Python:在列表中修改、添加和刪除元素


一、修改

代碼示例

motorcycles = ['honda', 'yamaha', 'suzuki'] 
print(motorcycles) 

motorcycles[0] = 'ducati' 
print(motorcycles)
運行結果

['honda', 'yamaha', 'suzuki'] 
['ducati', 'yamaha', 'suzuki']

二、添加

  (一)使用append()添加在末尾

代碼示例

motorcycles = ['honda', 'yamaha', 'suzuki'] 
print(motorcycles) 

motorcycles.append('ducati') 
print(motorcycles) 
方法append()將元素'ducati'添加到了列表末尾,而不影響列表中的其他所有元素:

['honda', 'yamaha', 'suzuki'] 
['honda', 'yamaha', 'suzuki', 'ducati']

  (二)使用insert()在列表任意位置插入元素(需要指定新元素的索引和值)

代碼示例

motorcycles = ['honda', 'yamaha', 'suzuki'] 
motorcycles.insert(0, 'ducati') 
print(motorcycles)
運行結果

['ducati', 'honda', 'yamaha', 'suzuki']

三、刪除

  (一)使用del語句刪除元素(知道要刪除的元素在列表中的位置)

代碼示例

motorcycles = ['honda', 'yamaha', 'suzuki'] 
print(motorcycles) 

del motorcycles[0] 
print(motorcycles)
運行結果

['honda', 'yamaha', 'suzuki'] 
['yamaha', 'suzuki']

  (二)使用方法pop()刪除元素(要將元素從列表中刪除,並接着使用它的值,可以使用pop()來刪除列表中任何位置的元素,只需在括號中指定要刪除的元素的索引即可。)

代碼示例①

motorcycles = ['honda', 'yamaha', 'suzuki'] 
print(motorcycles) 
popped_motorcycle = motorcycles.pop() 
print(motorcycles) 
print(popped_motorcycle)
運行結果①(.pop()刪除了列表中的末尾元素)

['honda', 'yamaha', 'suzuki'] 
['honda', 'yamaha'] 
suzuki
代碼示例②

motorcycles = ['honda', 'yamaha', 'suzuki'] 
first_owned = motorcycles.pop(0) 
print('The first motorcycle I owned was a ' + first_owned.title() + '.')
運行結果②

The first motorcycle I owned was a Honda.

  (三)根據值刪除元素(只知道要刪除的元素的值,不知道要從列表中刪除的值所處的位置。可使用方法remove(),可接着使用它的值)

代碼示例①

motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati'] 
print(motorcycles) 
motorcycles.remove('ducati') 
print(motorcycles)
運行結果①

['honda', 'yamaha', 'suzuki', 'ducati'] 
['honda', 'yamaha', 'suzuki']
代碼示例②

motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati']
print(motorcycles) 
too_expensive = 'ducati' 
motorcycles.remove(too_expensive) 
print(motorcycles) 
print("\nA " + too_expensive.title() + " is too expensive for me.")
運行結果②

['honda', 'yamaha', 'suzuki', 'ducati'] 
['honda', 'yamaha', 'suzuki'] 
A Ducati is too expensive for me.

 


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