Python Tutorial - dir and help Function

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Earlier we have learned many functions provided by strings, including split(), join(), find(), index(), etc., but this is far from all its methods. Due to the limited space, this chapter can only give you some of the most used functions. As for other functions, the reader can check them by using the dir() and help() functions introduced in this section.

The Python dir() function is used to list the entire contents of a class or a module, including variables, methods, functions, and classes. Its usage is:


obj represents the object to be viewed. obj can be left unwritten, at which point dir () lists the variables, methods, and defined types in the current scope.

The Python help() function is used to view the help documentation of a function or module. Its usage is:


obj represents the object to be viewed. obj can be left unwritten, and help() will enter the help subroutine.

After mastering the above two functions, we can review the usage and functions of all methods, functions, variables, and classes in Python.

[Example] Use dir() to view all methods supported by the string type (str):


The output is:


[Example] Use help () to see the usage of upper() function in str type:


The output is:

Help on method_descriptor:

upper(self, /)
  Return a copy of the string converted to uppercase.

As you can see, the upper() function is used to convert the letters in the string to uppercase and return a new string.

Note that when using help() to view the usage of a function, the function name cannot be enclosed in parentheses. For example, it is wrong to write the above command as help (str.upper ()).


The output is:

TypeError    raceback (most recent call last)
[ipython-input-5-f8bc63c28e1a] in [module]
----> 1 help(str.upper())

TypeError: descriptor 'upper' of 'str' object needs an argument


More Tutorials:

Python Installation - Linux (Ubuntu)
Python Installation - Mac OS
Integrated Development Environment - IDE
Python - Basic Variables
Python - Sequence Introduction
Python - Output Formatting
Python - Escape Character
Python - Type Conversion
Python - Numbers
Python – Arithmetic Operators
Python – Assignment Operators
Python – Comparison Operators
Python – Logical Operators
Python – Precedence and Associativity Operators
Python – Bytes Type and Usage
Python – Long & Raw Strings
Python – Concatenate Function
Python – Slice Function
Python – Length and Split Function
Python – Join and Count Function
Python – Find Function
Python – Index Function
Python – Alignment Function
Python – Startswith and Endswith Function
Python – String Case Conversion
Python – Remove Specified Character
Python – Encode and Decode Function
Python – dir and help Function
Python – Input Output Introduction
Python – Basic Operation
Python – Open Function
Python – Read Function
Python – Readline Function
Python – Write Function
Python – Close Function
Python – Seek and Tell Function
Python – Pickle Module
Python - File Input Module and Linecache Module
Python - Pathlib Module
Python - Pathlib Module
Python - os.path Module
Python - fnmatch Module
Python - Tuple Introduction
Python - List Introduction
Python - List Add Element
Python - List Delete Element
Python - List Modification Element
Python - List Find Element
Python - Dictionary Introduction
Python - Dictionary Basic Operation
Python - Dictionary Method Guide
Python - Set Collection
Python - Set Basic Operation
Python - Set Basic Method
Python - Frozenset Method
Python - If Condition I
Python - If Condition II
Python - While loop
Python - For loop
Python - Pass Statement
Python - Break Statement
Python - Zip Reverse Function
Python - Function Introduction
Python - Positional Parameters
Python - Key Arguments
Python - None and Return
Python - Variable Scope
Python - Local Function
Python - Closure Method
Python - Lamdba Expression

More Python Exercises:

Python String Exercises
Python List Exercises
Python Library Exercises
Python Sets Exercises
Python Array Exercises
Python Condition Statement Exercises