python的代码块分隔符: 1. x=1 2. if x: 3. 2 4. if y: 5. print'block2' 6. print'block1' 7. print 'block0' 1. 2. 3. 4. 5. 6. 7. 以上面这段代码为例,包含三个模块:第一个完全没有缩进,第二个缩进四格,第三个缩进八格,这里注意,python不在乎你怎么缩进代码。只在乎缩进是否一致!
@echo off set "file=example.txt" if exist "%file%" ( echo 文件存在 ) else ( echo 文件不存在 ) 在这个示例中,我们使用了exist关键字来检查文件是否存在。如果文件存在,我们输出“文件存在”,否则输出“文件不存在”。 需要注意的是,if/then/else语句必须在批处理脚本中使用,而不能在命令行中直接使用...
If the condition is not true, then the statement in the body of the else statement is executed. The body of if and else statements starts with indentation. Let’s see an example of the implementation of the if…else statement. Python 1 2 3 4 5 6 7 i = 20; if (i < 15): ...
实例(Python 3.0+) # Filename :test.py# author by : www.runoob.com# 内嵌 if 语句num=float(input("输入一个数字:"))ifnum>=0:ifnum==0:print("零")else:print("正数")else:print("负数") 执行以上代码输出结果为: 输入一个数字:0零 '输入的数字是零')elif0:print'输入的数字是正数')else:...
Python will evalute the if condition and if it evaluates to False then it will evalute the elif blocks and execute the elif block whose expression evaluates to True. If multiple elif conditions become True, then the first elif block will be executed. The following example demonstrates if, ...
Python If Else Statement - Learn how to use if and else statements in Python with practical examples. Master conditional logic in your Python programming.
Python String Empty Check ExpressionTable 1. Quick Examples of Checking if String is Empty If you are in a hurry, below are some quick examples of how to check whether the given string is empty or not in Python. # Quick Examples
3rd line – 6th line: All these lines have equal indentation at the beginning of the statement. In this example, all these 4 print statements have 2 spaces at the beginning. So, these statements will get executed then the if condition becomes true. ...
我试着把if语句改成else语句。但如果有效,仍然只有一半。这意味着,用户输入一个单词,如果该单词=Next,则会删除该行中的第一个人。如果用户键入除“下一步”以外的任何其他单词,则会将其添加到列表的末尾。 Example below: # This is just a line manager :D ...
If test_expression1 evaluates to False, then test_expression2 is evaluated. If test_expression2 is True, code block 2 is executed. If test_expression2 is False, code block 3 is executed. Example: R if...else if...else Statement x <- 0 # check if x is positive or negative or ze...