You can just use sum(people$Weight). sum sums up a vector, and people$Weight retrieves the weight column from your data frame. Note – you can get built-in help by using ?sum, ?colSums, etc. (by the way, colSums will give you the sum for each column).
You can first select by iloc and then sum: df[‘Fruit Total’]= df.iloc[:, -4:-1].sum(axis=1) print (df) Apples Bananas Grapes Kiwis Fruit Total 0 2.0 3.0 NaN 1.0 5.0 1 1.0 3.0 7.0 NaN 11.0 2 NaN NaN 2.0 3.0 2.0 For sum all columns use: df[‘Fruit Total’]= df.sum(axis=1)
Both lines you posted are fine, but you can do it purely in integers, and it will be the most efficient: def sum_digits(n): s = 0 while n: s += n % 10 n //= 10 return s or with divmod: def sum_digits2(n): s = 0 while n: n, remainder = divmod(n, 10) s += … Read more
You can first make a conditional selection, and sum up the results of the selection using the sum function. >> df = pd.DataFrame({‘a’: [1, 2, 3]}) >> df[df.a > 1].sum() a 5 dtype: int64 Having more than one condition: >> df[(df.a > 1) & (df.a < 3)].sum() a 2 dtype: int64 If you want to … Read more
Use a generator expression: sum(c.a for c in c_list)
If you’re doing much numerical work with arrays like this, I’d suggest numpy, which comes with a cumulative sum function cumsum: import numpy as np a = [4,6,12] np.cumsum(a) #array([4, 10, 22]) Numpy is often faster than pure python for this kind of thing, see in comparison to @Ashwini’s accumu: In [136]: timeit list(accumu(range(1000))) 10000 … Read more
You can use array_walk_recursive() to get a general-case solution for your problem (the one when each inner array can possibly have unique keys). $final = array(); array_walk_recursive($input, function($item, $key) use (&$final){ $final[$key] = isset($final[$key]) ? $item + $final[$key] : $item; }); Example with array_walk_recursive() for the general case Also, since PHP 5.5 you can use … Read more
The zip function is useful here, used with a list comprehension. [x + y for x, y in zip(first, second)] If you have a list of lists (instead of just two lists): lists_of_lists = [[1, 2, 3], [4, 5, 6]] [sum(x) for x in zip(*lists_of_lists)] # -> [5, 7, 9]
Use COALESCE to avoid that outcome. SELECT COALESCE(SUM(column),0) FROM table WHERE … To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0 More Information: Given three tables (one with all numbers, one with all nulls, and one with a mixture): SQL Fiddle MySQL 5.5.32 Schema Setup: CREATE TABLE foo ( id INT NOT NULL … Read more
In java-8 you can use streams: int[] a = {10,20,30,40,50}; int sum = IntStream.of(a).sum(); System.out.println(“The sum is ” + sum); Output: The sum is 150. It’s in the package java.util.stream import java.util.stream.*;