What is :- 1 in Python?

Reverse the order of a string in Python

Use the [::-1] to reverse the order of a string in Python −

What does [:- 1 mean in Python slicing?

So [::-1] means from 1st element to last element in steps of 1 in reverse order.

What does [:- 1 index in Python?

The colons are separators. Rather than providing a "beginning" and an "end" index, it's telling Python to skip by every -1 objects in the array. It's effectively reversing the array.

What is the difference between [:- 1 and 1 in Python?

The main difference between the 1 and 1. is in their type and type of the result of any equation that include float number in python will be float. That include addition subtraction multiplication exponents and even the integer division as if one operand is float answer will be of type float.

What is [:- 4 in Python?

What does the [-4:] means? The some_list[-n] syntax gets the nth-to-last element. So some_list[-4] gets the last four elements.

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What is [- 3 :] in Python?

[3:] is a subscript meaning to refers to indices. As shown here, it is known as a slice.

What is 2 :] in Python?

The [2: ] is slice notation, and since that's being performed on a str , it means that you're retrieving all of the characters of the string starting at index 2. In this case, that's getting rid of 0b .

What is the difference between 0 :] and 0 :- 1 in Python?

So, what is the difference between the two exactly? The is the same as normal Python slicing: candidates[0] is the first element (in this case, the first row); candidates[0:1] is a collection of the first one elements (in this case, a 2D array containing only the first row).

What does I += 1 mean?

The solution means to say that there is no difference, ++i has the same meaning as (i += 1) no matter what i happens to be and no matter the context of the expression.

Is it += or =+ in Python?

The plus-equals operator += provides a convenient way to add a value to an existing variable and assign the new value back to the same variable.

What does [- 1 :] do in Python?

For negative indexing, to display the 1st element to last element in steps of 1 in reverse order, we use the [::-1]. The [::-1] reverses the order.

What is [- 1 negative indexing in Python?

Negative Indexing is used to in Python to begin slicing from the end of the string i.e. the last. Slicing in Python gets a sub-string from a string. The slicing range is set as parameters i.e. start, stop and step.

When slicing in Python What does the 2 in [:: 2 specify?

string[2::2] reads “start index of two, default stop index, step size is two—take every second element starting from index 2“.

What is list [:] in Python?

A list is a data structure in Python that is a mutable, or changeable, ordered sequence of elements. Each element or value that is inside of a list is called an item. Just as strings are defined as characters between quotes, lists are defined by having values between square brackets [ ] .

What does [: 0 mean in Python?

It acts as an indicator in the format method that if you want it to be replaced by the first parameter(index zero) of format. Example : print(42+261={0}.format(303))

What does colon 1 mean in Python?

A colon on the left side of an index means everything before, but not including, the index. example[:2] [1, True] And if we use a negative index, it means get elements from the end, going backwards. # last element example[-1] # everything except the last two elements example[:-2]

Is i ++ the same as i 1?

These two are exactly the same. It's just two different ways of writing the same thing. i++ is just a shortcut for i += 1 , which itself is a shortcut for i = i + 1 .

What is the output of i 1?

The output for all the print functions is the same that is 1.

Is True == 1 in Python?

Because True is equal to 1 and False is equal to 0 , adding Booleans together is a quick way to count the number of True values.

Why do we use == in Python?

The == operator helps us compare the equality of objects. The is operator helps us check whether different variables point towards a similar object in the memory. We use the == operator in Python when the values of both the operands are very much equal. Thus, the condition would become true here.

Is 0.0 false in Python?

Python assigns boolean values to values of other types. For numerical types like integers and floating-points, zero values are false and non-zero values are true.

What does ::= mean in Python?

The walrus operator is denoted := , and introduced in Python 3.8. This operator is used for and only for the assignment of variables within another expression. At the very least, it can save one or more lines of code, and at most, it can dramatically speed up the processing of large data.

What is Python 2 vs 3 <>?

Python 3 has an easier syntax compared to Python 2. A lot of libraries of Python 2 are not forward compatible. A lot of libraries are created in Python 3 to be strictly used with Python 3. Python 2 is no longer in use since 2020.

How to use += in Python?

In Python, the new line character “\n” is used to create a new line. When inserted in a string all the characters after the character are added to a new line. Essentially the occurrence of the “\n” indicates that the line ends here and the remaining characters would be displayed in a new line.