Python:在没有列表的情况下取第一个字符

Question

我的代码是关于使用每个单词/数字的第一个字符/数字作为句子/短语中的字符来创建密码，并按原样打印它。

Example: Stop and smell the 350 "roses". -> Sast3r. (Ignoring quotations using r instead)

使用列表会非常容易，但您不能在我的代码的作业中使用它们。所以，在我做了这么多事情之后，我现在不知道该怎么办

功能:

def create_password(phrase):
q = "'"  # quotations
dq = '"'  # double quotes

password = phrase[0]

for i in phrase:
    x = phrase.find(" ")
    if i.isalnum:
        password += phrase[x + 1]
    elif x == q or x == dq:
        password += phrase[x + 2]

return password

主要:

# Imports
from credentials import create_password

# Inputs
phrase = str(input("Enter a sentence or phrase: "))

# Outputs
password = create_password(phrase)
print(password)

Answer 1

我认为遍历整个短语更直接，而不必担心空格分割。相反，请跟踪您是否刚刚看到过一个空间。您只想在看到空格后添加字符。

def create_password(phrase):
    q = "'"  # quotations
    dq = '"'  # double quotes

    #Initialize the password to be an empty string
    password = ""

    #We are at the start of a new word (want to add first index to password)
    new_word = True

    #Walk through every character in the phrase
    for char in phrase:

        #We only want to add char to password if the following is all true:
        #(1) It's a letter or number
        #(2) It's at the start of a new word
        #(3) It's not a single quote
        #(4) It's not a double quote
        if char.isalnum and new_word:
            if char != q and char != dq:
                password += char
                new_word = False #<-- After adding char, we are not at a new word

        #If we see a space then we are going to be at a new word
        elif char == " ":
            new_word = True

    return password

p = create_password('Stop and smell the 350 "roses"')
print(p)

输出:

Sast3r