# can 1 + 1 be equal to 3 in python? [duplicate]

• Last Update :
• Techknowledgy :

Why is it that when I run the following code the answers are not 0?

```a = .1
d = .3

x = -a - a - a + d
y = a + a + a - d

print(f 'x is {x}')
print(f 'x is {y}')```

Instead I get the following:

```x is - 5.551115123125783e-17
y is 5.551115123125783e-17```

Suggestion : 2

In the list above, 2,3, and 1 are duplicates because the occurrence of these integers is more than one.,The code below shows how to find a duplicate in a list in Python:,If an integer or string or any items in a list are repeated more than one time, they are duplicates.,Here, the list (l1) has no duplicates. The values printed are the duplicates from list (l).

```l = [1, 2, 3, 4, 5, 2, 3, 4, 7, 9, 5]
l1 = []
for i in l:
if i not in l1:
l1.append(i)
else:
print(i, end = ' ')```

Suggestion : 3

Last Updated : 30 Jun, 2022

Examples :

```Input: list = [10, 20, 30, 20, 20, 30, 40, 50, -20, 60, 60, -20, -20]
Output: output_list = [20, 30, -20, 60]

Input: list = [-1, 1, -1, 8]
Output: output_list = [-1]```

`[20, 30, -20, 60]`

`[20, 30, -20, 60]`

```Counter({
1: 4,
2: 3,
5: 2,
9: 2,
3: 1,
4: 1,
6: 1,
7: 1,
8: 1
})[1, 2, 5, 9]```

`[1, 2, 5, 9]`

Suggestion : 4

When we run above program, the output will be:,When we run the program , the output will be:,When we run the program, it will output:,As you can see from the output both variables old_list and new_list shares the same id i.e 140673303268168.

### Example 1: Copy using = operator

```old_list = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 'a']
]
new_list = old_list

new_list[2][2] = 9

print('Old List:', old_list)
print('ID of Old List:', id(old_list))

print('New List:', new_list)
print('ID of New List:', id(new_list))```

When we run above program, the output will be:

```Old List: [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
ID of Old List: 140673303268168

New List: [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
ID of New List: 140673303268168```

We use the `copy` module of Python for shallow and deep copy operations. Suppose, you need to copy the compound list say x. For example:

```import copy
copy.copy(x)
copy.deepcopy(x)```

When we run the program , the output will be:

```Old list: [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
New list: [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]```

### Example 3: Adding [4, 4, 4] to old_list, using shallow copy

```import copy

old_list = [
[1, 1, 1],
[2, 2, 2],
[3, 3, 3]
]
new_list = copy.copy(old_list)

old_list.append([4, 4, 4])

print("Old list:", old_list)
print("New list:", new_list)```

Suggestion : 5

numbers[-1] is the last element of the list, numbers[-2] is the second to last, and numbers[-3] doesn’t exist.,Each time through the loop, the variable i is used as an index into the list, printing the i-eth element. This pattern of computation is called a list traversal.,It is common to use a loop variable as a list index.,A nested list is a list that appears as an element in another list. In this list, the element with index 3 is a nested list:

```[10, 20, 30, 40]
["spam", "bungee", "swallow"]```
`["hello", 2.0, 5, [10, 20]]`
```>>>
if []:
...print 'This is true.'
...
else:
...print 'This is false.'
...
This is false. >>>```
```>>> vocabulary = ["ameliorate", "castigate", "defenestrate"] >>>
numbers = [17, 123] >>>
empty = [] >>>
print vocabulary, numbers, empty['ameliorate', 'castigate', 'defenestrate'][17, 123][]```
```>>> print numbers[0]
17```
```>>> numbers[9-8]
123
>>> numbers[1.0]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: list indices must be integers```

Suggestion : 6

26. Write a Python program to compute the summation of the absolute difference of all distinct pairs in a given array (non-decreasing order). Go to the editor Sample array: [1, 2, 3] Then all the distinct pairs will be: 1 2 1 3 2 3 Click me to see the sample solution,25. Write a Python program to find the digits which are absent in a given mobile number. Go to the editor Click me to see the sample solution,18. Write a Python program to find the median among three given numbers. Go to the editor Click me to see the sample solution,29. Write a Python program to find common divisors between two numbers in a given pair. Go to the editor Click me to see the sample solution

The Any() Function:

```>>> arrival_hours = {
'Mon': 8.5,
'Tue': 8.75,
'Wed': 9,
'Thu': 8.5,
'Fri': 8.5
} >>>
arrival_checks = [x > 8.75
for x in arrival_hours.values()
] >>>
any(arrival_checks)
True```