I assume you want to see decimals in the result, even though your input values are integers. By default, Python does integer division: it discards the remainder. To divide things through all the way, we need to use floating-point numbers. Fortunately, dividing an int by a float will produce a float, so we just use 2.0 for our divisor instead of ...

You could also use transform() on column Number after group by. This operation will calculate the total number in one group with function sum, the result is a series with the same index as original dataframe. df['Number'] = df.groupby(['Fruit', 'Name'])['Number'].transform('sum') df = df.drop_duplicates(subset=['Fruit', 'Name']).drop('Date', 1)

Dec 13, 2024 · As explained on Python's documentation, the sum function will sum the start value (2nd argument) with the items from an iterable data structure (1st argument). And, as mentioned on the comments, a dict by default is iterable over its keys.

Oct 7, 2017 · In Python 2 you can avoid making a temporary copy of all the values by using the itervalues() dictionary method, which returns an iterator of the dictionary's keys: sum(d.itervalues()) In Python 3 you can just use d.values() because that method was changed to do that (and itervalues() was removed since it was no longer needed).

Apr 26, 2018 · I'm new to python and I started learning to execute function. And I started adding numbers but I could only sum two numbers and if I wanted to sum more, it would require I edit the program. Here's my code. def sum(num1,num2): return num1+num2 a=5 b=7 c=sum(a,b) print (c)

For a single column, we can sum in two ways: use Python's built-in sum() function and use pandas' sum() method. It should be noted that pandas' method is optimized and much faster than Python's sum(). For example, to sum values in a column with 1mil rows, pandas' sum method is ~160 times faster than Python's built-in sum() function.

Aug 28, 2012 · def V(theta, N): return sum(a0*(cos(i*theta)) for i in range(1, N + 1)) Note that you have to pass theta and N to the function. Also note that we are using N + 1 to make sure N is included (as range iterates over the values until, but not including, the last value).

The missing piece as to why str is not allowed for sum is that many, many people were trying to use sum for strings, and not many use sum for lists and tuples and other O(n**2) data structures. The trap is that sum works just fine for short lists of strings, but then gets put in production where the lists can be huge, and the performance slows ...

This is a terrible idea. The general idea of emulate sum() using a list comprehension goes against the whole purpose of a list comprehension. You should not use a list comprehension in this case. Python 2.5 / 2.6 Hack. In Python 2.5 / 2.6 You could use vars()['_[1]'] to refer to the list

Aug 23, 2012 · def problem1_3(x): my_sum=0 count = 1 while count<=x: my_sum=my_sum+count count = count+1 return my_sum print(my_sum) Lets assume you set x = 3 The way I believe python interprets this is as follows: set my_sum = 0 and count = 1 1. First iteration with the while loop: 1 <= 3 : True so my_sum = 0+1 plus count increases by 1 and now count = 2 The ...