Python: bool() function
bool() function
The bool() function is used to convert a value to a Boolean.
Syntax:
class bool([x])
Version:
(Python 3.2.5)
If x is false or omitted, this returns False; otherwise it returns True. bool is also a class, which is a subclass of int. Class bool cannot be subclassed further. Its only instances are False and True.
Return value:
Boolean Values (True/False).
Example: Python bool() function
val = True
print("val = ", bool(val))
val = False
print("val = ", bool(val))
val = 5
print("val = ", bool(val))
val = 0
print("val = ", bool(val))
val = bool()
print("val = ", bool(val))
Output:
val = True val = False val = True val = False val = False
Check if a list is empty or not ?
l = []
if not l:
print("List is empty.")
else:
print("List is not empty.")
l = [1, 2, 3]
if not l:
print("List is empty.")
else:
print("List is not empty.")
Output:
List is empty. List is not empty.
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Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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