While strings can be multiplied by integers to create a repeating sequence, strings cannot be multiplied by floats. Otherwise, Python returns an error.
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In this article, we\u2019re going to talk about the \u201ctypeerror: can t multiply sequence by non-int of type \u2018float\u2019\u201d error and why it is raised. We\u2019ll walk through an example scenario with this error present so that we can solve it.<\/p>\n\n\n\n
Let\u2019s take a look at our error message and see what it tells us:<\/p>\n\n\n\n
typeerror: can't multiply sequence by non-int of type 'float'<\/pre><\/div>\n\n\n\nOur error is a TypeError. This means that we\u2019re trying to perform an operation on a value whose data type does not support that operation. For instance, if you try to concatenate an integer and a string, a type error is raised.
<\/p>\n\n\n\nThe error is telling us that we\u2019re multiplying a sequence, also known as a string<\/a>, by a floating-point number<\/a>. This is not supported in Python.
<\/p>\n\n\n\nThere are two types of numbers in Python: integers and floating-point numbers. Integers are whole numbers whereas floating-point numbers are decimals.
<\/p>\n\n\n\nStrings can be multiplied by integers. Consider this example:<\/p>\n\n\n\n
scone = "Scone"\nprint(scone * 3)<\/pre><\/div>\n\n\n\nOur code returns: SconeSconeScone. When you multiply a string by an integer<\/a>, it creates a repeating sequence of that string.
<\/p>\n\n\n\nStrings cannot be multiplied by floating point numbers. If you tried to multiply our \u201cscone\u201d string by 3.3, what would Python do? You can\u2019t have .3 of a string. Hence, an error is returned.<\/p>\n\n\n\n
An Example Scenario<\/h2>\n\n\n\n
This error is commonly found when working with input() statements<\/a>. Let\u2019s take a look at a program that calculates a 5% discount on a purchase made at a store.
<\/p>\n\n\n\nvalue = input("How much has the customer spent? ")\ndiscount = 0.05\n\nfinal_cost = value - (value * discount)\nprint(round(final_cost, 2))<\/pre><\/div>\n\n\n\nWe\u2019ve declared a variable<\/a> called value which stores how much the customer has spent on a purchase. This value is collected from the user using the input() method.
<\/p>\n\n\n\nNext, we have declared a variable called discount. This stores the 5% discount that we are going to apply to purchases as a decimal number. We then calculate the percentage discount by multiplying \u201cvalue\u201d and \u201cdiscount\u201d together. We then subtract this number from the total cost of the product.
<\/p>\n\n\n\nWe use the round() method<\/a> to round the value of \u201cfinal_cost\u201d to two decimal places. Then, we print this value to the console.
<\/p>\n\n\n\nLet\u2019s try to run our code:<\/p>\n\n\n\n
How much has the customer spent? 12.99\nTraceback (most recent call last):\n File "main.py", line 4, in <module>\n\tfinal_cost = value - (value * discount)\nTypeError: can't multiply sequence by non-int of type 'float'<\/pre><\/div>\n\n\n\nOh no. An error has been returned. Let\u2019s fix this error.<\/p>\n\n\n\n
The Solution<\/h2>\n\n\n\n
The error \u201ctypeerror: can’t multiply sequence by non-int of type \u2018float\u2019\u201d is caused by multiplying a string and a floating-point number together.
<\/p>\n\n\n\nThis error occurred in our earlier program because input() returns a string. This means that even if we insert a number into our program it will be stored as a string.
<\/p>\n\n\n\nTo solve this problem, we can convert the value the user inserts into the program to a floating-point number. We can do this using the float() method<\/a>:<\/p>\n\n\n\n
value = float(input("How much has the customer spent? "))\ndiscount = 0.05\n\nfinal_cost = value - (value * discount)\nprint(round(final_cost, 2))<\/pre><\/div>\n\n\n\nThe float() method is surrounded by the input() method. The float() method converts the string value returned by input() into a floating-point number. This allows us to multiply \u201cvalue\u201d and \u201cdiscount\u201d because they are both numbers.
<\/p>\n\n\n\nLet\u2019s try to run our code again:<\/p>\n\n\n\n
How much has the customer spent? 12.99\n12.34<\/pre><\/div>\n\n\n\nOur code works! Our program tells us that a 5% discount on the value of a $12.99 purchase makes the cost of the final product $12.34.<\/p>\n\n\n\n