CODEWITHSUNDEEP
pythonstring
user4637416
user4637416

Reputation:

Summing elements of string in Python

I am new comer to python. I started to read a book published by MIT's professor about python. I got an exercise from this book. I tried to solve this but i could not.

Problem: Let s be a string that contains a sequence of decimal numbers separated by commas, e.g., s = '1.23,2.4,3.123' . Write a program that prints the sum of the numbers in s. i have to find out the sum of 1.23,2.4, and 3.123

So far i made some codes to solve this problem and my codes are follwoing: 

s = '1.23,2.4,3.123'
total = 0
for i in s:
    print i
    if i == ',':

Please,someone help me how can go further?

Upvotes: 2

Views: 974

Answers (3)

Kasravnd
Kasravnd

Reputation: 107287

All you need is first splitting your string with , then you'll have a list of string digits :

>>> s.split(',')
['1.23', '2.4', '3.123']

Then you need to convert this strings to float object till you can calculate those sum, for that aim you have 2 choice :

First is using map function :

>>> sum(map(float, s.split(',')))
6.753

Second way is using a generator expression within sum function :

>>> sum(float(i) for i in s.split(','))
6.753

Upvotes: 4

TessellatingHeckler
TessellatingHeckler

Reputation: 28983

It's much less Pythonic, and more effort, to walk through the string and build up the numbers as you go, but it's probably more in keeping with the spirit of a beginner working things out, and more of a continuation of your original code:

s = '1.23,2.4,3.123'
total = 0
number_holder_string = ''

for character in s:
    if character == ',':    # found the end of a number
        number_holder_value = float(number_holder_string)
        total = total + number_holder_value
        number_holder_string = ''

    else:
        number_holder_string = number_holder_string + character

print total

That way, number_holder_string goes:

''
'1'
'1.'
'1.2'
'1.23'
found a comma -> convert 1.23 from string to value and add it.
''
'2'
'2.'
etc.

Upvotes: 0

Pietro Battiston
Pietro Battiston

Reputation: 8380

It is much simpler to use str.split(), like in

s = '1.23,2.4,3.123'
total = 0
for i in s.split(','):
    total += float(i)

Upvotes: 0

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