[python3]: 50个【空元素】初始化数据结构【list】

[python3]:  50个【空元素】初始化数据结构【list】

 

 

 

 

一、需求

 

　　1、　　需求：用50个空元素，初始化一个数据结构‘列表’。　　lst　　=　　[  '' for i in range(50)  ]

 

　　2、　　需求：　　改变某个列表元素的值。　　lst　　=　　[  '' for i in range(50)  ]　;　　lst[variable]  =  variable ;

 

 

二、代码：

#!/usr/bin/env python3


#  set 50 empty elements for a list
ls = [  '' for i in range(50) ]


#  change the first element value of a list to 100 
ls[0] = 100


#  name:  trace(ls):
#  function:  display elements of a list
#  parameters:  list
#  return:  none
def trace(ls):
    id = 0
    for e in ls:
        print(f"[index_{id}]\t:=\t{e}")
        id = id + 1


#  entry point
if __name__ == '__main__' :
    trace(ls)

 

 

三、运行结果：

[index_0]    :=    100
[index_1]    :=    
[index_2]    :=    
[index_3]    :=    
[index_4]    :=    
[index_5]    :=    
[index_6]    :=    
[index_7]    :=    
[index_8]    :=    
[index_9]    :=    
[index_10]    :=    
[index_11]    :=    
[index_12]    :=    
[index_13]    :=    
[index_14]    :=    
[index_15]    :=    
[index_16]    :=    
[index_17]    :=    
[index_18]    :=    
[index_19]    :=    
[index_20]    :=    
[index_21]    :=    
[index_22]    :=    
[index_23]    :=    
[index_24]    :=    
[index_25]    :=    
[index_26]    :=    
[index_27]    :=    
[index_28]    :=    
[index_29]    :=    
[index_30]    :=    
[index_31]    :=    
[index_32]    :=    
[index_33]    :=    
[index_34]    :=    
[index_35]    :=    
[index_36]    :=    
[index_37]    :=    
[index_38]    :=    
[index_39]    :=    
[index_40]    :=    
[index_41]    :=    
[index_42]    :=    
[index_43]    :=    
[index_44]    :=    
[index_45]    :=    
[index_46]    :=    
[index_47]    :=    
[index_48]    :=    
[index_49]    :=    

 

 

四、参考资料：

 

　　1、　　Python3 列表|菜鸟教程　　--　　https://www.runoob.com/python/python-lists.html