I have an input, which is a tuple of strings, encoded in a1z26 cipher: numbers from 1 to 26 represent alphabet letters, hyphens represent same word letters and spaces represent an space between words.
For example:
8-9 20-8-5-18-5 should translate to 'hi there'
Let's say that the last example is a tuple in a var called string
string = ('8-9','20-8-5-18-5')
The first thing I find logical is convert the tuple into a list using
string = list(string)
so now
string = ['8-9','20-8-5-18-5']
The problem now is that when I iterate over the list to compare it with a dictionary which has the translated values, double digit numbers are treated as one, so instead of, for example, translating '20' it translate '2' and then '0', resulting in the string saying 'hi bheahe' (2 =b, 1 = a and 8 = h)
so I need a way to convert the list above to the following
list
['8','-','9',' ','20','-','8','-','5','-','18','-','5',]
I've already tried various codes using
list(),
join() and
split()
But it ends up giving me the same problem.
To sum up, I need to make any given list (converted from the input tuple) into a list of characters that takes into account double digit numbers, spaces and hyphens altogether
This is what I've got so far. (The last I wrote) The input is further up in the code (string)
a1z26 = {'1':'A', '2':'B', '3':'C', '4':'D', '5':'E', '6':'F', '7':'G', '8':'H', '9':'I', '10':'J', '11':'K', '12':'L', '13':'M', '14':'N', '15':'O', '16':'P', '17':'Q', '18':'R', '19':'S', '20':'T', '21':'U', '22':'V', '23':'W', '24':'X', '25':'Y', '26':'Z', '-':'', ' ' : ' ', ', ' : ' '}
translation = ""
code = list(string)
numbersarray1 = code
numbersarray2 = ', '.join(numbersarray1)
for char in numbersarray2:
if char in a1z26:
translation += a1z26[char]
There's no need to convert the tuple to a list. Tuples are iterable too.
I don't think the list you name is what you actually want. You probably want a 2d iterable (not necessarily a list, as you'll see below we can do this in one pass without generating an intermediary list), where each item corresponds to a word and is a list of the character numbers:
[[8, 9], [20, 8, 5, 18, 5]]
From this, you can convert each number to a letter, join the letters together to form the words, then join the words with spaces.
To do this, you need to pass a parameter to split, to tell it how to split your input string. You can achieve all of this with a one liner:
plaintext = ' '.join(''.join(num_to_letter[int(num)] for num in word.split('-'))
for word in ciphertext.split(' '))
This does exactly the splitting procedure as described above, and then for each number looks into the dict num_to_letter to do the conversion.
Note that you don't even need this dict. You can use the fact that A-Z in unicode is contiguous so to convert 1-26 to A-Z you can do chr(ord('A') + num - 1).
You don't really need hypens, am I right?
I suggest you the following approach:
a = '- -'.join(string).split('-')
Now a is ['8', '9', ' ', '20', '8', '5', '18', '5']
You can then convert each number to the proper character using your dictionary
b = ''.join([a1z26[i] for i in a])
Now b is equal to HI THERE
I think, it's better to apply regular expressions there.
Example:
import re
...
src = ('8-9', '20-8-5-18-5')
res = [match for tmp in src for match in re.findall(r"([0-9]+|[^0-9]+)", tmp + " ")][:-1]
print(res)
Result:
['8', '-', '9', ' ', '20', '-', '8', '-', '5', '-', '18', '-', '5']
using regex here is solution
import re
string = '8-9 20-8-5-18-5'
exp=re.compile(r'[0-9]+|[^0-9]+')
data= exp.findall(string)
print(data)
output
['8', '-', '9', ' ', '20', '-', '8', '-', '5', '-', '18', '-', '5']
if you want to get hi there from the input string , here is a method (i am assuming all character are in uppercase):
import re
string = '8-9 20-8-5-18-5'
exp=re.compile(r'[0-9]+|[^0-9]+')
data= exp.findall(string)
new_str =''
for i in range(len(data)):
if data[i].isdigit():
new_str+=chr(int(data[i])+64)
else:
new_str+=data[i]
result = new_str.replace('-','')
output:
HI THERE
You could also try this itertools solution:
from itertools import chain
from itertools import zip_longest
def separate_list(lst, delim, sep=" "):
result = []
for x in lst:
chars = x.split(delim) # 1
pairs = zip_longest(chars, [delim] * (len(chars) - 1), fillvalue=sep) # 2, 3
result.extend(list(chain.from_iterable(pairs))) # 4
return result[:-1] # 5
print(separate_list(["8-9", "20-8-5-18-5"], delim="-"))
Output:
['8', '-', '9', ' ', '20', '-', '8', '-', '5', '-', '18', '-', '5']
Explanation of above code:
Split each string by delimiter '-'.
Create interspersing delimiters.
Create pairs of characters and separators with itertools.zip_longest.
Extend flattened pairs to result list with itertools.chain.from_iterable.
Remove trailing ' ' from result list added.
You could also create your own intersperse generator function and apply it twice:
from itertools import chain
def intersperse(iterable, delim):
it = iter(iterable)
yield next(it)
for x in it:
yield delim
yield x
def separate_list(lst, delim, sep=" "):
return list(
chain.from_iterable(
intersperse(
(intersperse(x.split(delim), delim=delim) for x in lst), delim=[sep]
)
)
)
print(separate_list(["8-9", "20-8-5-18-5"], delim="-"))
# ['8', '-', '9', ' ', '20', '-', '8', '-', '5', '-', '18', '-', '5']
Related
Im trying to use replace to get rid of white space but it is not working. What am i doing wrong?
import re
list = ('255 +1', '282 +5', '255 + 3', '5 - 2',)
for i in list:
# seperating the numbers in to a list
nums = re.split(r'[+,-]\s*', i)
#getting rid of white space in list
for num in nums:
num.replace(' ', '')
print(nums)
this is the output. in the first part of the lists it is not getting rid of it.
['255 ', '1']
['282 ', '5']
['255 ', '3']
['5 ', '2']
Strings are immutable objects in python, meaning their values cannot be changed. If you were to use the replace method you would have to set that to a new variable.
For example, if you wanted to use replace you would need to initialize a new String Variable and set it equal to num.replace(' ', ''), or alternatively use the strip() method with no parameters to remove trailing and leading white spaces.
If you wanted to reflect a new string without whitespaces...
myString = 'thisString ' #Notice the trailing whitespace
newString = myString.strip() #Removes whitespace and stores in newString
print(newString) #This would output the string with no white space
(1) we can use regex in the first step to just extract all numbers. this results in s list of 8 elements: ['255', '1', '282', '5', '255', '3', '5', '2']
(2) we create an index by using range() with step 2
(3) we use the index from previous step to create chunks (length 2) of pairs by using a slice and append them to a list
import re
regex = r"(\d+)"
test_str = ("'255 +1', '282 +5', '255 + 3', '5 - 2'\n")
matches = re.findall(regex, test_str) # (1)
res = []
for ind in range(0, len(matches), 2): # (2)
res.append(matches[ind:ind + 2]) # (3)
print(res)
output is [['255', '1'], ['282', '5'], ['255', '3'], ['5', '2']]
can any of you help me to identify what am I doing wrong? I know this might be simple but I
am new to programming and Python. I need to return ['*', '2', '3', '*', '5']. Instead of that I am
getting much more values within the list.
Test to replace values in a List
repl_list = [1, 2, 3, 1, 5]
str_repl_list = str(repl_list)
# print('This is the list to replace: ' + str_repl_list)
# print(type(str_repl_list[0]))
new_str_list = []`enter code here`
print(new_str_list)
for item in str_repl_list:
replacement = item.replace('1', '*')
new_str_list.append(replacement)
for index, char in enumerate(new_str_list):
print(index, char) # This is to identify what information is being taken as par of the new list
when you do a str(repl_list), the outpt is a string '[1, 2, 3, 1, 5]', not a list of strings, so if you iterate through str_repl_list you will get
1
,
2
,
3
,
1
,
5
]
Instead you can avoid that step and convert each item to string inside your for loop (str(item))
repl_list = [1, 2, 3, 1, 5]
new_str_list = []
for item in repl_list:
replacement = str(item).replace('1', '*')
new_str_list.append(replacement)
>>> print(new_str_list)
>>> ['*', '2', '3', '*', '5']
you can also use list coprehension
>>> print(['*' if x == 1 else str(x) for x in repl_list])
>>> ['*', '2', '3', '*', '5']
Instead of converting each item to string, you are converting the entire list into a string. Instead try this list comprehension:
str_repl_list = [str(i) for i in str_list]
This will go through each item and convert it into a string, then store it in the new list.
since you are appending each element in the list new_str_list, to see the desired result you need to print them together, so you need to join them in a string and add all element in the string.
so to see the desired result, you just need to add all elment together
which can be done as
str_list_final = ''.join(new_str_list)
note that the final two numbers of this pattern for example FBXASC048 are ment to be ascii code for numbers (0-9)
input example list ['FBXASC048009Car', 'FBXASC053002Toy', 'FBXASC050004Human']
result example ['1009Car', '5002Toy', '2004Human']
what is the proper way to searches for any of these pattern in an input list
num_ascii = ['FBXASC048', 'FBXASC049', 'FBXASC050', 'FBXASC051', 'FBXASC052', 'FBXASC053', 'FBXASC054', 'FBXASC055', 'FBXASC056', 'FBXASC057']
and then replaces the pattern found with one of the items in the conv list but not randomally
because each element in the pattern list equals only one element in the conv_list
conv_list = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
this is the solution in mind:
it has two part
1st part--> is to find for ascii pattern[48, 49, 50, 51, 52, 53, 54, 55, 56,57]
and then replace those with the proper decimal matching (0-9)
so we will get new input list will be called input_modi_list that has ascii replaced with decimal
2nd part-->another process to use fixed pattern to replace using replace function which is this 'FBXASC0'
new_list3
for x in input_modi_list:
y = x.replace('FBXASC0', '')
new_list3.append(new_string)
so new_list3 will have the combined result of the two parts mentioned above.
i don't know if there would be a simplar solution or a better one maybe using regex
also note i don't have any idea on how to replace ascii with decimal for a list of items
I think this should do the trick:
import re
input_list = ['FBXASC048009Car', 'FBXASC053002Toy', 'FBXASC050004Human']
pattern = re.compile('FBXASC(\d{3,3})')
def decode(match):
return chr(int(match.group(1)))
result = [re.sub(pattern, decode, item) for item in input_list]
print(result)
Now, there is some explanation due:
1- the pattern object is a regular expression that will match any part of a string that starts with 'FBXASC' and ends with 3 digits (0-9). (the \d means digit, and {3,3} means that it should occur at least 3, and at most 3 times, i.e. exactly 3 times). Also, the parenthesis around \d{3,3} means that the three digits matched will be stored for later use (explained in the next part).
2- The decode function receives a match object, uses .group(1) to extract the first matched group (which in our case are the three digits matched by \d{3,3}), then uses the int function to parse the string into an integer (for example, convert '048' to 48), and finally uses the chr function to find which character has that ASCII-code. (for example chr(48) will return '0', and chr(65) will return 'A')
3- The final part applies the re.sub function to all elements of list which will replace each occurrence of the pattern you described (FBXASC048[3-digits]) with it's corresponding ASCII character.
You can see that this solution is not limited only to your specific examples. Any number can be used as long as it has a corresponding ASCII character recognized by the chr function.
But, if you do want to limit it just to the 48-57 range, you can simply modify the decode function:
def decode(match):
ascii_code = int(match.group(1))
if ascii_code >= 48 and ascii_code <= 57:
return chr(ascii_code)
else:
return match.group(0) # returns the entire string - no modification
This is how I would do it.
make the regex pattern by simply joining the strings with |:
>>> num_ascii = ['FBXASC048', 'FBXASC049', 'FBXASC050', 'FBXASC051', 'FBXASC052', 'FBXASC053', 'FBXASC054', 'FBXASC055', 'FBXASC056', 'FBXASC057']
>>> conv_list = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
>>> regex_pattern = '|'.join(num_ascii)
>>> regex_pattern
'FBXASC048|FBXASC049|FBXASC050|FBXASC051|FBXASC052|FBXASC053|FBXASC054|FBXASC055
|FBXASC056|FBXASC057'
make a look-up dictionary by simply zipping the two lists:
>>> conv_table = dict(zip(num_ascii, conv_list))
>>> conv_table
{'FBXASC048': '0', 'FBXASC049': '1', 'FBXASC050': '2', 'FBXASC051': '3', 'FBXASC
052': '4', 'FBXASC053': '5', 'FBXASC054': '6', 'FBXASC055': '7', 'FBXASC056': '8
', 'FBXASC057': '9'}
iterate over the data and replace the matched string with the corresponding digit:
>>> import re
>>> result = []
>>> for item in ['FBXASC048009Car', 'FBXASC053002Toy', 'FBXASC050004Human']:
... m = re.match(regex_pattern, item)
... matched_string = m[0]
... digit = (conv_table[matched_string])
... print(f'replacing {matched_string} with {digit}')
... result.append(item.replace(matched_string, digit))
...
replacing FBXASC048 with 0
replacing FBXASC053 with 5
replacing FBXASC050 with 2
>>> result
['0009Car', '5002Toy', '2004Human']
I would like to split a string into sections of numbers and sections of text/symbols
my current code doesn't include negative numbers or decimals, and behaves weirdly, adding an empty list element on the end of the output
import re
mystring = 'AD%5(6ag 0.33--9.5'
newlist = re.split('([0-9]+)', mystring)
print (newlist)
current output:
['AD%', '5', '(', '6', 'ag ', '0', '.', '33', '--', '9', '.', '5', '']
desired output:
['AD%', '5', '(', '6', 'ag ', '0.33', '-', '-9.5']
Your issue is related to the fact that your regex captures one or more digits and adds them to the resulting list and digits are used as a delimiter, the parts before and after are considered. So if there are digits at the end, the split results in the empty string at the end to be added to the resulting list.
You may split with a regex that matches float or integer numbers with an optional minus sign and then remove empty values:
result = re.split(r'(-?\d*\.?\d+)', s)
result = filter(None, result)
To match negative/positive numbers with exponents, use
r'([+-]?\d*\.?\d+(?:[eE][-+]?\d+)?)'
The -?\d*\.?\d+ regex matches:
-? - an optional minus
\d* - 0+ digits
\.? - an optional literal dot
\d+ - one or more digits.
Unfortunately, re.split() does not offer an "ignore empty strings" option. However, to retrieve your numbers, you could easily use re.findall() with a different pattern:
import re
string = "AD%5(6ag0.33-9.5"
rx = re.compile(r'-?\d+(?:\.\d+)?')
numbers = rx.findall(string)
print(numbers)
# ['5', '6', '0.33', '-9.5']
As mentioned here before, there is no option to ignore the empty strings in re.split() but you can easily construct a new list the following way:
import re
mystring = "AD%5(6ag0.33--9.5"
newlist = [x for x in re.split('(-?\d+\.?\d*)', mystring) if x != '']
print newlist
output:
['AD%', '5', '(', '6', 'ag', '0.33', '-', '-9.5']
I want to split the string
" 510 -9999999 9 99 12 5 [3, 0] [] [6] "
(which contains more or less random numbers of whitespaces between the entries) into it's component parts, including the lists within the string. I can get to this
['510', '-9999999', '9', '99', '12', '5', '[3,', '0]', '[]', '[6]']
through using split and replace. However, I then want to reconstitute the lists within the original string so that I can get to
['510', '-9999999', '9', '99', '12', '5', '[3,0]', '[]', '[6]'].
The real problem is that this string is one of many and the lists may contain many, or no components so I have to deal with this is a general way.
I could potentially search for '[', then search for ']' to close up the list but, as I don't know the length of any of the lists going in, this seems an inefficient way of doing things.
Any help greatly appreciated!
There is always regex, but you can do it on the cheap like this
>>> import shlex
>>> shlex.split(s.replace('[','"[').replace(']',']"'))
['510', '-9999999', '9', '99', '12', '5', '[3, 0]', '[]', '[6]']
The proper solution would be to use pyparsing module, or even better to control the input source to give you something more sensible like json.
If lists aren't nested, you can try this:
def mysplit (a):
return re.split(' +', re.sub('\\[(.*?)\\]', lambda m: '[{}]'.format(m.groups()[0].replace(' ', '')), a))
If lists can't be nested then I think it is possible to preprocess string with:
s = " 510 -9999999 9 99 12 5 [3, 0] [] [6] "
opened = False
s_new = ""
for i in s:
if i == "[":
opened = True
if i == "]":
opened = False
if not opened or (opened and i != " "):
s_new += i
And then split it into list:
l = s_new.split()