A case analysis of true,false condition judgment in Python

Source: Internet
Author: User
The examples in this paper describe the usage of true,false conditional judgment in Python. Share to everyone for your reference. The specific analysis is as follows:

Programmers with programming experience know the wording of conditional statements:
Take C + + as an example:

The code is as follows:

if (condition)
{
DoSomething ();
}


The syntax for conditional judgments in Python is as follows:

The code is as follows:

if (condition):
DoSomething ()


So when is the condition in the conditional statement true and false?
In high-level languages such as C++/java, the condition is false if the value of the condition is 0 or if the referenced object is a null pointer.
In Python if condition is ", (), [],{},none,set () then the condition is flase, otherwise true.
The following is a test statement for Python:
1. Testing for strings

The code is as follows:

>>> condition= '
>>> print ' True ' if condition Else ' False '
False
>>> condition= ' Test '
>>> print ' True ' if condition Else ' False '
True


2. Testing for the original group

The code is as follows:

>>> condition= ()
>>> print ' True ' if condition Else ' False '
False
>>> (condition=)
>>> print ' True ' if condition Else ' False '
True


3. Testing for the list

The code is as follows:

>>> condition=[]
>>> print ' True ' if condition Else ' False '
False
>>> condition=[' A ', ' B ']
>>> print ' True ' if condition Else ' False '
True


4. Testing for Dictionaries

The code is as follows:

>>> condition={}
>>> print ' True ' if condition Else ' False '
False
>>> condition={' k ': ' V '}
>>> print ' True ' if condition Else ' False '
True


5. Test for None

The code is as follows:

>>> Condition=none
>>> print ' True ' if condition Else ' False '
False


6. Test for Set ()

The code is as follows:

>>> Condition=set ()
>>> print ' True ' if condition Else ' False '
False
>>> Condition.add (' a ')
>>> print ' True ' if condition Else ' False '
True

Hopefully this article will help you with Python programming.

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