if boolean_expression: statement(s) 注意布尔表达式后边的冒号是必须的。 2.1. 基本的 if 示例 # Basic Python If Example a =2 b=5 if a <b: print(a,'is less than',b) 执行及输出: 2.2. 多条件表达式 单个表达式里有多条件的话需要使用逻辑操作符将其分开。 # Example
Python 中用 elif 代替了else if,所以if语句的关键字为:if – elif – else。 if condition_1: statement_block_1 elif condition_2: statement_block_2 else: statement_block_3 1. 2. 3. 4. 5. 6. 流程图如下所示: 如果"condition_1" 为 True 将执行 "statement_block_1" 块语句,如果 "conditio...
Not Equals:a != b Less than:a < b Less than or equal to:a <= b Greater than:a > b Greater than or equal to:a >= b These conditions can be used in several ways, most commonly in "if statements" and loops. An "if statement" is written by using theifkeyword. ...
如果“condition_1” 为 True 将执行 “statement_block_1” 块语句,如果 “condition_1” 为False,将判断 “condition_2”,如果"condition_2" 为 True 将执行 “statement_block_2” 块语句,如果 “condition_2” 为False,将执行"statement_block_3"块语句。 Python中用elif代替了else if,所以if语句的关键...
range(2, n): ... if n % x == 0: ... print(n, 'equals', x, '*', n//x)...
4.1 if Statements Perhaps the most well-known statement type is the if statement. For example: >>> x = int(input("Please enter an integer:")) Please enter an integer: 42 >>> if x < 0: x = 0 print('Negative changed to zero') ...
...2isa prime number3isa prime number4equals2*25isa prime number6equals2*37isa prime number8equals2*49equals3*3 (Yes, this is the correct code. Look closely: theelseclause belongs to theforloop,nottheifstatement.) (是的,这是正确的代码,仔细看,else子句是属于里面的for循环的,而不是属于...
1.有时候两个字符串打印出来看着⼀样，但是判断却是False？如果两个字符串末尾有其他符号，⽐如回车‘\n'，print的时候⽆法发现的，所以需要strip：a=a.strip()b=b.strip()if a==b:print "True"2.有时候==判断是 True ，is 判断却是 False?这是因为两个字符串来⾃不同的内存块，内存地址不⼀...
Note python has this really weird error if you define local variable in a function same name as the global variable, program will promptUnboundLocalError. child class object overrides parent class methods input: classfruit:defprint(self):print('a')defeat(self):print('b')classapple(fruit):defpr...
2 is a prime number 3 is a prime number 4 equals 2 * 2 5 is a prime number 6 equals 2 * 3 7 is a prime number 8 equals 2 * 4 9 equals 3 * 3 Note In the preceding example, theelsestatement belongs to theforloop, not to theifstatement. ...