How can Python tell if a slice doesn t exist?

Slices can have two colons in three segments.

Similar to for loops in other languages.

For example, list[a:b:c].

Returns the list from the beginning of the A index to the end of B, and takes the generated list every C element.

A, B, and C can be left blank.

0 to 2, it's fine.

I've also thought about this question, why is it designed like this?

My analysis is very simple, if we are doing a continuous slice operation of a set, if "before packing" and "after", there will be a calculation for the starting value of the next slice, because the last item is already included in the result of the previous slice operation, so we have to dynamically calculate the starting position of the next one plus 1, otherwise it will cause repeated slicing.

If you don't do it, the index at the end of the previous time will be sliced directly as the starting position of the next time, so that when a large number of operations are performed on the data, the huge computational operations will be reduced, thus saving performance.

Slices can have two colons in three segments.

Similar to for loops in other languages.

For example, list[a:b:c].

Return the list of a index from the beginning to the end of b, and take a generated list a, b, and c every c element can be left blank.

0 to 2, it's fine.

Slicing operation: It is very easy to intercept list and tuple elements.

l[0:3],l[:3] truncate the first 3 elements.

l[1:3] Intercept 2 elements from 1.

l[-1] takes the penultimate element out.

l[-10] takes the last 10 digits.

l[10:20] Take the first 11-20 numbers.

l[:10:2] take the first 10 numbers, take one for every two l[::5] take all numbers, take one for every 5.

l[:] copy a list as is

tuple, strings can also be sliced.

A list of strings.

Tuple dictionaries. Slicing is just a name, the so-called slicing, is equivalent to cutting a slice of a loaf of bread, for example, we want to take the 2nd to 5th characters in the s string, it can also be called a slice.

The python program that slices the elements in the list according to your requirements according to the specified characters is as follows:

#!/usr/bin/python

b=a=["Ahh", "Uh, uh, uh. Goose goose goose goose hungry"]for i in range(0,len(a)):

b=b+a[i].split("。")

print(b)

I don't understand what the output you want is the same input and output.

It's okay to do it all over the world. Another suggestion""The advantage of this method is that it can distinguish between a file and a directory. Sometimes this distinction makes sense.

You can use this method to directly determine whether a file exists.

**As follows: >> import os

> 'c:\')

false>> returns true if exists, and false if non-existent. Very convenient, hope it helps you

Take one or more elements in the list.