[英]using nested while loop instead of for loops
我为我创建了一个编码挑战
我想使用 while 循环更改嵌套列表的值而不创建新列表
这个 function 适用于单行嵌套列表,请参见下面的示例
基本上它的工作原理如下:启动循环检查第一个值是否为特定类型,如果是,则将值 go 替换出循环,再次启动循环->第一个值已被替换,因此索引已更新
它在下一个值之前,直到所有值都被替换
def insertdata(data):
data_added = False
n = len(listoflist[0])
index = 0
while not data_added and index != n:
if listoflist[0][index] is None:
listoflist[0][index] = data
data_added = True
else:
index += 1
if index == n:
print("\n The list is full, No more elements will be added \n")
我想扩展 function 以便它可以用多行和多列替换嵌套列表
output 应该是这样的
listoflist = [[None, None, None],[None, None, None]]
def _execute():
user_input = input("type in: ")
return user_input
while True:
def insertdata(_execute()):
input = 2
[[2, None, None],[None, None, None]]
input = 4
[[2, 4, None],[None, None, None]]
这里我有点卡住了
我的伪代码:
rowindex = 0
main loop
# start second loop
start second loop
# performs the operation for the row [rowindex][columnindex]
# if all values replaced in the row
# go back to main loop update the row count and procede with the next column
到目前为止,没有按预期工作
def insertdata(data):
row_index = 0
while row_index != len(listoflist):
# inner loop
data_added = False
n = len(listoflist[row_index])
index = 0
while not data_added and index != n:
if listoflist[row_index][index] is None:
listoflist[row_index][index] = data
data_added = True
else:
index += 1
# gets not executed
if index == n:
row_index += 1
break
问题是如何更新外循环中的rowindex,并用更新后的rowindex开始内循环?
单行列表示例
listoflist = [[None, None, None]]
def _execute():
user_input = input("type in: ")
return user_input
while True:
insertdata(_execute())
print(listoflist)
你可以这样做:
listoflist = [[None, None, None], [None, None, None]]
def insertdata(data):
row_index = 0
while row_index < len(listoflist):
# inner loop
data_added = False
n = len(listoflist[row_index])
index = 0
while index < n:
if listoflist[row_index][index] is None:
listoflist[row_index][index] = data
data_added = True
break
else:
index += 1
if index == n:
row_index += 1
if data_added:
break
for i in range(7):
insertdata(f'input {i}')
print(listoflist)
这给了你这个结果
[['input 0', None, None], [None, None, None]]
[['input 0', 'input 1', None], [None, None, None]]
[['input 0', 'input 1', 'input 2'], [None, None, None]]
[['input 0', 'input 1', 'input 2'], ['input 3', None, None]]
[['input 0', 'input 1', 'input 2'], ['input 3', 'input 4', None]]
[['input 0', 'input 1', 'input 2'], ['input 3', 'input 4', 'input 5']]
[['input 0', 'input 1', 'input 2'], ['input 3', 'input 4', 'input 5']]
在将新元素添加到列表后,您遇到了索引问题并且没有中断
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