List of functions in Python

General
1

I’m learning Python and want to understand the commonly used functions. Can someone share a list of important Python functions that are useful in real-world coding?

2

If you’re just getting started, focus on Python’s built-in functions—you’ll use these all the time in real projects:

  • print() – display output

  • len() – get length of a list, string, etc.

  • type() – check the data type

  • input() – take user input

  • int(), float(), str() – type conversion

  • range() – generate number sequences (loops)

  • sum(), min(), max() – basic calculations

  • sorted() – sort data

  • abs() – absolute value

  • enumerate() – loop with index

  • zip() – combine multiple iterables

  • open() – work with files

Once you’re comfortable with these, you’ll naturally start using library functions (like from math, datetime, os, pandas, etc.) based on what you’re building.

1 Like
3

Python has many built-in functions, but instead of memorizing all of them, it’s better to understand the common ones by category.

Some of the most used basic functions are:
print(), input(), type(), len(), help()

For numbers and math:
abs(), round(), min(), max(), sum(), pow()

For type conversion:
int(), float(), str(), bool(), list(), tuple(), set(), dict()

For working with sequences:
range(), sorted(), enumerate(), zip(), reversed()

For logic and checks:
all(), any(), isinstance(), id()

For advanced usage:
map(), filter(), reduce(), eval(), exec()

Python also lets you create your own functions using def, which is just as important as knowing built-ins.

So in practice, you don’t need the full list at once knowing the commonly used functions and understanding how to apply them matters more than memorizing every function Python provides.

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4

If you’re just starting out with Python, hera are the commonly used built-in functions that are essential for real-world coding:

Core Functions

  • print(), input() → Input/output

  • len(), type() → Data inspection

  • int(), float(), str() → Type conversion

Working with Data

  • list(), set(), tuple() → Data structures

  • min(), max(), sum(), round() → Calculations

Loops & Iteration

  • range(), enumerate(), zip() → Efficient looping

Functional Tools

  • map(), filter() → Data transformation

Sorting & Logic

  • sorted(), reversed() → Ordering

  • any(), all() → Conditions

File Handling & Debugging

  • open() → File operations

  • help(), dir() → Exploration

If you practice using these regularly in small projects or problems, you’ll get really comfortable with Python.

5

Great question. Instead of memorising everything, focus on functions that show up repeatedly in real coding, data work, and problem solving.

Core Built-in Functions

These are used across almost every Python program:

  • print() → Output results

  • input() → Take user input

  • len() → Get length of list, string, or collection

  • type() → Check data type

  • range() → Generate sequences for loops

These form the base of most scripts.

Data Handling Functions

Used heavily when working with lists and collections:

  • sum() → Add elements in a list

  • min() / max() → Find smallest or largest value

  • sorted() → Return a sorted version of data

  • list() / tuple() / set() → Convert data types

These are essential in both coding interviews and real applications.

Iteration and Mapping

Useful for transforming and filtering data:

  • map() → Apply a function to each element

  • filter() → Select elements based on a condition

  • enumerate() → Loop with index and value

  • zip() → Combine multiple iterables

These functions make code more concise and readable.

String Functions

Strings are everywhere in real-world tasks:

  • str() → Convert to string

  • int() / float() → Type conversion

  • format() or f-strings → Format output

  • split() / join() → Break and combine strings

These are critical for data cleaning and processing.

Functional and Utility Functions

Help in writing efficient logic:

  • any() → Returns True if any element is True

  • all() → Returns True if all elements are True

  • abs() → Absolute value

  • round() → Round numbers

Useful in validation and calculations.

File Handling Functions

Important for real-world applications:

  • open() → Open files

  • read() / write() → Read and write data

  • close() → Close file

Often used with context managers (with open(...)) for safer handling.

Object and Debugging Functions

Helpful during development:

  • dir() → List available methods of an object

  • help() → Get documentation

  • id() → Memory reference of an object

Useful when exploring new libraries or debugging.

Final Takeaway

You do not need to memorise all Python functions. Focus on:

  • Core functions like len, range, print

  • Data functions like sum, sorted, zip

  • Practical utilities like map, filter, open

These cover most real-world use cases. Mastering them improves both coding speed and clarity.

6

If you’re learning Python, you don’t need to memorize every function—just get comfortable with the ones that show up in everyday coding. Here are some commonly used Python functions that are genuinely useful in real-world work:

  • print() – Displays output to the console. You’ll use this constantly for debugging and showing results.

  • input() – Takes user input from the keyboard. Useful for simple programs and scripts.

  • len() – Returns the length of a list, string, or other collection. Very common in loops and validations.

  • type() – Tells you what type of data a variable holds (int, str, list, etc.). Helpful for debugging.

  • range() – Generates a sequence of numbers, mainly used in loops.

  • int(), float(), str() – Convert data from one type to another. You’ll use these a lot when handling input or data.

  • sum() – Quickly adds numbers in a list.

  • max() and min() – Find the largest or smallest value in a dataset.

  • sorted() – Returns a sorted version of a list without changing the original.

  • enumerate() – Lets you loop through items while keeping track of their index. Very useful in real projects.

  • zip() – Combines multiple lists so you can loop through them together.

  • open() – Opens files for reading or writing—essential for working with files and data.

If you focus on understanding these and practice them in small programs, you’ll cover a big portion of what’s used in real-world Python coding.

7

If you are learning Python, you do not need to memorize every function. Start with the ones used often in real-world coding, DSA, automation, data handling, and backend development.

Commonly Used Python Functions for Beginners

Input and output

  • print() – displays output

  • input() – takes user input

Type conversion

  • int() – converts to integer

  • float() – converts to decimal number

  • str() – converts to string

  • list() – converts to list

  • tuple() – converts to tuple

  • dict() – creates or converts to dictionary

  • set() – creates or converts to set

Length and range

  • len() – returns length of a string, list, tuple, or dictionary

  • range() – generates a sequence of numbers

Math and numbers

  • sum() – adds values

  • min() – returns the smallest value

  • max() – returns the largest value

  • abs() – returns absolute value

  • round() – rounds a number

  • pow() – calculates power

Sorting and iteration

  • sorted() – returns a sorted version

  • enumerate() – gives index and value while looping

  • zip() – combines multiple iterables

  • reversed() – reverses an iterable

Checking and filtering

  • any() – returns True if at least one value is true

  • all() – returns True if all values are true

  • isinstance() – checks data type

String functions

  • split() – breaks a string into parts

  • join() – joins items into a string

  • strip() – removes extra spaces

  • replace() – replaces text

  • lower() – converts to lowercase

  • upper() – converts to uppercase

  • find() – finds text position

List functions

  • append() – adds an item

  • extend() – adds multiple items

  • insert() – inserts an item at a position

  • remove() – removes an item

  • pop() – removes and returns an item

  • sort() – sorts the list

Dictionary functions

  • get() – safely gets a value

  • keys() – returns all keys

  • values() – returns all values

  • items() – returns key-value pairs

  • update() – updates dictionary values

Most useful for real-world coding

Start with:

print(), input(), len(), range(), sum(), min(), max(), sorted(), enumerate(), zip(), split(), join(), append(), get(), and items().

These functions appear again and again in Python projects, automation scripts, interviews, and DSA problems.

8

Python has a huge number of built-in functions, but instead of memorizing all of them, focus on learning the commonly used ones while building projects.

Some functions you’ll end up using a lot are:

  • print()

  • len()

  • type()

  • range()

  • input()

  • sum()

  • max()

  • min()

  • sorted()

  • enumerate()

  • zip()

The best way to remember functions is by actually using them in small programs. Over time, you’ll naturally recognize which function is useful for which situation.

Also, Python’s official documentation is surprisingly beginner-friendly, so it’s worth keeping it bookmarked while learning.