Home > Article > Backend Development > python basics--list
List
List is one of the most commonly used data types. Lists can achieve the most convenient storage, modification and other operations on data
1. Define the list
fruits = ['apple','banana','orange']
2. Access elements in the list through subscripts, and the subscripts start counting from 0
>>> fruits[0] 'apple' >>> fruits[2] 'orange' >>> fruits[-1] 'orange' >>> fruits[-2] 'banana'
3. Slicing
>>> fruits = ['apple','banana','orange','peal','grape'] >>> fruits[1:4] #取下标1到下标4之间的数,包括1但不包括4 ['banana', 'orange', 'peal'] >>> fruits[1:-1] #取下标1至-1之间的数,不包括-1 ['banana', 'orange', 'peal'] >>> fruits[0:3] #从头开始取,不包括3 ['apple', 'banana', 'orange'] >>> fruits[:3] #和上句一样 ['apple', 'banana', 'orange'] >>> fruits[3:] #从下标3到最后,到末尾只能这样取 ['peal', 'grape'] >>> fruits[0::2] #从头开始,步长为2,即隔一个取一个 ['apple', 'orange', 'grape'] >>> fruits[::2] #和上句一iy ['apple', 'orange', 'grape']
4. Append, append()
>>> fruits ['apple', 'banana', 'orange', 'peal', 'grape'] >>> fruits.append('newpeach') >>> fruits ['apple', 'banana', 'orange', 'peal', 'grape', 'newpeach']
5 .Insert element, insert()
Insert a watermelon at subscript 1
['apple', 'banana', 'orange', 'peal', 'grape', 'newpeach'] >>> fruits.insert(1,'watermelon') >>> fruits ['apple', 'watermelon', 'banana', 'orange', 'peal', 'grape', 'newpeach']
6. Modify the elements in the list
Change banana to cherry
>>> fruits ['apple', 'watermelon', 'banana', 'orange', 'peal', 'grape', 'newpeach'] >>> fruits[2]='cherry' >>> fruits ['apple', 'watermelon', 'cherry', 'orange', 'peal', 'grape', 'newpeach']
7. Delete
pop() will return the last element after deleting it by default
>>> fruits ['apple', 'watermelon', 'cherry', 'orange', 'peal', 'grape', 'newpeach'] >>> del fruits[2] #删除第二个元素 >>> fruits ['apple', 'watermelon', 'orange', 'peal', 'grape', 'newpeach'] >>> fruits.remove('orange') #删除指定的元素 >>> fruits ['apple', 'watermelon', 'peal', 'grape', 'newpeach'] >>> fruits.pop() #删除最后一个元素 'newpeach' >>> fruits ['apple', 'watermelon', 'peal', 'grape']
8. Extend extend()
>>> fruits ['apple', 'watermelon', 'peal', 'grape'] >>> vegetable = ['radish','cabbage','cucumber'] >>> fruits ['apple', 'watermelon', 'peal', 'grape'] >>> vegetable ['radish', 'cabbage', 'cucumber'] >>> fruits.extend(vegetable) >>> fruits ['apple', 'watermelon', 'peal', 'grape', 'radish', 'cabbage', 'cucumber']
9. Copy copy()
['apple', 'watermelon', 'peal', 'grape', 'radish', 'cabbage', 'cucumber'] >>> fruits2 = fruits.copy() >>> fruits2 ['apple', 'watermelon', 'peal', 'grape', 'radish', 'cabbage', 'cucumber']
10. Statistics count()
>>> fruits.count('apple') 1
11. Sort sort() and flip reverse()
>>> fruits ['apple', 'watermelon', 'peal', 'grape', 'radish', 'cabbage', 'cucumber'] >>> fruits.sort() >>> fruits ['apple', 'cabbage', 'cucumber', 'grape', 'peal', 'radish', 'watermelon'] >>> fruits.reverse() >>> fruits ['watermelon', 'radish', 'peal', 'grape', 'cucumber', 'cabbage', 'apple']
12. Get the subscript index ()
['watermelon', 'radish', 'peal', 'grape', 'cucumber', 'cabbage', 'apple'] >>> fruits.index('apple') 6 # 只返回找到的第一个下标
For more python basics-list related articles, please pay attention to the PHP Chinese website!