Python creates an empty list and explains the usage of append-Python Tutorial-php.cn

Python creates an empty list and explains the usage of append

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Release： 2018-05-04 14:11:55

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This article mainly introduces how to create an empty list in Python and how to use append. It has certain reference value. Now I share it with you. Friends in need can refer to it

Usage of list in Python : How to create a list, how to express elements in the list, how to modify and delete the list

Running environment: Python 3.6.2

0. Creation of an empty list:

l = list()

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Or:

l = []

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1.Creation and expression of elements in list

fruits = [&#39;apple&#39;, &#39;banana&#39;, &#39;pear&#39;, &#39;grapes&#39;, &#39;pineapple&#39;, &#39;watermelon&#39;]
fruits[2] #从0开始数起，第三个元素
pear

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2.Change of elements in list

fruits[2] = &#39;tomato&#39;
print(fruits)
[&#39;apple&#39;, &#39;banana&#39;, &#39;tomato&#39;, &#39;grapes&#39;, &#39;pineapple&#39;, &#39;watermelon&#39;]

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3. Add more elements to the end of the list

fruits.append(&#39;eggplant&#39;)
print(fruits)
[&#39;apple&#39;, &#39;banana&#39;, &#39;tomato&#39;, &#39;grapes&#39;, &#39;pineapple&#39;, &#39;watermelon&#39;, &#39;eggplant&#39;]

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4. How to intercept a certain paragraph in the list

print(fruit[: 2]) #从list的首元素开始截取，截取到位置&#39;3&#39;，但不包括第3个元素
[&#39;apple&#39;, &#39;banana&#39;]

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5. How to change consecutive elements in the list

fruits[:2] = [&#39;a&#39;, &#39;b&#39;]
print(fruits)
[&#39;a&#39;, &#39;b&#39;, &#39;tomato&#39;, &#39;grapes&#39;, &#39;pineapple&#39;, &#39;watermelon&#39;, &#39;eggplant&#39;]

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6 .How to delete a certain element in the list, or the entire list

fruits[:2] = [] #删除前两个元素
print(fruits)
[&#39;tomato&#39;, &#39;grapes&#39;, &#39;pineapple&#39;, &#39;watermelon&#39;, &#39;eggplant&#39;]
fruits[:] = [] #删除全部list元素
[]

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Python implementation method of creating a list and adding elements to the list_python

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