>>>symbols ='HPQ,AAPL,IBM,MSFT,YHOO,DOA,GOOG' 使用字符串的split()方法把 symbols 拆分为一个包含股票代码名字的列表: >>>symlist = symbols.split(',') 练习1.19:提取和重新分配列表元素 尝试一些查找: >>>symlist[0]'HPQ'>>>symlist[1]'AAPL'>>>symlist[-1]'GOOG'>>>symlist[-2]'DOA'>>...
您可以通过提供更多参数来选择您选择的 Python 解释器,例如以下命令: $ virtualenv -p /usr/bin/python2.7name-of-virtual-environment 这将创建一个使用 Python 2.7 的虚拟环境。在开始使用此虚拟环境之前,我们必须激活它: $ source name-of-virtual-environment/bin/activate 现在,在命令提示符的左侧,将显示活动虚...
We have a list of names. Each name consists of a first name and last name. In addition, there are several users with the same last name. In such a case, we want them to be sorted by their first names. names.sort() names.sort(key=lambda e: e.split()[-1]) First, we sort the...
The first expression returns True because 5 is in the list of numbers. The second expression returns False because 8 isn’t in the list. The not in membership operator runs the opposite test as the in operator. It allows you to check whether an integer value is not in a collection of ...
While tuples could just be thought of as immutable lists, we usually use the two quite differently: tuples are for storing a fixed number of values, often of different types. For more on the nature of tuples see How to make a tuple and Mutable tuples. List Comprehension (also set & ...
通过symbols方法将字符串声明为符号变量,。 代码语言:python 代码运行次数:0 运行 AI代码解释 importsympy# 声明单个变量x=sympy.symbols('x')print(x)# 声明多个变量,以下三个方法都可以x,y=sympy.symbols(['x','y'])x,y=sympy.symbols("x,y")x,y=sympy.symbols("x y") ...
Pyplot is a collection of functions that make matplotlib work like Matlab,which you may be familiar with. Pyplot是一组函数,使matplotlib像Matlab一样工作,您可能熟悉这些函数。 Pyplot is especially useful for interactive work,for example, when you’d like to explore a dataset or visually examine you...
;; This code adds up to 10000 from 0 via calling a function that takes a variable number of arguments.;; That function then reduces over the argument list to add up all given arguments.(defn add-fn [& args] (reduce-add0args)) (loop[x 0] (if(eqx10000) x (recur (add-fn x1))...
a list of available modules, keywords, symbols, or topics, type"modules", "keywords", "symbols...
>>> for s in symlist: print('s =', s) # Look at the output 练习1.21:成员测试 使用in 或者not in 操作符来检查 'AIG','AA',和 'CAT' 是否在 symbols 列表中: >>> # Is 'AIG' IN the `symlist`? True >>> # Is 'AA' IN the `symlist`? False >>> # Is 'CAT' NOT IN the...