Python list and tuple operations

 

  #list (the combination of a set of ordered data is a list)


#create a list #empty list

var = list() #var = []

print(var,type(var)) #list with multiple elements

var = ['wind ','Water','Feng Shui'] print(var,type(var)) #Basic operation

var = ['Earth','Fire','Earth Fire'] #Access elements in the list

print(var[-2 ]) #Modify element

var[1] = 'Water'

print(var) #Delete element

del var[1] print(var) #Add element (cannot be added) #Sequence


operation

listvar1 = ['Hu Yifei','Zeng Xiaoxian', 'Lu Zhanbo'] listvar2 = ['Lin Wanyu','Chen Meijia','Lu Ziqiao','Guangu Magic']

#Addition result = listvar1 + listvar2 print(result)

#Multiplication result = listvar1 * 2

print(result ) #shard #result = listvar2[:3] #result = listvar2[1:] #result = listvar2[1:3] #result = listvar2[:] ​​#print(result) #member


detection

result = 'Lisa Rong' in listvar2 print(result) result = 'Lisa Rong' not in listvar2 print(result) #Sequence function #len() Detect the number of elements in the list

var = ['Zhang San','Li Si ','Wang Wu','Zhao Liu'] result = len(var) print(result) #max() Get the maximum value

result = max([12,23,34,45,21,32,43,54] ) print(result) #min() get the minimum value

result = min([12,23,34,45,21,32,43,54]) print(result) #traverse the list


#for...in

var = [ 'Red','Orange','Yellow','Green','Blue','Blue','Purple'] for i in var: print(i) #while traverse

i = 0 while i < len(var ): print(var[i]) i += 1


#Multilayer list traversal

var = [ ['Xiaohe','black'], ['Xiaobai','white'], ['Xiao Cai', 'color'] ] #Equal-length secondary list

for i,j in var: print(i,j) #Equal-length or unequal-length lists can be traversed

for i in var: #print(i)

    for j in i: print(j) #List comprehension

var = ['Duan Yu','Xuzhu','Qiao Feng','Mu Wanqing','Zhong Linger'] #The most basic list comprehension

result = ['@'+i+'@' for i in var] print(result) #Write list 1-10, use list comprehension to get the list of each number*3 in the current list

var = [1,2,3 ,4,5,6,7,8,9,10] result = [i * 3 for i in var] print(result) #List comprehension with condition

var = [1,2,3,4, 5,6,7,8,9,10] result = [a for a in var if a % 2 == 0] print(result) #declare a list of multiple names, use derivation to get all three characters

var = ['Duan Yu','Xuzhu','Qiao Feng','Mu Wanqing','Zhong Linger'] result = [n for n in var if len(n) == 3] print(result) #Multi-loop list

comprehension sizes = [37,38,39,40,41] colors = ['yellow','cyan','pink','purple'] result = [str(s) +'-'+ c for s in sizes for c in colors] print(result) #4 male group, 5 female group, meet each other once

men = ['male 1', 'male 2', 'male 3', 'male 4' ] women = ['Female 1','Female 2','Female 3','Female 4','Female 5'] result = [m +'-' + w for m in men for w in women] print(result) #Multi-loop list comprehension with judgment conditions

men = ['Male1','Male2','Male3','Male4'] women = ['Male1','Male2','Male3','Male4'] result = [m +'-'+ w for m in men for w in women if men.index(m) == women.index(w)] print(result) #append() Adding elements to the end of the list directly modifies the metalist

var = ['a','b','c','d'] print(var) var.append('e') print(var) #insert() add an element before the specified position in the list

var = ['a ','b','c','d'] print(var) var.insert(2,'g') print(var) #pop() delete the element at the specified position in the list

var = ['a', 'b','c','d'] print(var) result = var.pop(0) print(var,result) #remove() remove the element with the specified value in the list

var = ['a','b ','c','d'] print(var) result = var.remove('c') print(var,result) #clear() clear list

var = ['a',' b','c'] print(var,id(var)) var.clear() print(var,id(var)) #copy() copy list

var = ['a','b','c' ,'d'] print(var,id(var)) newvar = var.copy() print(newvar,id(newvar)) #count() Count the number of occurrences of an element in a list

var = [2,3,4,3,4,5,6,7,8,5,4,6,7,8] result = var.count(5) print(result) #excend() converts a list merge into another list

var1 = ['xs','dc','yyh','wzj'] var2 = ['dsn','lss','cyy','lrs'] var1.extend(var2) print(var1) #index() Get the index of an element in the list

var = ['xs','dc','yyh','wzj'] result = var.index('dc') print(result) #reverse() List reverse operation

var = ['a','b','c','d'] print(var) var.reverse() print(var) #sort() Sort function

var = [23,342 ,34,32,75,59] #Default sorting ascending #var.sort() #print(var) #Descending


#var.sort(reverse=True) #print(var) #Custom


sorting rules #odd and even

def myfunc (num): result = num % 5

    return result var.sort(key=myfunc,reverse = True) print(var) a = [4,5,66,45, 99] # 0 1 0 1 1

# 1 0 1 0 0 #a.sort(key=ceshi,reverse=False)

a.sort(key = lambda x:x%2==0) #print(a)


def ceshi(x): return x%2 == 0 a.sort(key=ceshi) print(a) #sort Sort according to the return value Features Sort based on the original list

''' > < >= < ;= != == true 1 false 0 True + 1 1+1 1 + 1.1 2.1 bool int float float() int() bool() ''' #tuple

 

 

 

  (tuple is also a combination of a set of ordered data, The only difference from lists is that tuples cannot be modified) #Create a tuple of a single element#var = (13,)

var = 23, print(var,type(var)) #Tuples can only be accessed

var = ( 'yy','bb','dlrb','glnz') print(var[1]) print(var[-2]) #Sequence operation of tuples# +

var1 = (1,3,5,7, 9) var2 = (2,4,6,8,10) result = var1 + var2 print(result) #list or tuple with many layers

girls = ( ( ('Xiao Zhao','Xiao Qian'), ('Xiao Li','Xiao Zhou') ), ( ('Xiao Wu','Xiao Zheng'), ('Xiao Wang','Xiao Liu') ) ) #Access the content in the multi-layer tuple

print(girls[1 ]) print(girls[1][1]) print(girls[1][1][0]) #tuple comprehension->generator-> If not, don't give

var = (1,2,3,4,5,6,7,8,9) result = (i * 2 for i in var) print(result)#The result is a generator

for a in result: print(a)