What does += mean when used together in python?

For variable types, we can modify the variables in situ, which means that its storage space is readable and writable, such as list; for immutable types, its storage space is It is read-only and cannot be modified. If you need to perform certain operations on the immutable type to get new results, you need to create a new storage space to store the new results.

For variable types: = represents the append operation, that is, the in-place operation, which appends the content of another object to the object in place.

For immutable types: = represents a connection or sum operation, and the result of the operation will produce a new object.

>>> l = [1, 2, 3, 4, 5] >>> id(l) 43142024 >>> l += [0]*5 >>> l[1, 2, 3, 4, 5, 0, 0, 0, 0, 0] >>> id(l) 43142024

When using =, there is one before and after "l".

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>>> t = (1, 2, 3, 4, 5) >>> id(t) 45438232 >>> t += (0,)*5 >>> t(1, 2, 3, 4, 5, 0, 0, 0, 0, 0) >>> id(t) 45674568

When we replace the list with a tuple, the result changes again.

>>>s = "hello" >>> id(s) 45794056 >>>s += "world" >>> s'helloworld' >>> id(s) 45495920

The result is like a tuple, "s" is reassigned after using = to concatenate a string, and is no longer the previous variable. Reflected in the memory, "s" has been opened up an additional storage space to store the value.

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