python的if语句

a=[2,3,4]if a[0]>3:    print("this is run")elif a[2]==4:    print "this is four"else:    print "no run"b=(1,2,3,4)if b[0]>2:    print "this is one step"else:    print "this is two step"# output# this is four# this is two step

语法中语句的尾部都加了冒号。这是感觉和C中不同之处。而且条件表达式不用括号。