1.遍历列表中的元素:用for(操作元素)和while(操作索引)实现
#将列表中的所有元素打印出来
#for循环主要结合成员运算符使用,此时只能操作元素
list1= ["and",567,"abc"]
for element in list1:
print(element)
else:
print("over")
#用while实现,操作的是列表索引
num = 0
while num < len(list1):
print(list1[num])
num += 1
2.列表生成器的使用
#列表生成器:生成具有一定规律的列表,此时可操作列表索引
indexList = range(0,len(list1)) #range([start,]end[,step]),其中start和step可不写,默认为0和1
for i in indexList:
print(i)
print(list1[i])
3.练习for循环和列表生成器的结合使用 ,枚举的使用
#练习:
#1.计算1~100之间所有整数的和
sum = 0
indexList1 = range(1,101)
for i in indexList1:
sum += i
print(sum)
#2.计算1~100之间所有偶数的和
sum = 0
indexList2 = range(0,101,2)
for i in indexList2:
sum += i
print(sum)
#枚举:同时遍历索引和元素
for i,element in enumerate(list1):
print(i,element)
4.二维列表的遍历:用for循环的方法
#二维列表的遍历
list2 = [[23,54,64,6],[54,4,65],[54,65,657]]
subList = list2[1]
print(subList[1])
print(list2[1][1])
#嵌套for循环
for subelement in list2:
for element in subelement:
print(element)
5.练习:乘法表、特定整数之和、列表元素的遍历和删除
#练习:
#1.写乘法表
for x in range(1,10):
for y in range(1,x + 1):
print("%d*%d=%d"%(y,x,x*y),end=" ")
print("")
#2.计算从1到100以内所有能被3或者17整除的和并输出%
sum = 0
for i in range(1,101,1):
if i % 3 == 0 or i % 17 == 0:
sum += i
print(sum)
#3.计算从1到100以内能被7或者3整除但不能同时被这两者整除的数的个数
sum = 0
for i in range(1,101,1):
if (i % 3 == 0 or i % 7 == 0) and i % 21 != 0 :
sum += i
print(sum)
#需求一:逐一显示列表中索引为奇数的元素;需求二:将属于一个列表且不属于另外一个列表的元素,重新定义一个新的列表
#需求三:已知列表namelist=['stu1','stu2','stu3','stu4','stu5','stu6','stu7'],删除列表
#removelist=['stu3','stu7','stu9'];将属于removelist列表中的每个元素从namelist中移除
List1 = ["sun","mon","tue","wed","thu","fri","sat"]
for i in range(len(List1)):
if i % 2 != 0:
print(List1[i])
List2 = ["sun","mon","tue","fri","sat"]
List3 = []
for i in List1:
if i not in List2:
List3.append(i)
print(List3)
namelist = ['stu1','stu2','stu3','stu4','stu5','stu6','stu7']
removelist = ['stu3','stu7']
for i in range(len(removelist)):
namelist.remove(removelist[i])
print(namelist)