '

In [ten]: a

OUT[10]: ' CBC '

The Python document has a line in bold, which is already a deprecated method, and 3.0 is gone:

The code is as follows:

Deprecated since version 2.6:the mutablestring class has been removed in Python 3.0.