Extract digits from string with consecutive digit characters - python

I cannot use Regular Expressions or library :(. I need to extract all digits from an alphanumeric string. Each consecutive sequence of digits (we can call "temperature") is precluded by a (+, -, or *) and will be considered as a single number (all are integers, no float). There are other non digit characters in the string that can be ignored. I need to extract each "temperature" into a data structure.
Example String "BARN21+77-48CDAIRY87+56-12" yields [21, 77, 48, 87, 56, 12]
The data string can be many many magnitudes larger.
All solutions I can find assume there is only 1 sequence of digits (temperature) in the string or that the (temperatures) are separated by a space/delimiter. I was able to get working by iterating through string and adding a space before and after each digit sequence and then using split but that feels like cheating. I wonder if you professionals distort data for a happy solution??
incoming data "BARN21+77-48CDAIRY87+56-12"
temp is what I change data to
temp = "BARN* 21 + 77 - 48 DAIRY* 87 + 56 - 12"
result = [int(i)
for i in temp.split()
if i.isdigit()]
print("The result ", result)
The result [21, 77, 48, 87, 56, 12]

Here is a version which does not use regular expressions:
inp = "BARN21+77-48CDAIRY87+56-12"
inp = ''.join(' ' if not ch.isdigit() else ch for ch in inp).strip()
nums = inp.split()
print(nums) # ['21', '77', '48', '87', '56', '12']
If regex be available for you, we can use re.findall with the regex pattern \d+:
inp = "BARN21+77-48CDAIRY87+56-12"
nums = re.findall(r'\d+', inp)
print(nums) # ['21', '77', '48', '87', '56', '12']

Related

python split string using alphabet to get only numerical values

Using python 3.8
Given str = A11B11C32D34,....
I want to split it into [11, 11, 32, 34 ...]. Meaning split using alphabets. How could I do this?
Thanks in advance!
Check with
s= 'A11B11C32D34'
s
Out[388]: 'A11B11C32D34'
import re
re.findall(r'\d+', s)
Out[390]: ['11', '11', '32', '34']
I might also suggest using a regex split approach here:
inp = "A11B11C32D34"
nums = [x for x in re.split(r'\D+', inp) if x]
print(nums) # ['11', '11', '32', '34']
The idea here is to split the string on any one or more collection of non digit characters. I also use a list comprehension to remove any leading/trailing empty entries in the output from re.split which might arise due to the string starting/ending with a non digit character.

how to find the matching pattern for an input list and then replace the found pattern with the proper pattern conversion using python

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']

How to remove alphabets and extract numbers using regex in python?

How to remove alphabets and extract numbers using regex in python?
import re
l=["098765432123 M","123456789012"]
s = re.findall(r"(?<!\d)\d{12}", l)
print(s)
Expected Output:
123456789012
If all you want is to have filtered list, consisting elements with pure digits, use filter with str.isdigit:
list(filter(str.isdigit, l))
Or as #tobias_k suggested, list comprehension is always your friend:
[s for s in l if s.isdigit()]
Output:
['123456789012']
I would suggest to use a negative lookahead assertion, if as stated you want to use regex only.
l=["098765432123 M","123456789012"]
res=[]
for a in l:
s = re.search(r"(?<!\d)\d{12}(?! [a-zA-Z])", a)
if s is not None:
res.append(s.group(0))
The result would then be:
['123456789012']
To keep only digits you can do re.findall('\d',s), but you'll get a list:
s = re.findall('\d', "098765432123 M")
print(s)
> ['0', '9', '8', '7', '6', '5', '4', '3', '2', '1', '2', '3']
So to be clear, you want to ignore the whole string if there is a alphabetic character in it? Or do you still want to extract the numbers of a string with both numbers and alphabetic characters in it?
If you want to find all numbers, and always find the longest number use this:
regex = r"\d+"
matches = re.finditer(regex, test_str, re.MULTILINE)
\d will search for digits, + will find one or more of the defined characters, and will always find the longest consecutive line of these characters.
If you only want to find strings without alphabets:
import re
regex = r"[a-zA-Z]"
test_str = ("098765432123 M", "123456789012")
for x in test_str:
if not re.search(regex, x):
print(x)

Separate each item of a list in an specific way

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']

Split and retain character of split python

I want to split a string bases on 4 criteria [ a, p, :, -], and additionally convert string with only numbers into integers.
import re
DATA = "12:30pm-12:00am"
print (re.split('[-:ap]',DATA))
Input string : "12:30pm-12:00am"
Desired output array:
[ 12, ":", 30, "pm", "-", 12, ":", 00, "am"]
[Full disclosure] This is from a coderbyte challenge. I am sorry if this is so noob it offends you, thank you for your patience.
filter(None, re.split('(-|:|am|pm)', '12:30pm-12:00am'))
Start with this, it will guide you to the solutions, this will give you the desired output to start with:
['12', ':', '30', 'pm', '-', '12', ':', '00', 'am']
Note that the input is string, and in your post you posted the numbers as integers.

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