如何查找值是否包含字符

Question

Right now am planning to add items into the database. The item name, price and all are all entered by the users. How do I find if theres any alphabets when entering the price? i tried using.isnumber() but it seems to be reading my decimal point as a character as well.

while True:
        itemPrice = input("Please Enter Item Price: ")
        if str(itemPrice).isnumeric()  == False:
            print("Please enter a value!")
        else:
            print(itemPrice)
            break

For example, they allow if i enter 5 but not 5.5 and since this is item price it should have decimals.

Answer 1

You can catch exceptions,

while True:
    itemPrice = input("Please Enter Item Price: ")
    try:
        itemPrice = float(itemPrice)
        print(itemPrice)
        break
    except ValueError:
        print("Please enter a value!")

Answer 2

you can use try/except block

a = 3.5345
a=str(a)

try: #if it can be converted to a float, it's true
    float(a) 
    print(True)
except: # it it can't be converted to a float, it's false
    print(False)

Answer 3

You could try using a for loop to check:

def containsAlpha(x):
    if True in [char.isalpha() for char in x]:
        return True
    return False

while True:
    itemPrice = input("Please Enter Item Price: ")

    if containsAlpha(itemPrice):
        print("Please enter a value!")
    else:
        print(itemPrice)
        break