How to divide numbers from a text file?

Question

This is my file text:

Covid-19 Data
Country / Number of infections / Number of Death
USA  124.356  2.236
Netherlands  10.866  771
Georgia  90  NA
Germany  58.247  455

I created a function to calculate the ratio of deaths compared to the infections, however it does not work, because some of the values aren't floats.

f=open("myfile.txt","w+")

x="USA" + " " + " " + "124.356" + " " + " " + "2.236"
y="Netherlands" + " " + " " + "10.866" + " " + " " + "771"
z="Georgia" + " " + " " + "90" + " " + " " + "NA"
w="Germany" + " " + " " + "58.247" + " " + " " + "455"

f.write("Covid-19 Data" + "\n" + "Country" + " " + "/" + " " + "Number of infections" + " "  + "/" + " " + "Number of Death" + "\n")
f.write(x + "\n")
f.write(y + "\n")
f.write(z + "\n")
f.write(w)

f.close()

with open("myfile.txt", "r") as file:


        try:
            for i in file:
                t = i.split()
                    result=float(t[-1])/float(t[-2])
                    print(results)
        except:
            print("fail")
        file.close()

Does someone have an idea how to solve this problem ?

Answer 1

You can do the following:

with open("myfile.txt", "r") as file:
    for i in file:
      t = i.split()

      try:
        result = float(t[-1]) / float(t[-2])
        print(result)
      except ValueError:
        pass

At the time you don't know if the values you are trying to divide are numeric values or not, therefore surrounding the operation with a try-catch should solve your problem.

If you want to become a bit more "clean" you can do the following:

def is_float(value):
  try:
    float(value)
  except ValueError:
    return False

  return True

with open("myfile.txt", "r") as file:
    for i in file:
      t = i.split()
      if is_float(t[-1]) and is_float(t[-2]):
        result = float(t[-1]) / float(t[-2])
        print(result)

The idea is the same, however.

Answer 2

I used the same file that you attached in your example. I created this function hopefully it helps:

with open("test.txt","r") as reader:
    lines = reader.readlines()

for line in lines[2:]:
    line = line.replace(".","") # Remove points to have the full value
    country, number_infections, number_deaths = line.strip().split()
    try:
        number_infections = float(number_infections)
        number_deaths = float(number_deaths)
    except Exception as e:
        print(f"[WARNING] Could not convert Number of Infections {number_infections} or Number of Deaths {number_deaths} to float for Country: {country}\n")
        continue
    ratio = number_deaths/number_infections
    print(f"Country: {country} D/I ratio: {ratio}")

As you can see I avoided the headers of your file using lines[2:] that means that I will start from row 3 of your file. Also, added try/exception logic to avoid non-float converts. Hope this helps!

Edit Just noticed that the format for thousands is used with "." instead "," in that case the period was removed in line 7 .

The results for this execution is:

Country: USA D/I ratio: 0.017980636237897647
Country: Netherlands D/I ratio: 0.07095527332965212

[WARNING] Could not convert Number of Infections 90.0 or Number of Deaths NA to float for Country: Georgia

Country: Germany D/I ratio: 0.007811561110443456

Answer 3

Fixed the following:

• The first two lines in your text-file are headers. These need to be skipped
• 'NA' Can't be converted to zero
• If there is a 0 in your data, your program would crash. Now it wouldn't.

f=open("myfile.txt","w+")

x="USA" + " " + " " + "124.356" + " " + " " + "2.236"
y="Netherlands" + " " + " " + "10.866" + " " + " " + "771"
z="Georgia" + " " + " " + "90" + " " + " " + "NA"
w="Germany" + " " + " " + "58.247" + " " + " " + "455"

f.write("Covid-19 Data" + "\n" + "Country" + " " + "/" + " " + "Number of infections" + " "  + "/" + " " + "Number of Death" + "\n")
f.write(x + "\n")
f.write(y + "\n")
f.write(z + "\n")
f.write(w)

f.close()

with open("myfile.txt", "r") as file:

        #Skipping headers
        next(file)
        next(file)

        try:
            for i in file:
                t = i.split()

                #Make sure your code keeps working when one of the numbers is zero
                x = 0
                y = 0

                #There are some NA's in your file. Strings not representing
                #a number can't be converted to float
                if t[1] != "NA":
                    x = t[1]
                if t[2] != "NA":
                    y = t[2]

                if x == 0 or y == 0:
                    result = 0
                else:
                    result=float(x)/float(y)

                print(t[0] + ": " + str(result))

        except:
            print("fail")
file.close()

Output:

USA: 55.615384615384606
Netherlands: 0.014093385214007782
Georgia: 0
Germany: 0.12801538461538461

Answer 4

Your header line in the file is Covid-19 Data . this is the first line and when you call t=i.split() you then have a list t which has data ['Covid-19', 'Data']

you cannot convert these to floats since they have letters in them. Instead you should read the first 2 header line before the loop and do nothing with them. However you are then going to have issues with Georgia as "NA" also cannot be converted to a float.

A few other points, its not good practice to have a catch all exception. Also you dont need to close the file explicitly if you open the file using a with statement.