for陳述句中的if陳述句僅輸出else部分的print陳述句，即使if和elif部分滿足條件

我試圖讓 if/else 陳述句在 for 回圈中運行。盡管引數滿足其上面所有陳述句的標準，但輸出是 else 部分。這是我的代碼：

import string

print(string.ascii_lowercase)
print(string.ascii_uppercase)
print(string.ascii_letters)
print(string.digits)
print(string.punctuation)

my_string = '4n%$P9'
  
for index in range(0, len(my_string), 1):
  if my_string in string.ascii_lowercase:
    print("'{}' is a lowercase letter.".format(my_string))
  elif my_string in string.ascii_uppercase:
    print("'{}' is an uppercase letter.".format(my_string))
  elif my_string in string.digits: 
    print("'{}' is a digit in arabic.".format(my_string))
  elif my_string in string.punctuation:
    print("'{}' is a punctuation mark.".format(my_string))
  else:
    print("Does not compute.")

輸出是這樣的：

abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
0123456789
!"#$%&'()* ,-./:;<=>?@[\]^_`{|}~
Does not compute.
Does not compute.
Does not compute.
Does not compute.
Does not compute.
Does not compute.

我沒有收到語法錯誤，所以我想知道，我沒有使用正確的關鍵字嗎？邏輯有問題嗎？

uj5u.com熱心網友回復：

問題不在于if陳述句，而在于您的for回圈。看起來你想遍歷每個字符my_string并單獨測驗它，而不是my_string一次測驗：

for c in my_string:
    if c in string.ascii_lowercase:
        print(f"'{c}' is a lowercase letter.")
    elif c in string.ascii_uppercase:
        print(f"'{c}' is an uppercase letter.")
    elif c in string.digits: 
        print(f"'{c}' is a digit in arabic.")
    elif c in string.punctuation:
        print(f"'{c}' is a punctuation mark.")
    else:
        print(f"'{c}' does not compute.")

印刷：

'4' is a digit in arabic.
'n' is a lowercase letter.
'%' is a punctuation mark.
'$' is a punctuation mark.
'P' is an uppercase letter.
'9' is a digit in arabic.

請注意，c作為“不計算”訊息的一部分進行列印可以讓您查看未計算的字符 - 如果您my_string在原始代碼中這樣做了，您會看到：

'4n%$P9' does not compute.
'4n%$P9' does not compute.
'4n%$P9' does not compute.
'4n%$P9' does not compute.
'4n%$P9' does not compute.
'4n%$P9' does not compute.

對于問題所在，這將是一個很好的線索！

uj5u.com熱心網友回復：

您正在檢查整個字串是否是string模塊中每個常量的子字串。您想對字串中的每個字符執行該檢查，如下所示：

import string

my_string = '4n%$P9'
  
for char in my_string:
  if char in string.ascii_lowercase:
    print("'{}' is a lowercase letter.".format(char))
  elif char in string.ascii_uppercase:
    print("'{}' is an uppercase letter.".format(char))
  elif char in string.digits: 
    print("'{}' is a digit in arabic.".format(char))
  elif char in string.punctuation:
    print("'{}' is a punctuation mark.".format(char))
  else:
    print("Does not compute.")

這輸出：

'4' is a digit in arabic.
'n' is a lowercase letter.
'%' is a punctuation mark.
'$' is a punctuation mark.
'P' is an uppercase letter.
'9' is a digit in arabic.

uj5u.com熱心網友回復：

您正在嘗試比較整個字串是否在 中string.ascii_lowercase，而不僅僅是字母，您需要實際運行my_string[index].

import string

print(string.ascii_lowercase)
print(string.ascii_uppercase)
print(string.ascii_letters)
print(string.digits)
print(string.punctuation)

my_string = '4n%$P9'
  
for index in range(0, len(my_string), 1):
  if my_string[index] in string.ascii_lowercase:
    print("'{}' is a lowercase letter.".format(my_string[index]))
  elif my_string[index] in string.ascii_uppercase:
    print("'{}' is an uppercase letter.".format(my_string[index]))
  elif my_string[index] in string.digits: 
    print("'{}' is a digit in arabic.".format(my_string[index]))
  elif my_string[index] in string.punctuation:
    print("'{}' is a punctuation mark.".format(my_string[index]))
  else:
    print("Does not compute.")

標籤：Python for循环 if 语句

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