Question

I’m trying to write a function that takes two string arguments and returns the number of times a character from the first string occurs in the second string.

I am a complete beginner to python and am stumped. If anyone could point me in the right direction that would be great. I’ve been given this to start with:

def occurrences(text1, text2):
    """Return the number of times characters from text1 occur in text2

    occurrences(string, string) -> int
    """
    #Your code goes here

As you can see, 2 strings are needed. I thought that string 1 and string 2 would be sufficient but I have no idea how to to define them.

I have started with this so far and I’m not even having any success.

for c in "string":
    print c
    if c == char c in "string2":
        count += 1

I’m just throwing in random variables because how am I suppose to find char(A-Z) in a string that I dont even know?

EDIT: some of the tips you guys have told me i havn’t learned yet. For this question i should be using:

• for loop
• in

Some hints were given to me also:

Hint 1: You might find in useful for testing if one string is in another string.

Hint 2: Look at each character in the second argument and see if it is in the first argument.

Answer 1

Let’s start here and have a bit of a discussion:

As you can see, 2 strings are needed. I thought that string 1 and string 2 would be sufficient but I have no idea how to to define them.

They are provided for you: they are called text1 and text2. They come from the code that calls the functions. Were functions explained to you at some point? In your own words, how does a function work? What will the code look like that calls occurrences?

(Hint for the last part: there is an example given on your assignment sheet.)

Next:

if c == char c in "string2":

What do you expect this to mean? In particular, what do you expect char to mean? (Have you studied programming languages other than Python before?)