a[start:stop] # items start through stop-1
a[start:] # items start through the rest of the array
a[:stop] # items from the beginning through stop-1
a[:] # a copy of the whole array
Example:
>>> a = [1, 2, 3, 4, 5, 6, 7, 8]
>>> a[1:4]
[2, 3, 4]
thislist = ["1.apple", "2.banana", "3.cherry", "4.orange", "5.kiwi", "6.melon", "7.mango"]
# thislist[starting index(including) : end index(not including):step]
print(thislist[:]) #Output: ['1.apple', '2.banana', '3.cherry', '4.orange', '5.kiwi', '6.melon', '7.mango']
print(thislist[1:]) #Output: ['2.banana', '3.cherry', '4.orange', '5.kiwi', '6.melon', '7.mango']
print(thislist[:5]) #Output: ['1.apple', '2.banana', '3.cherry', '4.orange', '5.kiwi']
print(thislist[2:5]) #Output: ['3.cherry', '4.orange', '5.kiwi']
print(thislist[::3]) #Output: ['1.apple', '4.orange', '7.mango']
print(thislist[1::2]) #Output: ['2.banana', '4.orange', '6.melon']
print(thislist[1:6:3]) #Output: ['2.banana', '5.kiwi']
#slicing arrays:
#generic sampling is done by
#arr[start:end] -> where start is the starting index and end is ending idx
>>> import numpy as np
>>> arr = np.array([1,2,3,4,5])
>>> print(arr[1:5]) #starting idx 1 to ending index 4
[2 3 4 5]#it will print from starting idx to ending idx-1
#if you leave the ending index blank it will print all
#from the starting index till end
>>> arr = np.array([2,6,1,7,5])
>>> print(arr[3:])
[7 5]
>>> print(arr[:3]) #if you leave the starting index blank it will print from 0 index to the ending idx-1
[2 6 1]
>>> print(arr[:])
[2 6 1 7 5]
#leaving both the index open will print the entire array.
##########STEP slicing########
#if you want to traverse by taking steps more than 1
#we use step slicing in that case
#syntax for step slicing is : arr[start:end:step]
>>> arr = np.array([2,6,1,7,5,10,43,21,100,29])
>>> print(arr[1:8:2])#we have taken steps of two
[ 6 7 10 21]