Python ing list instance analysis-Python tutorial

This article mainly introduces the python ing list. The example analyzes how to use the python ing list to traverse and compute each element. if you need it, refer to the following example to describe the python ing list. Share it with you for your reference. The specific analysis is as follows:

List ING is a very useful method. by applying a function to each element in the list to convert data, you can use a policy or method to traverse and compute each element.

For example:

The code is as follows:

Params = {"server": "mpilgrim ",\
"Database": "master ",\
"Uid": "sa ",\
"Pwd": "secret "\
}
Print ["% s = % s" % (k, params [k]) for k in params. keys ()]
Print ';'. join (["% s = % s" % (k, params [k]) for k in params. keys ()])

The returned result is:

The code is as follows:

['Uid = sa ', 'pwd = secret', 'database = master', 'server = mpilgrim']

We can also improve the conversion of tuples into strings and use the join function method.

The code is as follows:

'Uid = sa; pwd = secret; database = master; server = mpilgrim'

(The join function is used not only for tuples but also for lists. the function is string-based)
In contrast to join, split converts a string to a metagroup.
See the following applications.

The code is as follows:

Str = 'server = mpilgrim; uid = sa; database = master; pwd = secret'>>> Str. split (';')
['Server = mpilgrim', 'uid = sa ', 'database = master', 'pwd = secret']
>>> Str. split (';', 1)
['Server = mpilgrim', 'uid = sa; database = master; pwd = secret ']
>>> Str. split (';', 2)
['Server = mpilgrim', 'uid = sa ', 'database = master; pwd = secret']

List ING case:

The code is as follows:

>>>> Li = [1, 9, 8, 4]
>>> [Elem * 2 for elem in li] 1
[2, 18, 16, 8]
>>> Li
[1, 9, 8, 4]

I hope this article will help you with Python programming.