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Python成员和标识操作符详细指南

成员运算符

成员标识运算符是用于验证值的成员标识的运算符。它测试序列中的成员标识, 例如字符串, 列表或元组。

在in运算符中:” in”运算符用于检查一个值是否存在于序列中。如果找到指定序列中的变量, 则评估为true, 否则为false。

# Python program to illustrate
# Finding common member in list 
# using 'in' operator
list1 = [ 1 , 2 , 3 , 4 , 5 ]
list2 = [ 6 , 7 , 8 , 9 ]
for item in list1:
     if item in list2:
         print ( "overlapping" )      
else :
     print ( "not overlapping" )

输出如下:

not overlapping

没有使用in运算符的相同示例:

# Python program to illustrate 
# Finding common member in list 
# without  using 'in' operator
  
#  Define a function() that takes two lists
def overlapping(list1, list2): 
  
     c = 0
     d = 0
     for i in list1:
         c + = 1
     for i in list2:
         d + = 1
     for i in range ( 0 , c):
         for j in range ( 0 , d):
             if (list1[i] = = list2[j]):
                 return 1
      return 0
list1 = [ 1 , 2 , 3 , 4 , 5 ]
list2 = [ 6 , 7 , 8 , 9 ]
if (overlapping(list1, list2)):
     print ( "overlapping" )
else :
     print ( "not overlapping" )

输出如下:

not overlapping

“not in”运算符-

如果找不到指定序列中的变量, 则求值为true, 否则为false。

# Python program to illustrate
# not 'in' operator
x = 24
y = 20
list = [ 10 , 20 , 30 , 40 , 50 ];
  
if ( x not in list ):
    print ( "x is NOT present in given list" )
else :
    print ( "x is  present in given list" )
  
if ( y in list ):
    print ( "y is present in given list" )
else :
    print ( "y is NOT present in given list" )

标识运算符

在Python中, 用于确定值是特定类还是类型。它们通常用于确定某个变量包含的数据类型。

有不同的标识运算符, 例如

“is”运算符–

如果运算符两侧的变量指向同一对象, 则计算为true, 否则为false。

# Python program to illustrate the use 
# of 'is' identity operator
x = 5
if ( type (x) is int ):
     print ( "true" )
else :
     print ( "false" )

输出如下:

true

“is not”运算符–

如果运算符两侧的变量指向同一个对象, 则结果为false, 否则为true。

# Python program to illustrate the 
# use of 'is not' identity operator
x = 5.2
if ( type (x) is not int ):
     print ( "true" )
else :
     print ( "false" )

输出如下:

true

首先, 你的面试准备可通过以下方式增强你的数据结构概念:Python DS课程。


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