Home > Article > Backend Development > Python zero-based introduction three --- (for loop + list)
The structure of Python's for loop is still very different from that of C, C++ and other languages, but it is still easy to get started. Python's list is similar to the array in C language, but compared with the function of the array More powerful, the joke is on the array of hormones.
For loop
(1)For loop syntax structure:
For element in variable (list, etc.)
(2) For loop is used in conjunction with the Range() function
The syntax of the range() function is: range([start],stop[,step =1])
Generally, the For loop is used with the range() function.
The first parameter is the starting number, the second is the ending number (not including the ending number), and finally One parameter is the step size, which defaults to 1, and the starting position defaults to 0.
2. List: A person who has taken steroids Array
(1) Definition of list and output of elements
Flag of list: [ , , ,]
Definition of list: List name = [Element 1, Element 2, Element 3...]
(2) List related operations
a. Add elements to the list
1. Use append() The function adds elements to the list
2. Use the extend() function to add elements to the list
3. Use the insert() function to add elements to the list
#b. Delete elements from the list
1. Use the remove() function to delete elements. The parameters are The deleted element, not the index
Use the pop() function to delete the element in the list. The last element is deleted by default. You can also fill in a parameter to delete the specified element. Position element.
Use the del statement to delete elements, del list name [specify the index of the element]
The above is about lists The operation of some simple elements will be added in time if there is more in the future.
Attached is the source code of the operation:
#For循环的联系 print("======For循环练习======") str1="For循环练习"for i in str1: print(i,end=" ") print("\n") print("======range()与For循环的搭配使用======") #一般情况下将For循环与range()函数搭配使用 #range()函数的语法是:range([start],stop[,step=1]) #第一个参数是起始数字,第二个是结束的数字(并不包括结束的数字) #最后一个参数是步长,默认为1,起始位置默认为0for m in range(5): print(m,end="") print("\n")for n in range(1,10,2): print(n,end="")print("\n") #列表的练习:一个打了激素的数组 #一个列表的标志:[,,,] print("------输出整个列表------")list=["小甲鱼","小布丁","迷途"] print(list)print("------输出列表中的元素------")list=["小甲鱼","小布丁","迷途"]for i in range(3): #一定要注意列表中的元素从0开始 print(list[i],end=" ") print("\n") print("------创建一个混合类型元素的列表------") mixture=["耀相惜",1,2]for i in range(3): print(mixture[i],end=" ") print("\n") #向列表中添加元素,在元素的末尾添加元素 list.append("耀相惜")print(list,"\n") #获取列表的长度print("列表中的元素的个数为:%d"%len(list),"\n") #向列表末尾一次添加多个元素,使用extend,参数为一个列表 listadd=["Guoxiangyao","Xiaoshuai"]list.extend(listadd)for i in range(6): print(list[i],end=" ") print("\n") #使用insert(,)函数插入数据#其中第一个元素为要插入的元素的位置#第二个参数为要插入的元素 list.insert(0,"小小甲鱼") for i in range(7): print(list[i],end=" ") print("\n")#从列表中获得、删除某个元素 list.remove("小甲鱼") #删除元素是指定元素,而不是索引 for i in range(5): print(list[i],end=" ") print("\n")#使用索引删除元素del list[0]for i in range(4): print(list[i],end=" ")print("\n") #删除列表的最后一个元素,使用pop()函数 list.pop()for i in range(3): print(list[i],end=" ") print("\n") #也可以使用在pop()中加入元素的索引,弹出指定位置的元素 list.pop(0)for i in range(2): print(list[i],end=" ")
The above is the content of the third zero-based introduction to Python --- (for loop + list). For more related content, please pay attention to the PHP Chinese website (www.php .cn)!