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Python - Adding all digits in string

How can i create a function that returns the sum of a string made up of 3 or more digits. For example, if the parameter/string is "13456". How can I return the result of (1*3 + 3*4 + 4*5 + 5*6). Thank you, all help is appreciated. Very new to python.

Another one-liner:
a = '13456'
print(sum([int(x)*int(y) for x, y in zip(a[1:], a[:-1])]))

You just need to go through the string, multiplying the actual value to the next value and add it to a variable to return it later.
def func(param):
ret = 0
for i in range(len(param)-1):
ret = ret + int(param[i]) * int(param[i+1])
return ret

my_string = "12345"
total = 0
for n in range(len(my_string) - 1):
total += int(my_string[n]) * int(my_string[n+1])

This function first turns your string into a list and then applies a map on it to convert all the elements to ints. Finally it uses a loop to access and multiply consecutive elements,
def str_sum(nstr):
nint = list(map(int, list(nstr)));
res = 0;
for i in range(len(nint[:-1])):
res += nint[i]*nint[i+1]
return res
Converting result of map into list using list(map(...)) is redundant in Python 2.7 but necessary in Python 3.X as map returns an object instead of a list.

Use range + sum
l = '13456'
sum([int(l[i])*int(l[i+1]) for i in range(len(l)-1)])
#Output:
#65
with range(len(l)-1), you can get the start, end indexes like below
Output:[0, 1, 2, 3]
Looping through the above list and indexing on list l,
int(l[i])*int(l[i+1]) # gives [1*3, 3*4 , ...]
Summing the output list
sum([1*3, 3*4 , ...]) # gives 65

def func(input):
return sum([int(input[i])*int(input[i+1]) for i in range(len(input)-1)])

Repeating characters results in wrong repetition counts

My function looks like this:
def accum(s):
a = []
for i in s:
b = s.index(i)
a.append(i * (b+1))
x = "-".join(a)
return x.title()
with the expected input of:
'abcd'
the output should be and is:
'A-Bb-Ccc-Dddd'
but if the input has a recurring character:
'abccba'
it returns:
'A-Bb-Ccc-Ccc-Bb-A'
instead of:
'A-Bb-Ccc-Cccc-Bbbbb-Aaaaaa'
how can I fix this?

Don't use str.index(), it'll return the first match. Since c and b and a appear early in the string you get 2, 1 and 0 back regardless of the position of the current letter.
Use the enumerate() function to give you position counter instead:
for i, letter in enumerate(s, 1):
a.append(i * letter)
The second argument is the starting value; setting this to 1 means you can avoid having to + 1 later on. See What does enumerate mean? if you need more details on what enumerate() does.
You can use a list comprehension here rather than use list.append() calls:
def accum(s):
a = [i * letter for i, letter in enumerate(s, 1)]
x = "-".join(a)
return x.title()
which could, at a pinch, be turned into a one-liner:
def accum(s):
a = '-'.join([i * c for i, c in enumerate(s, 1)]).title()

This is because s.index(a) returns the first index of the character. You can use enumerate to pair elements to their indices:
Here is a Pythonic solution:
def accum(s):
return "-".join(c*(i+1) for i, c in enumerate(s)).title()

simple:
def accum(s):
a = []
for i in range(len(s)):
a.append(s[i]*(i+1))
x = "-".join(a)
return x.title()

for each gives different result?

I tried to add the comma seprated value between the : seprated then multiply the whole value
For example, consider my value is 1,2,3:4,5,6
I want to add the 1+2+3 ,and 4+5+6 then multiply the result of this value so answer is 6 * 15 = 90
For my bellow data i want the result is 7.224 but this script gives 61.658886435
I don't know what is the problem in my script'
ar = "0.212,1.231,0.112:1.001,3.212,0.002:0.002,0.0001,1.1"
x_data = ar.split(":")
x_final = 1
x_add = 0
for i in x_data:
x_each = i.split(",")
for j in x_each:
x_add = x_add + float(j)
x_final = x_add * x_final
print x_final
Is any possible way to get the result without iterating loop? For above problem

This problem could be also solved in a functional way:
You have to multiply all values in the list - this is what functools.reduce + operator.mul for
You have to sum up all values in all inner lists - this is what sum for
Example:
In [5]: ar = "0.212,1.231,0.112:1.001,3.212,0.002:0.002,0.0001,1.1"
In [6]: import operator
In [7]: import functools
In [8]: functools.reduce(operator.mul, (sum(float(x) for x in s.split(',')) for s in ar.split(':')))
Out[8]: 7.223521582500001

I don't necessarily recommend this complicated expression, but you can do it with list comprehensions and avoid the for loops:
import operator
ar = "0.212,1.231,0.112:1.001,3.212,0.002:0.002,0.0001,1.1"
reduce(operator.mul, [sum([float(n) for n in e]) for e in [x.split(',') for x in ar.split(":")]], 1)

Use missed the initialize value as zero (x_add = 0) in each iterating. So your script add with the previous values
ar = "0.212,1.231,0.112:1.001,3.212,0.002:0.002,0.0001,1.1"
x_data = ar.split(":")
x_final = 1
for i in x_data:
x_each = i.split(",")
x_add = 0 # Here you not initialize it
for j in x_each:
x_add = x_add + float(j)
x_final = x_add * x_final
print x_final
!!! As from #jpmc26 and #soon comment. Avoid using eval, and conform your input string format.
Without looping use regex for to do it
Use regex for solve your problem without looping.
ar = "0.212,1.231,0.112:1.001,3.212,0.002:0.002,0.0001,1.1"
import re
ar = "("+ar #Add the ( with your data
ar = re.sub(r",","+",ar) #Substitute with + instead of ,
ar = re.sub(r"(?=\:|$)",")",ar) #look ahead for add `)` after colon
ar = re.sub(r"(?<=)\:","*(",ar) #Replace the color with *
#NOw you data look likes(0.212+1.231+0.112)*(1.001+3.212+0.002)*(0.002+0.0001+1.1)
#Finally evaluvate the string as a expression
print eval(ar)

'float' object is unsubscriptable

thats what I get:
TypeError: 'float' object is unsubscriptable
Thats what I did:
import numpy as N
import itertools
#I created two lists, containing large amounts of numbers, i.e. 3.465
lx = [3.625, 4.625, ...]
ly = [41.435, 42.435, ...] #The lists are not the same size!
xy = list(itertools.product(lx,ly)) #create a nice "table" of my lists
#that iterttools gives me something like
print xy
[(3.625, 41.435), (3.625, 42.435), (... , ..), ... ]
print xy[0][0]
print xy[0][1] #that works just fine, I can access the varios values of the tuple in the list
#down here is where the error occurs
#I basically try to access certain points in "lon"/"lat" with values from xy through `b` and `v`with that iteration. lon/lat are read earlier in the script
b = -1
v = 1
for l in xy:
b += 1
idx = N.where(lon==l[b][b])[0][0]
idy = N.where(lat==l[b][v])[0][0]
lan/lot are read earlier in the script. I am working with a netCDF file and this is the latitude/longitude,read into lan/lot.
Its an array, build with numpy.
Where is the mistake?
I tried to convert b and v with int() to integers, but that did not help.
The N.where is accessing through the value from xy a certain value on a grid with which I want to proceed. If you need more code or some plots, let me know please.

Your problem is that when you loop over xy, each value of l is a single element of your xy list, one of the tuples. The value of l in the first iteration of the loop is (3.625, 41.435), the second is (3.625, 42.435), and so on.
When you do l[b], you get 3.625. When you do l[b][b], you try to get the first element of 3.625, but that is a float, so it has no indexes. That gives you an error.
To put it another way, in the first iteration of the loop, l is the same as xy[0], so l[0] is the same as xy[0][0]. In the second iteration, l is the same as xy[1], so l[0] is the same as xy[1][0]. In the third iteration, l is equivalent to xy[2], and so on. So in the first iteration, l[0][0] is the same as xy[0][0][0], but there is no such thing so you get an error.
To get the first and second values of the tuple, using the indexing approach you could just do:
x = l[0]
y = l[1]
Or, in your case:
for l in xy:
idx = N.where(lon==l[0])[0][0]
idy = N.where(lat==l[1])[0][0]
However, the simplest solution would be to use what is called "tuple unpacking":
for x, y in xy:
idx = N.where(lon==x)[0][0]
idy = N.where(lat==y)[0][0]
This is equivalent to:
for l in xy:
x, y = l
idx = N.where(lon==x)[0][0]
idy = N.where(lat==y)[0][0]
which in turn is equivalent to:
for l in xy:
x = l[0]
y = l[1]
idx = N.where(lon==x)[0][0]
idy = N.where(lat==y)[0][0]

Python for() loop with math operators

Say I have a list of numbers such as:
my_list = [1, 17, 2]
And I wanted to add those together. I know I can use print(sum(my_list)). However I wanted to see if there was another way of doing so, so I tried the following:
b = len(my_list)
for m in range(my_list[0], my_list[b-1]):
m += m
print(m)
I am sure something like this should work, but I am obviously doing it wrong. The output of this is 2. After I tried:
result = 0
b = len(my_list)
for m in range(my_list[0], my_list[b-1]):
result = result + m
print(result)
This outputs 1.
Please explain what I am doing wrong and how I can correct it.

Since you are using range function defining range between 1 and 2. The only data generated in m is 1 hence result is 1.
In Python, you can iterate over the elements of a sequence directly:
m = [1, 17, 2]
res = 0
for i in m:
res += i
print res

First, you should put a correct range: 0..2 in your case (since your list items' indexes starts from 0 and has 2 items)
for i in range(0, b):
result = result + my_list[i];
Or if you prefer "for each" style you should itterate by list you are summing:
for m in my_list:
result = result + m;
Finally if you want to print a final sum only you should correct print indent:
for m in my_list:
result = result + m;
print(result) # <- mind indent
Wrapping up:
my_list = [1, 17, 2]
result = 0
for m in my_list:
result = result + m;
print(result)

from operator import add
my_list = [1, 17, 2]
result=reduce(add, my_list)

import functools
print(functools.reduce(lambda x,y: x+y, my_list))

try this
my_list = [1, 17, 2]
reduce(lambda x, y: x+y, my_list)

to get the values from my_list you can use this syntax:
for m in my_list:
print m
If you use range it will give you a range from 1 ( first value of your list ) to 2 (length of your list -1)
To add the values of your list you can try this code:
out = 0
for m in my_list:
out = out + m
print(out)