In modules where a set of string literals is needed it can be declared as
values = ['hello', 'world']
But I have seen many experienced python programmers write
values = 'hello world'.split()
obviously considering it more readable. (I also think I have seen this in the python standard library source, but I'm not sure)
Does any python guide cite either of them as the preferred style, or does it come down to personal preference?
In some instances, when you have longer strings, it's shorter and arguably more readable to use a .split() than to write out a list.
In your case, with a small string, it doesn't really matter; I would use just a list because .split() is longer. It really depends on your preference.
values = ['hello', 'world'] should be more efficient. Also explicitly shows that values is a list of strings.
We can look at the source code.
split source codeIt starts by initializing a new list:
PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
Then doing the separator parameter lookup:
while ((j < str_len) && (maxcount-- > 0)) {
for(; j < str_len; j++) {
/* I found that using memchr makes no difference */
if (str[j] == ch) {
SPLIT_ADD(str, i, j);
i = j = j + 1;
break;
}
}
}
SPLIT_ADD actually calls PyList_SET_ITEM which inserts a certain object to the memory array.
Even without actually checking time differences, I can only assume that this lookup will be slower (even if a bit) than strictly initializing a list.
