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pythonstringsplitdel

functionality of del statement

I wonder why if I split a string with multiple characters into a list, then del function works only if I save the list into a new object? Example:

x = 'Hello world'
del x.split()[0]
print(x)
out: Hello world

y = x.split()
del y[0]
print(y)
out: ['world']
Solution

  • First, x.split() creates a list that is entirely independent of x (even ignoring the fact that str values are immutable); modifying that list won't affect x in any way.

    Second, you didn't save a reference to the list returned by x.split(), so even though del x.split()[0] does mutate that list, once the statement completes, the entire list is subject to garbage collection.

    In your second example, you do have a reference t the return value of x.split(0), so you can observe the result of del.