%s"%a[-1])###取最后一个元素print("a[:-1]->%s"%a[:-1])###除了最后" />
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序列冒号的使用:-1
a = [0, 1, 2, 3, 4, 5] print("[0, 1, 2, 3, 4, 5] 测试结果为:") print("a[-1]-> %s" %a[-1]) ###取最后一个元素 print("a[:-1]-> %s" %a[:-1]) ### 除了最后一个取全部 print("a[::-1]-> %s" %a[::-1]) ### 取从后向前(相反)的元素 print("a[2::-1]-> %s" %a[2::-1]) ### 取从下标为2的元素翻转读取 print("a[3::-1]-> %s" %a[3::-1]) ### 取从下标为3的元素翻转读取 输出结果================================ [0, 1, 2, 3, 4, 5] 测试结果为: a[-1]-> 5 a[:-1]-> [0, 1, 2, 3, 4] a[::-1]-> [5, 4, 3, 2, 1, 0] a[2::-1]-> [2, 1, 0] a[3::-1]-> [3, 2, 1, 0] 字符串拼接数字输出,占位符号re = math.floor(32.9) print("floor(32.9) is ") print("floor(32.9) is %s" %re) print("floor(32.9) is %d" %re) 输出结果===================================== floor(32.9) is floor(32.9) is 32 floor(32.9) is 32 单双引号及转义字符print("hello") print('"hello",he said') print("\"Hello, world!\" she said") print("hello "+ "world") #"""这种情况无需转义字符""" print(""""hello!",he said to her,and 'nice to meet you!',she replyed!""") #原始字符串,转移字符串在这里面失效 print(r'C:\Program Files\python') 输出结果========================================== hello "hello",he said "Hello, world!" she said hello world "hello!",he said to her,and 'nice to meet you!',she replyed! C:\Program Files\python 列表 序列greeting = 'hello' print("0位置是字母\"%s\" -1位置是字母\"%s\"" %(greeting[0], greeting[-1])) #切片---------------------------------------------------------------------------- numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] print("#numbers[0:1] is ") print(numbers[0:1]) print("#numbers[0:2] is ") print(numbers[0:2]) print("#numbers[-3:-1] is ") print(numbers[-3:-1]) 输出结果============================================= 0位置是字母"h" -1位置是字母"o" #numbers[0:1] is [1] #numbers[0:2] is [1, 2] #numbers[-3:-1] is [8, 9] #序列相加--------------------------------------------------------------- print("#[1, 2, 3] + [4, 5, 6] is ") print( [1, 2, 3] + [4, 5, 6]) #in 运算符 permissions = 'we are' print("""#'w' in permissions""") print('w' in permissions) print('we' in permissions) 输出结果====================================== #[1, 2, 3] + [4, 5, 6] is [1, 2, 3, 4, 5, 6] #'w' in permissions True True #切片插入---------------------------------------------------------------- numbers = [1,5] numbers[1:1] = [2,3,4] print("""#numbers 插入后是""") print(numbers) 输出结果============================== #numbers 插入后是 [1, 2, 3, 4, 5] 字符串#参数-------------------------------------------------------------------------- format = "Hello, %s ,%s end" values = ("ni",'hao') print(format % values) #模板 tmpl= Template("Hello, $chineseyou ,$chinesegood end") print(tmpl.substitute(chineseyou = "ni",chinesegood = "hao")) 输出结果=========================================== Hello, ni ,hao end Hello, ni ,hao end #简单替换方式----------------------------------------------------------------------- print( "{3} {0} {2} {1} {3} {0}".format("be", "not", "or", "to")) print( "{name} is approximately {value:.2f}.".format(value=math.pi, name="π")) 输出结果============================================== to be or not to be π is approximately 3.14. #字段替换顺序和名称 3 2 4 1---------------------------------------------------------- print( "{foo} {1} {bar} {0}".format(1, 2, bar=4, foo=3)) 输出结果=============================================== 3 2 4 1 #字符串替换,使用中的fullname---------------------------------------------------------- fullname = ["nash", "sundy"] print("Mr {name[0]}".format(name=fullname)) print('One googol is {:,}'.format(10**100)) print( "Pi is {pi:.4f}".format(pi=math.pi)) 输出结果=================================================== Mr nash One googol is 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Pi is 3.1416 #符号填充----------------------------------------------------------------------------------------- #所有字符一共12位 000000003.14 print( '{:012.2f}'.format(math.pi)) #多余空位的对齐方式:左\居中\右 print('{0:10.2f}'.format(math.pi)) 输出结果=================================================== 000000003.14 3.14 3.14 3.14 |
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