I’m new to python trying to code an engineering problem which requires user input of predefined entries. For example I want input of sequence of defined names . say John, Mike, Smith, Adam. I need user to input from this list of names only. The issue I am facing is user can input any name not in defined list of names mentioned above. I wanted to limit choice of names to select rather than code an error message that name is not in the list.
Can this input requirement be coded ?
Another way is to do it like this:
names = ['John', 'Mike', 'Smith', 'Adam']
name_num = 0
while name_num < 1 or name_num > len(names):
message = ''.join([f'{i+1}: {n}\n' for i,n in enumerate(names)])
name_num = int(input(message))
name = names[name_num-1]
print(name)
This also prints the available choises. The output looks like this:
1: John
2: Mike
3: Smith
4: Adam
_
If you want to handle bad inputs (no integers) you could also do something like this:
while name_num < 1 or res > len(names):
message = ''.join([f'{i+1}: {n}\n' for i,n in enumerate(names)])
try:
name_num = int(input(message))
except:
print('Input must be an integer value')
This is the code you need:
name_list = ['John', 'Mike', 'Smith', 'Adam']
user_input = input('Please input a name: ')
if not user_input in name_list:
print('Please input a valid name')
You can then adjust it depending on your case/needs.
Or this:
names = ["John", "Mike", "Smith, "Adam"]
print("1 : John")
print("2 : Mike")
print("3 : Smith")
print("4 : Adam")
number = int(input("input the number of the name you want"))
if number == 1:
name = "John"
So on and so forth.
try to take user input first and then loop the check if the user input is available in list or not . if not then raise exception. Show some of your code for more detail.
You could use recursion. Although, there is a limit for recursion as well. So it depends on your use case. If you want to go for recursion, here is how
list_names = ['John', 'Mike', 'Smith', 'Adam']
def func():
user_input = input('enter the name ')
if user_input in list_names:
print("valid user")
#your code
else:
print("Invalid user")
func()
Edit:
The proposed limit for recursion appears to be increasing. Information on the limit and python version can be found at
https://www.python.org/dev/peps/pep-0611/
