I'm new to Python and I have this problem: I need to program a Python function that gives me back the sum of a list of numbers using a for loop. I just know the following: sum = 0
for x in [1,2,3,4,5]:
sum = sum + x
print(sum)
divibisan 10.6k11 gold badges39 silver badges57 bronze badges asked Apr 26, 2014 at 10:35
3 I think what you mean is how to encapsulate that for general use, e.g. in a function: def sum_list(l):
sum = 0
for x in l:
sum += x
return sum
Now you can apply this to any list. Examples: l = [1, 2, 3, 4, 5]
sum_list(l)
l = list(map(int, input("Enter numbers separated by spaces: ").split()))
sum_list(l)
But note that sum is already built in! answered Apr 26, 2014 at
10:42 jonrsharpejonrsharpe 109k25 gold badges214 silver badges394 bronze badges 0
l = [1,2,3,4,5]
sum = 0
for x in l:
sum = sum + x
And you can change l for any list you want. answered Apr 26, 2014 at 10:38 zbszbs 6614 silver badges16 bronze badges 0 x=[1,2,3,4,5]
sum=0
for s in range(0,len(x)):
sum=sum+x[s]
print sum
answered Apr 26, 2014 at 10:52 3 Sum in a for loop in Python #To sum in a for loop in Python: - Declare a new variable and set it to
0 . - Use a
for loop to iterate over a sequence of numbers. - Reassign the variable to its value plus the current number.
Copied! my_list = [2, 4, 6, 8]
# ✅ sum using a for loop
total = 0
for num in my_list:
total += num
print(total) # 👉️ 20
# ----------------------
# ✅ sum numbers in range using a for loop
total_2 = 0
for num in range(1, 5):
total_2 += num
print(total_2) # 👉️ 10
print(list(range(1, 5))) # 👉️ [1, 2, 3, 4]
# ----------------------
# ✅ sum numbers taken from user input using a for loop
# 👇️ user enters 1 2 3 4
user_input = input('Enter space-separated numbers:')
my_list = list(map(int, user_input.split()))
print(my_list) # 👉️ [1, 2, 3, 4]
total_3 = 0
for num in my_list:
total_3 += num
print(total_3) # 👉️ 10
We used a for loop to sum the
numbers in a list. The first step is to declare a new variable and initialize it to 0 . On each iteration, we use the += operator to reassign the variable to its current value plus the current number. The following 2 lines of code achieve the same result: total += num total = total + num
Here is an example that uses the longer reassignment syntax. Copied! my_list = [2, 4, 6, 8]
total = 0
for num in my_list:
total = total + num
print(total) # 👉️ 20
If you need to add the numbers in a certain range using
a for loop, create the range with the range() class. Copied! total_2 = 0
for num in range(1, 5):
total_2 += num
print(total_2) # 👉️ 10
print(list(range(1, 5))) # 👉️ [1, 2, 3, 4]
The range class is commonly used for looping a specific number of times in for loops and takes the following parameters:
Name | Description |
---|
start
| An integer representing the start of the range (defaults to 0 )
| stop
| Go up to, but not including the provided integer
| step
| Range will consist of every N numbers from start to stop (defaults to 1 )
|
If you need to sum numbers taken from user input in a for loop, use the input() function. Copied! # 👇️ user enters 1 2 3 4
user_input = input('Enter space-separated numbers:')
my_list = list(map(int, user_input.split()))
print(my_list) # 👉️ [1, 2, 3, 4]
total_3 = 0
for num in my_list:
total_3 += num
print(total_3) # 👉️ 10
The input function takes an optional prompt argument and writes it to standard output without a trailing newline. The input() function is guaranteed to return a string even if the user enters a number.
We ued the str.split() function to split the string on each space. The str.split() method splits the string into a list of substrings using a delimiter. The method takes the following 2 parameters:
Name | Description |
---|
separator
| Split the string into substrings on each occurrence of the separator
| maxsplit
| At most maxsplit splits are done (optional)
|
If the separator is not found in the string, a list containing only 1 element is returned. We used a whitespace separator in the example, but you use any other separator that suits your use case. Here is an example that splits the user-provided string on each comma. Copied! # 👇️ user enters 1,2,3,4
user_input = input('Enter comma-separated numbers:')
my_list = list(map(int, user_input.split(',')))
print(my_list) # 👉️ [1, 2, 3, 4]
total_3 = 0
for num in my_list:
total_3 += num
print(total_3) # 👉️ 10
After splitting the string, we get a list of strings, so we used the map() function to convert each string in the list to an integer.
Copied! # 👇️ user enters 1,2,3,4
user_input = input('Enter comma-separated numbers:')
# 👇️ ['1', '2', '3', '4']
print(user_input.split(','))
The map() function takes a function and an iterable as arguments and calls the function with each item of the iterable. The map() function passes each string to the int() class and converts it to an integer.
How do you add numbers in a list in Python?
Use append() function to add numbers in a list Python.
How do you add numbers in a list in a while loop?
Simple use if statement with a while loop to calculate the Sum of n numbers in Python. Taken a number input from the user and stored it in a variable num. Use a while loop to iterate until num gets zero. In every iteration, add the num to sum, and the value of num is decreased by 1.
How do you add numbers to a series in Python?
How to Add Two Numbers in Python. ❮ Previous Next ❯. Example. x = 5. y = 10. print(x + y) Try it Yourself ». Example. x = input("Type a number: ") y = input("Type another number: ") sum = int(x) + int(y) print("The sum is: ", sum) Try it Yourself ».
How do you sum elements in a list?
Sum Of Elements In A List Using The sum() Function. Python also provides us with an inbuilt sum() function to calculate the sum of the elements in any collection object. The sum() function accepts an iterable object such as list, tuple, or set and returns the sum of the elements in the object.
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