Develop Reference

How to search through each letter in a dictionary and use it properly

If I were to take a dictionary, such as
living_beings= {"Reptile":"Snake","mammal":"whale", "Other":"bird"}
and wished to search for individual characters (such as "a") (e.g.
for i in living_beings:
if "a" in living_beings:
print("a is here")
would there be an efficient- runs fastest- method of doing this?
The input is simply searching as outlined above (although my approach didn't work).
My (failed) code goes as follows:
animals=[]
for row in reader: #'reader' is simply what was in the dictionary
animals.append(row) #I tried to turn it into a list to sort it that way
for i in range(1, len(animals)):
r= animals[i]
for i in r:
if i== "a": #My attempt to find "a". This is obviously False as i= one of the strings in
k=i.replace("'","/") #this is my attempt at the further bit, for a bit of context
test= animals.append(k)
print(test)
In case you were wondering,
The next step would be to insert a character- "/"- before that letter (in this case "a"), although this is a slightly different problem and so not linked with my question and is simply there to give a greater understanding of the problem.
EDIT
I have found another error relating to dictionary. If the dictionary features an apostrophe (') the output is affected as it prints that particular word in quotes ("") rather that the normal apostrophes. EXAMPLE: living_beings= {"Reptile":"Snake's","mammal":"whale", "Other":"bird"} and if you use the following code (which I need to):
new= []
for i in living_beings:
r=living_beings[i]
new.append(r)
then the output is "snake's", 'whale', 'bird' (Note the difference between the first and other outputs). So My question is: How to stop the apostrophes affecting output.

My approach would be to use dict comprehension to map over the dictionary and replace every occurence of 'a' by '/a'.
I don't think there are significant performance improvements that can be done from there. You algorithm will be linear with regard to the total number of characters in the keys and items of the dict as you need to traverse the whole dictionary whatever the input.
living_beings= {"Reptile":"Snake","mammal":"whale", "Other":"bird"}
new_dict = {
kind.replace('a', '/a'): animal.replace('a', '/a') for kind, animal in living_beings.items()
}
# new_dict: {"Reptile":"Sn/ake","m/amm/al":"wh/ale", "Other":"bird"}
You could maybe optimize with a more convoluted solution that loops through the dict to mutate it instead of creating a new one, but in general I recommend not trying to do such things in Python. Just write good code, with good practices, and let Python do the optimization under the hood. After all this is what the Zen of Python tells us: Simple is better than complex.

This can be done quite efficiently using a regular expression match, e.g.:
import re
re_containsA = re.compile(r'.*a.*')
for key, word in worddict.items():
if re_containsA.match(word):
print(key)
The re.match object can then be used to find the location of the matched text.

How do I compare two strings using a for loop?

I'm building a simple email verifier. I need to compare the local-parts current letter to a list of valid characters. So essentially I'm asking how do I check to see if the current letter I'm on in local-part is equivalent to a letter in the ENTIRE list of valid chars. If it is a valid character, local-part will go to the next letter in its string and go through the list of valid characters to see if this too is and so on until it reaches the # symbol unless there isn't a valid character.
I'm fairly new to python so I don't know how nested for loops work.
for ch in local:
for ch in valChar:
if(ch ==ch) <----problem
This is what I currently have written for the loops. Is "ch" a variable or some type of syntax to represent char?

You don't need nested loop in this case, thanks to the in operator:
for c in local:
if c in valChar:
performvalidaction(c)
else:
denoteasinvalid(c)
What identifier to use (c, ch, or anything else) is pretty indifferent, I tend to use single-character identifiers for loop variables, but there's no rule saying that you must.
If you did have to use two nested loops, you'd just use different loop variables for the two loops.
In fact you don't even need one loop here (you could instead work e.g with Python's sets, for example) -- much less two -- but I guess using one loop is OK if it's clearer for you.

Let me explain the for loop for you:
for eachitem in file:
do something
eachitem is a variable of one specific value of a file/dictionairy etc..

ch is a variable, you can replace it with any valid identifier:
for local_ch in local:
for valChar_ch in valChar:
if(local_ch == valChar_ch): <----No problem

You need to validate an email address, i would use a regular expression:
\b[A-Z0-9._%+-]+#[A-Z0-9.-]+.[A-Z]{2,6}\b

Python: Custom sort a list of lists

I know this has been asked before, but I have not been able to find a solution.
I'm trying to alphabetize a list of lists according to a custom alphabet.
The alphabet is a representation of the Burmese script as used by Sgaw Karen in plain ASCII. The Burmese script is an alphasyllabary—a few dozen onsets, a handful of medial diacritics, and a few dozen rhymes that can be combined in thousands of different ways, each of which is a single "character" representing one syllable. The map.txt file has these syllables, listed in (Karen/Burmese) alphabetical order, but converted in some unknown way into ASCII symbols, so the first character is u>m;.Rf rather than က or [ka̰]. For example:
u>m;.Rf ug>m;.Rf uH>m;.Rf uX>m;.Rf uk>m;.Rf ul>m;.Rf uh>m;.Rf uJ>m;.Rf ud>m;.Rf uD>m;.Rf u->m;.Rf uj>m;.Rf us>m;.Rf uV>m;.Rf uG>m;.Rf uU>m;.Rf uS>m;.Rf u+>m;.Rf uO>m;.Rf uF>m;.Rf
c>m;.Rf cg>m;.Rf cH>m;.Rf cX>m;.Rf ck>m;.Rf cl>m;.Rf ch>m;.Rf cJ>m;.Rf cd>m;.Rf cD>m;.Rf c->m;.Rf cj>m;.Rf cs>m;.Rf cV>m;.Rf cG>m;.Rf cU>m;.Rf cS>m;.Rf c+>m;.Rf cO>m;.Rf cF>m;.Rf
Each list in the list of lists has, as its first element, a word of Sgaw Karen converted into ASCII symbols in the same way. For example:
[['u&X>', 'n', 'yard'], ['vk.', 'n', 'yarn'], ['w>ouDxD.', 'n', 'yawn'], ['w>wuDxD.', 'n', 'yawn']]
This is what I have so far:
def alphabetize(word_list):
alphabet = ''.join([line.rstrip() for line in open('map.txt', 'rb')])
word_list = sorted(word_list, key=lambda word: [alphabet.index(c) for c in word[0]])
return word_list
I would like to alphabetize word_list by the first element of each list (eg. 'u&X>', 'vk.'), according to the pattern in alphabet.
My code's not working yet and I'm struggling to understand the sorted command with lambda and the for loop.

First, if you're trying to look up the entire word[0] in alphabet, rather than each character individually, you shouldn't be looping over the characters of word[0]. Just use alphabet.index(word[0]) directly.
From your comments, it sounds like you're trying to look up each transliterated-Burmese-script character in word[0]. That isn't possible unless you can write an algorithm to split a word up into those characters. Splitting it up into the ASCII bytes of the transliteration doesn't help at all.
Second, you probably shouldn't be using index here. When you think you need to use index or similar functions, 90% of the time, that means you're using the wrong data structure. What you want here is a mapping (presumably why it's called map.txt), like a dict, keyed by words, not a list of words that you have to keep explicitly searching. Then, looking up a word in that dictionary is trivial. (It's also a whole lot more efficient, but the fact that it's easy to read and understand can be even more important.)
Finally, I suspect that your map.txt is supposed to be read as a whitespace-separated list of transliterated characters, and what you want to find is the index into that list for any given word.
So, putting it all together, something like this:
with open('map.txt', 'rb') as f:
mapping = {word: index for index, word in enumerate(f.read().split())}
word_list = sorted(word_list, key=lambda word: mapping[word[0]])
But, again, that's only going to work for one-syllable words, because until you can figure out how to split a word up into the units that should be alphabetized (in this case, the symbols), there is no way to make it work for multi-syllable words.
And once you've written the code that does that, I'll bet it would be pretty easy to just convert everything to proper Unicode representations of the Burmese script. Each syllable still takes 1-4 code points in Unicode—but that's fine, because the standard Unicode collation algorithm, which comes built-in with Python, already knows how to alphabetize things properly for that script, so you don't have to write it yourself.
Or, even better, unless this is some weird transliteration that you or your teacher invented, there's probably already code to translate between this format and Unicode, which means you shouldn't even have to write anything yourself.

wxPython/TextCtrl replacing a character within the first x lines of a string

I've scanned the questions here as well as the web and haven't found my answer, this is my first question and I'm a noobie to (wx)Python so go easy on me.
Using TextCtrl I'm trying to remove a single character within a string, this string will always start with the same set of characters but the rest of the string is freely editable by the user.
e.g
self.text=wx.TextCtrl(panel,-1"hello world,, today we're asking a question on stackoverflow, what would you ask?")
poor example but how would I find and remove the 11th(',') character so the sentence is more formatted without affecting the rest of the string?
I've tried standard python indexing but I get an error for that, I can successfully remove chunks of the string from the start outwards of the end inwards but I need only a single character removed.
Again, sorry for the poor terminology, as I said I'm fairly new to python so some of my terms may be a bit iffy.

self.text.SetValue(self.text.GetValue()[:10] + self.text.GetValue()[11:] )
maybe??
self.text.SetValue(self.text.GetValue().replace(",,",",")
maybe?
its not really clear what you are trying to accomplish here ...

Counting characters that print, not processed, in a string

Dealing with an annoying issue using foreign characters (ģ,č,ŗ,ļ,ā,ē,ū,ī,ņ,š,ķ,ž and their capitals). They all have length using len not equal to 1, for example len('ī') is 2 (it shows up as \xc4\xab when processing text). I would like a function that gives back 1 for all those characters. Any help?

Kudos to Robᵩ for the explanatory webpage. A concise solution to my problem:
def varlen(string):
return len(string.decode('utf-8'))