如何在列表中搜索项目 - python

Question

This is probably a very simple program but I tried to find an item in a list (in python) and it just doesn't seem to work.

I made a simple list called Names and had variables:

found=False
index=0

I made another variable Searchname that contains a user entered string (a name) although there seems to be an error.

while found==False and index<=(len(Names)-1):
    index=index + 1
    if Searchname==Names[index]:
        found=True

        print('Found')

    else:
        print('Not found')  

I tried searching for an answer online but they were really complicated and I really hope that there might be some manageable solutions here.

Answer 1

您可以使用in运算符简单地检查一个元素是否存在。

item in my_list

Answer 2

Generally to check if an item is in a list you could as Python to check for that. But this would be case-sensitive. Otherwise you would have to lowercase the list first.

names = ['Mike', 'John', 'Terry']
if 'Mike' in names:
    print ("Found")
else:
    print ("Not Found")

Answer 3

You can use the in operator to search elements in a list. it will return True if that element is present in the list else False .

if Searchname in Names:
    found=True
    print('Found')
else:
    print('Not found')

Answer 4

This is one of the simplest ways to find the index of an item in a list. I'll use an example to explain this. Suppose we have a list of fruits(List_Of_Fruits) and we need to find the index of a fruit(Fruit_To_Search),we can use the given code.

The main part is the function index() its syntax is list.index(item) this will give the index of 'item' in 'list'

 #A list with a bunch of items(in this case fruits) List_Of_Fruits = ["Apples" , "Bananas" , "Cherries" , "Melons"] #Getting an input from the user Fruit_To_Search = input() #You can use 'in' to check if something is in a list or string if Fruit_To_Search in List_Of_Fruits: #If the fruit to find is in the list, Fruit_Index = List_Of_Fruits.index(Fruit_To_Search) #List_Of_Fruits.index(Fruit_to_Search) gives the index of the variable Fruit_to_Search in the list List_Of_Fruits print(Fruit_To_Search,"exists in the list. Its index is - ",Fruit_Index) else: print(Fruit_To_Search,"does not exist in the list"