blocks|key|905987|text|它被称为index。例如|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|905988|>>>+import+string
>>>+string.lowercase.index('b')
1
>>>+|code-block|syntax|javascript|905989|注意:在Python3中，string.lowercase已重命名为string.ascii_lowercase。|905990|entityMap^0|4|5|0|0|D|G|Y|M|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

It is called <code>index</code>. For e.g.

<pre><code>&gt;&gt;&gt; import string
&gt;&gt;&gt; string.lowercase.index('b')
1
&gt;&gt;&gt; 
</code></pre>

Note: in Python 3, <code>string.lowercase</code> has been renamed to <code>string.ascii_lowercase</code>.

blocks|key|906093|text|不使用导入|type|unstyled|depth|inlineStyleRanges|entityRanges|data|906094|def+char_position(letter):
++++return+ord(letter)+-+97

def+pos_to_char(pos):
++++return+chr(pos+%2B+97)|code-block|syntax|javascript|906095|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Without the import 

<pre><code>def char_position(letter):
 return ord(letter) - 97

def pos_to_char(pos):
 return chr(pos + 97)
</code></pre>

blocks|key|689827|text|可以使用ord()获取字符的ASCII位置，使用chr()将ASCII位置转换为字符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|689828|编辑:更新以换行字母表，以便a-1映射到z，z%2B1映射到a|689829|例如：|689830|my_string++=+"zebra"
difference+=+-1
new_string+=+''.join((chr(97%2B(ord(letter)-97%2Bdifference)+%25+26)+for+letter+in+my_string))|code-block|syntax|javascript|689831|这将创建一个字符串，所有字符在字母表中向后移动一个空格('ydaqz')。它只适用于小写的单词。|689832|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|R|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You can use ord() to get a character's ASCII position, and chr() to convert a ASCII position into a character.

EDIT: Updated to wrap alphabet so a-1 maps to z and z+1 maps to a

For example:

<pre><code>my_string = "zebra"
difference = -1
new_string = ''.join((chr(97+(ord(letter)-97+difference) % 26) for letter in my_string))
</code></pre>

This will create a string with all the characters moved one space backwards in the alphabet ('ydaqz'). It will only work for lowercase words.

blocks|key|689931|text|#+define+an+alphabet
alfa+=+"abcdefghijklmnopqrstuvwxyz"

#+define+reverse+lookup+dict
rdict+=+dict([+(x[1],x[0])+for+x+in+enumerate(alfa)+])

print+alfa[1]+#+should+print+b

print+rdict["b"]+#+should+print+1|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|689932|rdict是一个字典，它通过逐个字母表一次一个字符的方式创建。enumerate函数返回一个带有列表索引和字符的元组。我们通过使用以下代码创建一个新的元组来颠倒顺序：(+x[1],+x[0])，然后将元组列表转换为字典。由于字典是一个哈希表(键、值)数据结构，我们现在可以查找任何字母表字符的索引。|unstyled|offset|length|style|CODE|689933|然而，这并不是你想要解决的问题，如果这是一个类作业，如果你提交了抄袭，你可能会得到0分。为了对字符串进行编码，首先创建第二个字母表，该字母表被组织为alfa2n的编码形式。在您的示例中，第二个字母表只是移动了两个字符，但您也可以随机地对字符进行混洗或使用其他模式对它们进行排序。所有这些都将继续适用于其他字母表，如希腊语、西里尔语等。|689934|entityMap^0|0|2B|D|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|P|8|@$G|Q|H|R|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|F|7|T|8|@]|9|@]|A|$]]]|N|$]]

<pre><code># define an alphabet
alfa = "abcdefghijklmnopqrstuvwxyz"

# define reverse lookup dict
rdict = dict([ (x[1],x[0]) for x in enumerate(alfa) ])

print alfa[1] # should print b

print rdict["b"] # should print 1
</code></pre>

rdict is a dictionary that is created by stepping through the alphabet, one character at a time. The enumerate function returns a tuple with the list index, and the character. We reverse the order by creating a new tuple with this code: <code>( x[1], x[0])</code> and then turn the list of tuples into a dictionary. Since a dictionary is a hash table (key, value) data structure, we can now look up the index of any alphabet character.

However, that is not what you want to solve your problem, and if this is a class assignment you would probably get 0 for plagiarism if you submit it. For encoding the strings, first create a SECOND alphabet that is organised so that alfa2[n] is the encoded form of alfa[n]. In your example, the second alphabet would be just shifted by two characters but you could also randomly shuffle the characters or use some other pattern to order them. All of this would continue to work with other alphabets such as Greek, Cyrillic, etc.

blocks|key|690011|text|我刚刚开始学习Python，所以我不知道与其他方法相比，它的效率有多高，但它是有效的。此外，无论文本是大写还是小写，或者是否有任何标点符号等都无关紧要。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|690012|如果要更改所有字母：|690013|from+string+import+maketrans

textin+=+"abcdefghijklmnopqrstuvwxyz"
textout+=+"cdefghijklmnopqrstuvwxyzab"
texttrans+=+maketrans(textin,+textout)

text+=+"qcc,+gr+umpiq"

print+text.translate(texttrans)|code-block|syntax|javascript|690014|还可以更改一些字符：|690015|from+string+import+maketrans

textin+=+"81972"
textout+=+"Seios"
texttrans+=+maketrans(textin,+textout)

text+=+"811,+9t+w7rk2"

print+text.translate(texttrans)|690016|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I've only just started learning Python, so I have no idea how efficient this is compared to the other methods, but it works. Also, it doesn't matter whether the text is upper case, lower case or if there is any punctuation etc.

If you want to change all letters:

<pre><code>from string import maketrans

textin = "abcdefghijklmnopqrstuvwxyz"
textout = "cdefghijklmnopqrstuvwxyzab"
texttrans = maketrans(textin, textout)

text = "qcc, gr umpiq"

print text.translate(texttrans)
</code></pre>

Also works to change some characters:

<pre><code>from string import maketrans

textin = "81972"
textout = "Seios"
texttrans = maketrans(textin, textout)

text = "811, 9t w7rk2"

print text.translate(texttrans)
</code></pre>

blocks|key|906246|text|这里有一个可能对某些人有用的catch+all方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|906247|def+alphabet(arg,+return_lower=True):

++++"""
++++++++Indexing+the+english+alphabet+consisting+of+26+letters.+
++++++++Note:+zero+indexed

++++++++++++example+usage:

++++++++++++++++alphabet('a')
++++++++++++++++>>+0

++++++++++++++++alphabet(25,+return_lower=False)
++++++++++++++++>>+'Z'

++++++++:param+arg:+Either+type+int+or+type+chr+specifying+the+\
++++++++++++++++++++index+of+desired+letter+or+ther+letter+at+\
++++++++++++++++++++the+desired+index+respectivley.
++++++++:param+return_lower:+If+index+is+passes,+returns+letter+\
+++++++++++++++++++++++++with+corresponding+case.+Default+is+\
+++++++++++++++++++++++++set+to+True+(lower+case+returned).+
++++++++:returns:+integer+representing+index+of+passed+character+\
++++++++++++++++++++or+character+at+passed+index.
++++"""

++++arg+=+str(arg)
++++assert+arg.isdigit()+or+arg.isalpha()

++++if+arg.isdigit():
++++++++if+return_lower:
++++++++++++return+chr(int(arg)+%2B+97).lower()++
++++++++return+chr(int(arg)+%2B+97).upper()

++++return+ord(arg.lower())+-+97|code-block|syntax|javascript|906248|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here's a catch all method that might be useful for someone...

<pre><code>def alphabet(arg, return_lower=True):

 """
 Indexing the english alphabet consisting of 26 letters. 
 Note: zero indexed

 example usage:

 alphabet('a')
 &gt;&gt; 0

 alphabet(25, return_lower=False)
 &gt;&gt; 'Z'

 :param arg: Either type int or type chr specifying the \
 index of desired letter or ther letter at \
 the desired index respectivley.
 :param return_lower: If index is passes, returns letter \
 with corresponding case. Default is \
 set to True (lower case returned). 
 :returns: integer representing index of passed character \
 or character at passed index.
 """

 arg = str(arg)
 assert arg.isdigit() or arg.isalpha()

 if arg.isdigit():
 if return_lower:
 return chr(int(arg) + 97).lower() 
 return chr(int(arg) + 97).upper()

 return ord(arg.lower()) - 97
</code></pre>

I'm 90% sure there is a built in function that does this.

I need to find the position of a character in an alphabet. So the character "b" is position 1 (counting from 0), etc. Does anyone know what the function is called?

Thanks in advance!

EDIT: What i'm trying to do is to send all the characters X amount of "steps" back in the alpha bet, so if i have a string with "hi" it would be "gh" if i sent it back one step. There might be a better way of doing it, any tips?

Get character position in alphabet

数据结构

Python

我有90%的把握有一个内置的函数可以做到这一点。我需要找到一个字符在字母表中的位置。因此，字符"b“是位置1(从0开始计数)，等等。有人知道这个函数调用的是什么吗？提前感谢！编辑:我想要做的是把所有的字符X个“步骤”发回alpha赌注，所以如果我有一个带有"hi“的字符串，如果我把它发回一个步骤，它就是"gh”。也许有更好的方法，有什么建议吗？

问获取字母表中的字符位置
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