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Python Tuple Methods

count()

count() 方法返回指定元素(element)在元组中出现的次数

tuple.count(element)

single argument: element - 要被计算的元素(element)

count() 方法返回元素 (element) 在元组中出现的次数

Use of Tuple count()

# 
# vowels tuple
vowels = ('a', 'e', 'i', 'o', 'i', 'u')

# count element 'i'
count = vowels.count('i')

# print count
print('The count of i is:', count)

# count element 'p'
count = vowels.count('p')

# print count
print('The count of p is:', count)

Result 1

The count of i is: 2
The count of p is: 0

Count List and Tuple Elements Inside Tuple

# random tuple
random = ('a', ('a', 'b'), ('a', 'b'), [3, 4])

# count element ('a', 'b')
count = random.count(('a', 'b'))

# print count
print("The count of ('a', 'b') is:", count)

# count element [3, 4]
count = random.count([3, 4])

# print count
print("The count of [3, 4] is:", count)

Result 2

The count of ('a', 'b') is: 2
The count of [3, 4] is: 1

index()

index() 方法返回 tuple 中指定元素 (element) 的索引值 (index)

tuple.index(element, start, end)

index() 方法最多接收三个输入参数：

  • element：被 search 的元素
  • start (optional)：从该 index 处开始查询
  • end (optional)：在该 index 处结束查询
  • index() 方法返回在 tuple 中指定元素 (element) 的索引值
  • 如果指定的元素找不到，会抛出一个 ValueError 异常

index() 方法，只会返回被查询元素所匹配到的第一个索引值

Find the index of the element

# vowels tuple
vowels = ('a', 'e', 'i', 'o', 'i', 'u')

# index of 'e' in vowels
index = vowels.index('e')
print('The index of e:', index)

# element 'i' is searched
# index of the first 'i' is returned
index = vowels.index('i')

print('The index of i:', index)

Result 1

The index of e: 1
The index of e: 2

Index of the Element not Present in the Tuple

# vowels tuple
vowels = ('a', 'e', 'i', 'o', 'u')

# index of'p' is vowels
index = vowels.index('p')
print('The index of p:', index)

Result 2

ValueError: tuple.index(x): x not in tuple

Working of index() With Start and End Parameters

# alphabets tuple
alphabets = ('a', 'e', 'i', 'o', 'g', 'l', 'i', 'u')

# index of 'i' in alphabets
index = alphabets.index('e')   # 2
print('The index of e:', index)

# 'i' after the 4th index is searched
index = alphabets.index('i', 4)   # 6
print('The index of i:', index)

# 'i' between 3rd and 5th index is searched
index = alphabets.index('i', 3, 5)   # Error!
print('The index of i:', index)

Result 3

The index of e: 1
The index of i: 6
Traceback (most recent call last):
File "<string>", line 13, in <module>
ValueError: tuple.index(x): x not in tuple

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