使用Python中的字符串切片来查找字符串的前半部分长度？

Question

I'm working on an assignment in PyCharm, and have been tasked with the following problem:

The len() function is used to count how many characters a string contains. Get the first half of the string storied in the variable 'phrase'.

Note: Remember about type conversion.

Here's my code so far that it's given me:

phrase = """
It is a really long string
triple-quoted strings are used
to define multi-line strings
"""

first_half = len(phrase)
print(first_half)

I have no idea what to do. I need to use string slicing to find the first half of the string "phrase". Any help appreciated. I apologize for my ignorance.

Answer 1

仅将字符串的前半部分切成薄片，请确保在字符串长度奇数的情况下使用// ，例如：

print phrase[:len(phrase) // 2] # notice the whitespace in your literal triple quote

Answer 2

Try something like:

first_half = len(phrase)
print(phrase[0:first_half/2])

It will need to be smarter to handle strings of odd length. See this question for more on slicing.

Answer 3

first_half = phrase[:len(phrase)//2] or phrase[:int(len(phrase)/2)]

Answer 4

Note: Remember about type conversion.

In Python 2 the division will yield an int, however in Python 3 you want to use an int division like this half = len(phrase) // 2

Below is a Python 2 version

>>> half = len(phrase) / 2
>>> phrase[:half]
'\nIt is a really long string\ntriple-quoted st'

No need for the 0 in phrase[0:half] , phrase[:half] looks better :)

Answer 5

Try this print(string[:int(len(string)/2)])

len(string)/2 returns a decimal normally so that's why I used int()

Answer 6

Use slicing and bit shifting (which will be faster should you have to do this many times):

>>> s = "This is a string with an arbitrary length"
>>> half = len(s) >> 1
>>> s[:half]
'This is a string wit'
>>> s[half:]
'h an arbitrary length'

Answer 7

Try this:

phrase = """
It is a really long string
triple-quoted strings are used
to define multi-line strings
"""
first_half = phrase[0: len(phrase) // 2]
print(first_half)

Answer 8

you can simply slicing a string using it's indexes. For Example:

def first_half(str):
  return str[:len(str)/2]

The above function first_half accept a string and return it's half using slicing