1. The sequence for storing values of a plurality of contiguous memory space, according to a certain order
1) The index
1 to n-1
-n to -1
2) Slice
sname[start:end:step]
print (nba [2: 4]) # 3-5 to obtain the first element
print (nba [2: 4: 5] # of 3/5/6 element obtained
3) sequences are added
a = [21,33,44]
b=[1,2,4]
print (whether b)
4) Multiplication
print(b*3]
Output: [1,2,4,1,2,4,1,2,4]
emptylist = [none]*5
print(emptylist)
[none,none,none,none,none]
5) checks whether an element is a member of the sequence
value in sequence
print("1" in b)
Showing results True
print("1" not in b)
Showing results False
6) Calculate the length of the sequence, a maximum value, a minimum value
print ( "sequence length:", len (b))
print ( "Maxima:", max (b))
print ( "minimum sequence:", min (b))
list () is converted into a sequence listing
str () sequence into a string
sum () sums
sorted () to sort the elements
the reversed () element in reverse sequence
emumetate () while the output element and index values
2. [within] a list, in order, divided
Content, the content of any real numbers, integers, strings, lists, and the like can be placed in the tuple list. List, may be different types of elements, there is no relationship between them.
listname =[element1 , element2 , element2 , element3,...]
emptylist = [] # Empty list
Create a list of values, list (range (10,20,2)) -> [10,12,14,16,18]
Delete List del #del emptylist
3. traverse the list
for item in listname:
Output item #
for index,item in enumerate(listname):
Output index and item #
4. Add the elements
listname.append (obj) #append element ratio command to add a "+" is more efficient, as this
listname.extend (seq) # a list of all elements added to the list to another
Modify elements direct assignment verse [-1] = "line on the blue sky egret"
Removing elements del verse [-1] # deleted according to element index
vrese.remove ( "Bull") # Remove element values according to
value = "Bull"
if verse.cont (value)> 0: # ensure that the elements present in the list
verse.remove(value)
5. statistical and computing
listname.count (obj) #obj appear in the list cis
listname.index (obj) #obj index values in the list
sum (listname [, start]) # summation, start statistical results indicate the start index.
6. Sort
sort(）
listname.sort(key=None,reverse=False）
listname: To sort the list represents
key: Comparison of key, key = str.lower, showing a case-insensitive
reverse: True descending, False ascending
sorted () # built-in functions will not change the original sequence
List comprehensions:
1. import dandom
randomnumber =[random.randint(10,100) for i in range(10)]
2.
price=[1,2,3]
sale=[int(x*0.5) for x in price]
3. sele= [x for x in price if x>4]
6. The two-dimensional list
arr=[ ]
for i in range(4):
arr.append([])
for j in range(5):
arr[i].append(j)
List comprehensions
arr =[[j for j in range(5)] for i in range(4)]