We will complete this program that requires the definition of a function named computeGCRatio to

compute the GC content of a DNA molecule.

Given a single string as input where each character is one of G$,$ C$,$ T or A$,$ the GC ratio is computed as the

count of $G+C$ values over the total count of $A,T,C,G$ values. It is often written in texts as the following,

where each letter represents the count of instances in the string:

$\frac{G+C}{A+T+G+C}$

Plan:

What would be the input value $($parameter$)$ needed for your function to use?

What is the name of your function?

What does the function return?

How do you compute then return the ratio value?

# Lab $8$

# PUT YOUR DEFINITION OF THE FUNCTION computeGCRatio HERE!

# Hint: your function will need $4$ counter variables $($ one for each

# letter. And you will need to write a loop that steps through each

# character in the string

def computeGCRatio$($ # what is$/$are the parameters needed here?

# complete the logic here

# Main program to test the calculation

dnaFragment $=$ input $("$Enter the DNz sequence: $")$

gcratio $=$ computeGCRatio$($dnaFragment$)$ # to test your function

print $("$For the sequence:", dnaFragment$)$

print $("$The GC$-$Ratio is $\{$:$6\mathrm{.}3f\}".$ format $($gcratio$)$

Some example data you can use to check if your

computation is correct:

$(0\mathrm{.}462)$