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python 3 parsing a semicolon separated very long string to remove each second element

I'm pretty new to python and are looking for a way to get the following result from a long string
reading in lines of a textfile where each line looks like this
; 2:55:12;PuffDG;66,81; Puff4OG;66,75; Puff3OG;35,38;
after dataprocessing the data shall be stored in another textfile with this data
short example
2:55:12;66,81;66,75;35,38;
the real string is much longer but always with the same pattern
; 2:55:12;PuffDG;66,81; Puff4OG;66,75; Puff3OG;35,38; Puff2OG;30,25; Puff1OG;29,25; PuffFB;23,50; ....
So this means remove leading semicolon
keep second element
remove third element
keep fourth element
remove fith element
keep sixth element
and so on
the number of elements can vary so I guess as a first step I have to parse the string to get the number of elements and then do some looping through the string and assign each part that shall be kept to a variable
I have tried some variations of the command .split() but with no success.
Would it be easier to store all elements in a list and then for-loop through the list keeping and dropping elements?
If Yes how would this look like so at the end I have stored a file with
lines like this
2:55:12 ; 66,81 ; 66,75 ; 35,38 ;
2:56:12 ; 67,15 ; 74;16 ; 39,15 ;
etc. ....
best regards Stefan

This solution works independently of the content between the semicolons
One line, though it's a bit messier:
result = ' ; '.join(string.split(';')[1::2])
Getting rid of lead semicolon:
Just slice it off!
string = string[2:]
Splitting by semicolon & every second element:
Given a string, we can split by semicolon:
arr = string.split(';')[1::2]
The [::2] means to slice out every second element, starting with index 1. This keeps all "even" elements (second, fourth, etcetera).
Resulting string
To produce the string result you want, simply .join:
result = ' ; '.join(arr)

A regex based solution, which operates on the original input:
inp = "; 2:55:12;PuffDG;66,81; Puff4OG;66,75; Puff3OG;35,38;"
output = re.sub(r'\s*[A-Z][^;]*?;', '', inp)[2:]
print(output)
This prints:
2:55:12;66,81;66,75;35,38;

This shows how to do it for one line of input if the same pattern repeats itself every time
input_str = "; 2:55:12;PuffDG;66,81; Puff4OG;66,75; Puff3OG;35,38;"
f = open('output.txt', 'w') # open text to write to
output_list = input_str.split(';')[1::2] # create list with numbers of interest
# write to file
for out in output_list:
f.write(f"{out.strip()} ; ")
# end line
f.write("\n")

thank you very much for the quick response. You are awesome.
Your solutions are very comact.
In the meantime I found another solution but this solution needs more lines of code
best regards Stefan
I'm not familiar with how to insert code as a code-section properly
So I add it as plain text
fobj = open(r"C:\Users\Stefan\AppData\Local\Programs\Python\Python38-32\Heizung_2min.log")
wobj = open(r"C:\Users\Stefan\AppData\Local\Programs\Python\Python38-32\Heizung_number_2min.log","w")
for line in fobj:
TextLine = fobj.readline()
print(TextLine)
myList = TextLine.split(';')
TextLine = ""
for index, item in enumerate(myList):
if index % 2 == 1:
TextLine += item
TextLine += ";"
TextLine += '\n'
print(TextLine)
wobj.write(TextLine)
fobj.close()
wobj.close()`

Parsing a list of lists and manipulating it in place

So I have a list of lists that I need to parse through and manipulate the contents of. There are strings of numbers and words in the sublists, and I want to change the numbers into integers. I don't think it's relevant but I'll mention it just in case: my original data came from a CSV that I split on newlines, and then split again on commas.
What my code looks like:
def prep_data(data):
list = data.split('\n') #Splits data on newline
list = list[1:-1] #Gets rid of header and last row, which is an empty string
prepped = []
for x in list:
prepped.append(x.split(','))
for item in prepped: #Converts the item into an int if it is able to be converted
for x in item:
try:
item[x] = int(item[x])
except:
pass
return prepped
I tried to loop through every sublist in prepped and change the type of the values in them, but it doesn't seem like the loop does anything as the prep_data returns the same thing as it did before I implemented that for loop.

I think I see what is wrong, you are thinking python is more generous with it's assignment than it actually is.
def prep_data(data):
list = data.split('\n') #Splits data on newline
list = list[1:-1] #Gets rid of header and last row, which is an empty string
prepped = []
for x in list:
prepped.append(x.split(','))
for i in prepped: #Converts the item into an int if it is able to be converted
item = prepped[i]
for x in item:
try:
item[x] = int(item[x])
except:
pass
prepped[i] = item
return prepped
I can't run this on the machine I'm on right now but it seems the problem is that "prepped" wasn't actually receiving any new assignments, you were just changing values in the sub array "item"

I'm not sure about your function, because maybe I didn't understand your income data, but you could try something like the following because if you only pass, you could lose string or weird data:
def parse_data(raw_data):
data_lines = raw_data.split('\n') #Splits data on newline
data_rows_without_header = data_lines[1:-1] #Gets rid of header and last row, which is an empty string
parsed_date = []
for raw_row in data_rows_without_header:
splited_row = raw_line.split(',')
parsed_row = []
for value in splited_row:
try:
parsed_row.append(int(value)
except:
print("The value '{}' is not castable".format(value))
parsed_row.append(value) # if cast fails, add the string as it is
parsed_date.append(parsed_row)
return parsed_date

How can I Split a list in python to get a new list with elements to the left of the delimiter instead of the right

I want to split this python list (originalList):
['"car_type":"STANDARD","price":725842',
'"car_type":"LUXURY","price":565853',
'"car_type":"PEOPLE_CARRIER","price":239081',
'"car_type":"LUXURY_PEOPLE_CARRIER","price":661624',
'"car_type":"MINIBUS","price":654172']
to give me this list (pricesList):
[725842, 565853, 239081, 661624, 654172]
I tried this line of code below to split the list named originalList:
pricesList = [i.split("price:")[0] for i in originalList]
The outcome is a list with the same number of elements, but each element contains the car_type only, in short the splitting has removed everything to the left of the delimiter. How can I change my code above or even replace to obtain in the new list elements with the values to the left of the delimiter and everything to the right removed?

You forget the double-quotes " that are part of your delimiter, then pick the wrong index (0) which is before the split, and finally, you do not cast to int. You can do the following to get the desired output:
>>> [int(i.split('"price":')[-1]) for i in originalList]
[725842, 565853, 239081, 661624, 654172]

schwobaseggl answer is good, here is a possible alternative using json library (I guess original list comes from json processing)
import json
list(map(lambda x:json.loads('{'+x+'}')['price'],originalList))

You can try:
import json
n = ['"car_type":"STANDARD","price":725842',
'"car_type":"LUXURY","price":565853',
'"car_type":"PEOPLE_CARRIER","price":239081',
'"car_type":"LUXURY_PEOPLE_CARRIER","price":661624',
'"car_type":"MINIBUS","price":654172']
print [json.loads("{"+str(i)+"}")["price"] for i in n]

Another way of doing it:
pricesList = [int(originalList[i].split(",")[1].split(":")[1]) for i in range(0,len(l1))]

Solution
If you change to .split(':') you can just take the [-1] item, that will represent the numbers at the end
lista = [
'"car_type":"STANDARD","price":725842',
'"car_type":"LUXURY","price":565853',
'"car_type":"PEOPLE_CARRIER","price":239081',
'"car_type":"LUXURY_PEOPLE_CARRIER","price":661624',
'"car_type":"MINIBUS","price":654172'
]
new_lista = []
for i in range(len(lista)):
lista[i] = lista[i].split(':')
new_lista.append(lista[i][-1])
print(new_lista)
Output
(xenial)vash#localhost:~/python$ python3.7 split.py
['725842', '565853', '239081', '661624', '654172']

Remove text:u from strings in python

I am using xlrd library to import values from excel file to python list.
I have a single column in excel file and extracting data row wise.
But the problem is the data i am getting in list is as
list = ["text:u'__string__'","text:u'__string__'",.....so on]
How can i remove this text:u from this to get natural list with strings ?
code here using python2.7
book = open_workbook("blabla.xlsx")
sheet = book.sheet_by_index(0)
documents = []
for row in range(1, 50): #start from 1, to leave out row 0
documents.append(sheet.cell(row, 0)) #extract from first col
data = [str(r) for r in documents]
print data

Iterate over items and remove extra characters from each word:
s=[]
for x in list:
s.append(x[7:-1]) # Slice from index 7 till lastindex - 1

If that's the standard input list you have, you can do it with simple split
[s.split("'")[1] for s in list]
# if your string itself has got "'" in between, using regex is always safe
import re
[re.findall(r"u'(.*)'", s)[0] for s in list]
#Output
#['__string__', '__string__']

I had the same problem. Following code helped me.
list = ["text:u'__string__'","text:u'__string__'",.....so on]
for index, item in enumerate(list):
list[index] = list[index][7:] #Deletes first 7 xharacters
list[index] = list[index][:-1] #Deletes last character

python - matching string and replacing

I have a file i am trying to replace parts of a line with another word.
it looks like bobkeiser:bob123#bobscarshop.com:0.0.0.0.0:23rh32o3hro2rh2:234212
i need to delete everything but bob123#bobscarshop.com, but i need to match 23rh32o3hro2rh2 with 23rh32o3hro2rh2:poniacvibe , from a different text file and place poniacvibe infront of bob123#bobscarshop.com
so it would look like this bob123#bobscarshop.com:poniacvibe
I've had a hard time trying to go about doing this, but i think i would have to split the bobkeiser:bob123#bobscarshop.com:0.0.0.0.0:23rh32o3hro2rh2:234212 with data.split(":") , but some of the lines have a (:) in a spot that i don't want the line to be split at, if that makes any sense...
if anyone could help i would really appreciate it.

ok, it looks to me like you are using a colon : to separate your strings.
in this case you can use .split(":") to break your strings into their component substrings
eg:
firststring = "bobkeiser:bob123#bobscarshop.com:0.0.0.0.0:23rh32o3hro2rh2:234212"
print(firststring.split(":"))
would give:
['bobkeiser', 'bob123#bobscarshop.com', '0.0.0.0.0', '23rh32o3hro2rh2', '234212']
and assuming your substrings will always be in the same order, and the same number of substrings in the main string you could then do:
firststring = "bobkeiser:bob123#bobscarshop.com:0.0.0.0.0:23rh32o3hro2rh2:234212"
firstdata = firststring.split(":")
secondstring = "23rh32o3hro2rh2:poniacvibe"
seconddata = secondstring.split(":")
if firstdata[3] == seconddata[0]:
outputdata = firstdata
outputdata.insert(1,seconddata[1])
outputstring = ""
for item in outputdata:
if outputstring == "":
outputstring = item
else
outputstring = outputstring + ":" + item
what this does is:
extract the bits of the strings into lists
see if the "23rh32o3hro2rh2" string can be found in the second list
find the corresponding part of the second list
create a list to contain the output data and put the first list into it
insert the "poniacvibe" string before "bob123#bobscarshop.com"
stitch the outputdata list back into a string using the colon as the separator
the reason your strings need to be the same length is because the index is being used to find the relevant strings rather than trying to use some form of string type matching (which gets much more complex)
if you can keep your data in this form it gets much simpler.
to protect against malformed data (lists too short) you can explicitly test for them before you start using len(list) to see how many elements are in it.
or you could let it run and catch the exception, however in this case you could end up with unintended results, as it may try to match the wrong elements from the list.
hope this helps
James
EDIT:
ok so if you are trying to match up a long list of strings from files you would probably want something along the lines of:
firstfile = open("firstfile.txt", mode = "r")
secondfile= open("secondfile.txt",mode = "r")
first_raw_data = firstfile.readlines()
firstfile.close()
second_raw_data = secondfile.readlines()
secondfile.close()
first_data = []
for item in first_raw_data:
first_data.append(item.replace("\n","").split(":"))
second_data = []
for item in second_raw_data:
second_data.append(item.replace("\n","").split(":"))
output_strings = []
for item in first_data:
searchstring = item[3]
for entry in second_data:
if searchstring == entry[0]:
output_data = item
output_string = ""
output_data.insert(1,entry[1])
for data in output_data:
if output_string == "":
output_string = data
else:
output_string = output_string + ":" + data
output_strings.append(output_string)
break
for entry in output_strings:
print(entry)
this should achieve what you're after and as prove of concept will print the resulting list of stings for you.
if you have any questions feel free to ask.
James
Second edit:
to make this output the results into a file change the last two lines to:
outputfile = open("outputfile.txt", mode = "w")
for entry in output_strings:
outputfile.write(entry+"\n")
outputfile.close()