Python Learning list Notes

Python Learning list Notes

The list is the most frequently used data type in Python;

Support for characters, numbers, strings can even contain lists (so-called nesting)

1. Definition:

List = [1,3,4,5, ' goog ', ' well ', 777]

2. Increase from the last column:

List.append ("Your is good!")

Show:

Direct input: List

Display: [1, 3, 4, 5, ' goog ', ' well ', 777, ' Your is good! ']

3. Add a column from the middle such as:

Use: Insert function:

Here's how to use it:

>>> List.insert (8, ' Liwen ')

>>> List

[1, 3, 4, 5, ' goog ', ' Liwen ', ' well ', ' Liwen ', ' Liwen ', 777, ' Your is good! ']

4. Delete one:

Using the Del

Such as:

>>> List

[1, 3, 4, 5, ' goog ', ' Liwen ', ' well ', ' Liwen ', ' Liwen ', 777, ' Your is good! ']

>>> del list[1] #删除下标为第一个的值

>>> List

[1, 4, 5, ' goog ', ' Liwen ', ' well ', ' Liwen ', ' Liwen ', 777, ' Your is good! ']

5. Traverse All values:

list = [1, 4, 5, ' goog ', ' Liwen ', ' well ', ' Liwen ', ' Liwen ', 777, ' Your is good! ']

Use for loop traversal:

For I in list:

Print I

6. View list length using the Len function

list = [1, 4, 5, ' goog ', ' Liwen ', ' well ', ' Liwen ', ' Liwen ', 777, ' Your is good! ']

Print Len (list)

print ' ===================== '

A = ' ddddddddddddddddddd '

Print Len (a)

10

=====================

19

=====================

7, Calculation: Statistics 5 appeared several times:

c = [1,3,4,5,5,5,5,5,4,5,4,6,9]

ncount = 0

For I in C:

if i = = 5:

ncount = ncount + 1

Print Ncount

Results:

6

==========ncount===========

Even and odd:

Range (1,101,2) odd

[1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99]

Range (2,101,2) even

[2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64 , 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100]

Add:

1.

#!/usr/bin/env python

#-*-Coding:utf-8-*-

if __name__ = = ' __main__ ':

list = [' html ', ' JS ', ' css ', ' python ']

# method 1

Print U ' Traversal list Method 1: '

For I in list:

Print (U "ordinal:%s Value:%s"% (List.index (i) + 1, i))

Print U ' \ n Traverse list Method 2: '

# method 2

For I in range (len (list)):

Print (U "ordinal:%s Value:%s"% (i + 1, list[i]))

# Method 3

Print U ' \ n Traverse list Method 3: '

For I, Val in enumerate (list):

Print (U "ordinal:%s Value:%s"% (i + 1, val))

# Method 3

Print U ' \ n Traverse the list Method 3 (set the start of the traverse starting at the beginning, changing only the starting sequence): '

For I, Val in enumerate (list, 2):

Print (U "ordinal:%s Value:%s"% (i + 1, val))

Python Learning list Notes