Python data type --- list 3, python Data Type

Python data type --- list 3, python Data Type

1. determine whether an element exists in the list: "in" Usage

List = ['frank', 99, 'is ', 78, 4, 'smart'] print (99 in list) print (9 in list) # running result TrueFalse

2. Statistics on the number of elements: count

>>> name = ['3',4,45,4343,34,56,6,7,5,3,9]>>> name.count(9)1>>> name.count(3)1>>>

3. Element Location index: index (
L. index (value, [start, [stop])-> integer -- return first index of value.
Raises ValueError if the value is not present .)

List = ['frank', 99, 'is', 78, 9,939, 4, 4, 'smart', 9] print (99 in list) print (9 in list) # count use num_of_ele = list. count (9) # Use posistion_of_ele = list for index. index (9) print ("[% s] 9 in list, posistion is [% s]" % (num_of_ele, posistion_of_ele) # Test Result TrueTrue [2] 9 in list, posistion is [8]

4. List Extension: extend

Name = ["frank", "Malon", "Lee"] name2 = ["Andy", "Troy"] name. extend (name2) print (name) print (name2) # Run the result ['frank', 'malon', 'Lee ', 'andy ', 'troy'] ['andy ', 'troy']

5. copy the list: copy # L. copy ()-> list -- a shallow copy of L only for superficial copying

Name = ['Alex ', 'rain', 'erik', ['A', 'B', 'C'], 'frank'] name3 = name. copy () print ("Test 1") print (name) print (name3) print ("Test 2") name [0] = 'Alex 'print (name) print (name3) print ("Test 3") name [3] [0] = 'aaaaa' print (name) print (name3) print ("Test 4 ") name3 [3] [2] = 'cccccc' print (name) print (name3) # Test Result 1 ['Alex ', 'rain', 'erik ', ['A', 'B', 'C'], 'frank'] ['Alex ', 'rain', 'erik', ['A', 'B ', 'C'], 'frank'] Test 2 ['Alex ', 'rain', 'erik', ['A', 'B', 'C'], 'frank'] ['Alex ', 'rain', 'erik', ['A', 'B', 'C'], 'frank'] Test 3 ['Alex ', 'rain', 'erik', ['aaaaaaa', 'B', 'C'], 'frank'] ['Alex ', 'rain', 'erik', ['aaaaa', 'B', 'C'], 'frank'] Test 4 ['Alex ', 'rain', 'erik', ['aaaaaaa', 'B', 'cccccccccccc'], 'Frank '] ['Alex', 'rain', 'erik ', ['aaaaa',' B ', 'cccccccc'], 'frank']

6. List copy --- deepcopy (import copy)

Import copyname = ['Alex ', 'rain', 'erik', ['A', 'B', 'C'], 'frank'] name3 = name. copy () name4 = copy. deepcopy (name) print ("Test 1") print (name) print (name3) print (name4) name [3] [1] = 'aaaaaaaaa' print ("Test 2") print (name) print (name3) print (name4) # Test Result 1 ['Alex ', 'rain', 'erik ', ['A',' B ', 'C'], 'frank'] ['Alex', 'rain', 'erik ', ['A', 'B', 'C'], 'frank'] ['Alex ', 'rain', 'erik', ['A', 'B ', 'C'], 'frank'] Test 2 ['Alex ', 'rain', 'erik', ['A', 'aaaaaaa', 'C'], 'Frank '] ['Alex', 'rain', 'erik ', ['A', 'aaaaaaaaa', 'C'], 'frank'] ['Alex ', 'rain', 'erik ', ['A',' B ', 'C'], 'frank']