I am wondering if python has any function such as php empty function (http://php.net/manual/en/function.empty.php) which check if the variable is empty with following criteria
"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
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python
Yes, bool. It's not exactly the same -- '0' is True, but None, False, [], 0, 0.0, and "" are all False.
bool is used implicitly when you evaluate an object in a condition like an if or while statement, conditional expression, or with a boolean operator.
If you wanted to handle strings containing numbers as PHP does, you could do something like:
def empty(value):
try:
value = float(value)
except ValueError:
pass
return bool(value)
See section 5.1:
http://docs.python.org/library/stdtypes.html
Any object can be tested for truth value, for use in an if or while condition or as operand of the Boolean operations below. The following values are considered false:
None
False
zero of any numeric type, for example, 0, 0L, 0.0, 0j.
any empty sequence, for example, '', (), [].
any empty mapping, for example, {}.
instances of user-defined classes, if the class defines a __nonzero__() or __len__() method, when that method returns the integer zero or bool value False. [1]
All other values are considered true — so objects of many types are always true.
Operations and built-in functions that have a Boolean result always return 0 or False for false and 1 or True for true, unless otherwise stated. (Important exception: the Boolean operations or and and always return one of their operands.)
See also this previous answer which recommends the not keyword
How to check if a list is empty in Python?
It generalizes to more than just lists:
>>> a = ""
>>> not a
True
>>> a = []
>>> not a
True
>>> a = 0
>>> not a
True
>>> a = 0.0
>>> not a
True
>>> a = numpy.array([])
>>> not a
True
Notably, it will not work for "0" as a string because the string does in fact contain something - a character containing "0". For that you have to convert it to an int:
>>> a = "0"
>>> not a
False
>>> a = '0'
>>> not int(a)
True
Just use not:
if not your_variable:
print("your_variable is empty")
and for your 0 as string use:
if your_variable == "0":
print("your_variable is 0 (string)")
combine them:
if not your_variable or your_variable == "0":
print("your_variable is empty")
Python is about simplicity, so is this answer :)
Source: Stackoverflow.com