程序案例 内联代码片。
// 打印信息 message = "Hello World!" print(message) Message = "Hello Python Crash Course World!" print(message) // 输出结果 Hello World! Hello Python Crash Course World! Python始终记录变量的最新值删除字符串末尾空白rstrip(),删除字符串开头空白lstrip(),同时剔除字符串两端的空白strip()。删除只是暂时的,要永久删除需要将值赋给字符串变量。
// 打印信息 >>>language = ' python ' >>>language.rstrip() ' python' >>>language.lstrip() 'python ' >>>language.strip() 'python'str()转换成字符串
// 打印信息 age = 23 message = "Happy" + str(age) + "rd Birthday!" print(message) // 输出结果 Happy 23rd Birthday!列表内可以放入任何元素,不可对列表元素直接赋值,但可以改变列表变量的值。
方法为append()
// 打印信息 bicycles = ['trek','cannondale','redline','specialized'] print(bicycles) bicycles.append('end') print(bicycles) // 输出结果 ['trek','cannondale','redline','specialized'] ['trek','cannondale','redline','specialized','end']方法为insert()
// 打印信息 bicycles = ['trek','cannondale','redline','specialized'] print(bicycles) bicycles.insert(1,'insert') print(bicycles) // 输出结果 ['trek','cannondale','redline','specialized'] ['trek','insert','cannondale','redline','specialized']pop方法默认删除最后一位元素,如需指定删除元素位置,可向该方法内传递参数。
// 打印信息 bicycles = ['trek','cannondale','redline','specialized'] print(bicycles) poped_bicycle = bicycles.pop() print(bicycles) print(poped_bicycle) poped_bicycle1 = bicycles.pop(1) print(bicycles) print(poped_bicycle1) // 输出结果 ['trek','cannondale','redline','specialized'] ['trek','cannondale','redline'] specialized ['trek','redline'] cannondale方法remove()只删除第一个指定的值。如果要删除的值可能在列表中出现多次,就需要使用循环判断是否删除了所有这样的值。
下列操作对列表的内容是永久性的
// 打印信息 bicycles = ['trek','cannondale','redline','specialized'] print(bicycles) bicycles.sort() print(bicycles) bicycles.sort(reverse=True) print(bicycles) // 输出结果 ['trek','cannondale','redline','specialized'] ['specialized','redline','cannondale','trek'] ['trek','cannondale','redline','specialized']