# Starting up with Python – Part3

Moving on to the part 3 of my article on Learning Python, I have now reached Sequences and List. It’s indeed a vast python world. Previous articles are as follows:

5. Sequences and List

There are six sequence types: strings, Unicode strings, lists, tuples, buffers, and xrange objects. To create a list, we first give the list a name. For example family = [‘mom’, ‘dad’, ‘sister’, ‘brother’, ‘cat’] Each element within the list is associated with a number starting by 0. It is also counted backward with negative numbers.

```>>> family = ['mom', 'dad', 'sister', 'brother', 'cat']
>>> family[0]
'mom'
>>> family[1]
>>> family [-5]
'mom'
>>> family [-1]
'cat'```

You can also extract characters from a string as c is referenced as number 2

```>> 'hackers' [2]
'c'```

6. Slicing

Lets now extract a slice of a sequence. You can slice information from a sequence in a backward sequence too. When slicing you need two values. If no values are given, it gives you the whole sequence.

```> example = [0,1,2,3,4,5,6,7,8,9]
>>> example [4:8]
[4, 5, 6, 7]
>>> example [4:9]
[4, 5, 6, 7, 8]
>>> example [4:10]
[4, 5, 6, 7, 8, 9]
>>> example [-5:]
[5, 6, 7, 8, 9]```
```>> example [:]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9```

You can also extract information using 3 values that is the starting number, the ending number and the optional number [How many numbers you want to skip before getting to the last one] example [1:8:2]

```> example [1:8:2]
[1, 3, 5, 7]```
```>>> example [::-2]
[9, 7, 5, 3, 1]```

7.Editing

Sequences, unlike, strings can also be concatenated. By creating two sequences and using the + sign in between to get it concatenated.

```>> [7,4,5]+[4,6,5]
[7, 4, 5, 4, 6, 5]```

You can also multiply strings and sequences

```>> 'HackersMauritius' * 2
'HackersMauritiusHackersMauritius'```
```>> [100]* 2
[100, 100]```

You can also check for characters in a name example. Is there the letter Z in hackersMauritius ?

```name ='HackersMauritius'
>>> 'z' in name
False
>>> 'a' in name
True```

I can also check for elements in a sequence

```> family = ['mom', 'dad', 'sister', 'brother', 'cat']
>>> 'dog' in family
False
>>> 'cat' in family
True```
Nitin J Mutkawoa https://tunnelix.com

Blogger at tunnelix.com | Founding member of cyberstorm.mu | An Aficionado Journey in Opensource & Linux – And now It's a NASDAQ touch!