Examples of how to select nth element in a list with python:
Create a list
Let's first create a list with python:
mylist = ['A', 'B', 'C', 'D', 'E', 'F']
Note that a list is 0 based indexing.
index | element |
---|---|
0 | A |
1 | B |
2 | C |
3 | D |
4 | E |
5 | F |
Check the following link to learn more about different data structures in python.
Select the first element of a list
To select the first element of a list
mylist[0]
returns here
'A'
Select the last element of a list
To select the last element of a list
mylist[-1]
returns here
'F'
Select nth element of a list
To select nth element of a list
mylist[4]
returns here
'E'
However
mylist[6]
will returns the following error message
IndexError: list index out of range
since the list contains only 6 element.
To avoid that
index = 6
if index < len(mylist):
print(mylist[index])
else:
print('Warning: list index out of range')
or
try:
mylist[index]
except:
pass
Find index of a given element
Note to find the index of a given element
mylist.index('D')
returns
3
Note: To check if an element is in a list:
'D' in mylist
returns
True
while
'G' in mylist
returns
False
Loop through a list and print element with associated index
To loop through a list and print element with associated index, a solution is to use enumerate()
for i,e in enumerate(mylist):
print(i,e)
returns here
0 A
1 B
2 C
3 D
4 E
5 F