Python equivalent for C++ STL vector/list containers

Question

Is there something similar in Python that I would use for a container that’s like a vector and a list?

Any links would be helpful too.

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Answer 1

You can use the inbuilt list – underlying implementation is similar to C++ vector. Although some things differ – for example, you can put objects of different type in one and the same list.

http://effbot.org/zone/python-list.htm

N.B.: Please keep in mind that vector and list are two very different data structures. List are heterogeneous, i.e. can store different object types, while C++ vectors are homogeneous. The data in vectors is stored in linear arrangement whereas in list is a collection of references to the type and the memory address of the variables.

Answered By: Johan Kotlinski

Answer 2

Lists are sequences.

see http://docs.python.org/tutorial/datastructures.html

append is like push_back, see the other methods as well.

Answered By: Umut Tabak

Answer 3

Have a look at Python’s datastructures page. Here’s a rough translation:

() => boost::Tuple (with one important distinction, you can’t reassign values in a Python tuple)
[] => std::vector (as the comments have aluded towards, lacks memory characteristics associated with vectors)
[] => std::list
{} => tr1::unordered_map or boost::unordered_map (essentially a hash table)
set() => std::set

Answered By: wheaties

Answer 4

Python also has as part of the standard library an array type which is more efficient and the member type is constrained.

You may also look at numpy (not part of the standard library) if you need to get serious about efficient manipulation of large vectors/arrays.

Answered By: Paul

Answer 5

py	cpp
deque	deque
PriorityQueue (or you may use heapq)	priorityqueue
set	unordered_set
list	vector
defaultdict(int)	unordered_map
list	stack
deque	queue
dict .get(val,0)	unordered_map

in py >= 3.7, dict remember insert order. https://stackoverflow.com/a/51777540/13040423

In case you need TreeMap / TreeSet

https://github.com/grantjenks/python-sortedcontainers

Answered By: AsukaMinato

Answer 6

The cstl library wrapped commonly used C++ STL libraries including vector, unordered_map, and unordered_set for Python. It uses purely C++ implementation and does not have the copy-on-write issue that happens in all python objects. See
https://github.com/fuzihaofzh/cstl for how to install and use.

Install it from pip

pip install cstl

Convert python objects into cstl objects:

import cstl

# Directly covert containers from python
v = cstl.frompy({"1":[1,2,3], "2":[4,5,6]}) # convert python object to cstl object
v["1"][2] = 10 # access cstl object
pv = cstl.topy(v) # convert cstl object to python object 
print(pv)

Answered By: maple

Python equivalent for C++ STL vector/list containers

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