Question

如何将列表中的元素与下一个元素进行比较以查看它们是否相同？假设我有一个列表，我想用for循环遍历该列表，并打印出多少个数字，然后再输入不同的数字。

str_n = "5223888"
count = 1

#print(len(str_n))

number = [int(x) for x in str_n]
#print(number)

for i in number:
    while number[i] == number[i+1]:
        count+=1
        i+=1
    print(count, " ", i)

预期输出：

15221338

Answer 1

错误

执行for i in number时，将“ 2”重复两次，然后将“ 8”重复三次，这将导致错误的输出。
您没有在每次迭代中将count初始化为零。
for i in number迭代number中的值，而不是索引

更正代码

您可以使用以下代码：

str_n = "5223888"

number = [int(x) for x in str_n]

for i in set(number):
    print("Element " + str(i) + " occurs " + str(number.count(i)) + " times")

Answer 2

我花了一些时间来了解您的要求。在您的情况下，最好使用while循环

str_n = "5223888" 
#print(len(str_n))

number = [int(x) for x in str_n]
#print(number)
i=0;
while(i<len(number)): 
    storei=i
    count = 1
    while i+1<len(number) and number[i] == number[i+1]  :
        count+=1
        i+=1
    i+=1
    print("number is "+str(number[storei])+" count is "+str(count)))

输出

number is 5 count is 1
number is 2 count is 2
number is 3 count is 1
number is 8 count is 3

编辑在python3中打印您需要指定的输出

str_n = "522388"
#print(len(str_n))

number = [int(x) for x in str_n]
#print(number)
i=0;
while(i<len(number)): 
    storei=i
    count = 1
    while i+1<len(number) and number[i] == number[i+1]  :
        count+=1
        i+=1
    i+=1
    #print("number is "+str(number[storei])+" count is "+str(count))
    print(str(count)+str(number[storei]),end="")

在python 2中，您需要指定准确的输出，如

str_n = "522388"

import sys
#print(len(str_n))

number = [int(x) for x in str_n]
#print(number)
i=0;
while(i<len(number)): 
    storei=i
    count = 1
    while i+1<len(number) and number[i] == number[i+1]  :
        count+=1
        i+=1
    i+=1
    #print("number is "+str(number[storei])+" count is "+str(count))
    sys.stdout.write(str(count)+str(number[storei]))

Answer 3

当您写for i in number时，您可能是指for i in range(len(number))，它将使i成为number列表中的 indices 。

话虽如此，您实际上并不需要索引；当您说for num in number时，num是列表中的实际数字。您可以在没有索引的情况下完成以下操作：

count = 0
current = number[0]

for num in number:
  if num == current:
    count += 1
  else:
    print(count, current)    
    current = num
    count = 1

print(count, current) # print the last count

这给我们：

如何将一个元素的值与下一个元素进行比较

3 个答案: