Getting the integer value from a list of strings-CodePudding

I have a string list which looks like this:

Loops = ['Loop 0 from point number 0 to 965', 
         'Loop 1 from point number 966 to 1969',
         'Loop 2 from point number 1970 to 2961']

I am trying to get the range of the point numbers from the above list of strings.

For example: LoopStart1 = 0, LoopEnd1 = 965, LoopStart2 = 966, LoopEnd2 = 1969

I can imagine using for loops or string slicing to do that but how exactly / which commands should I use to specifically take the point numbers (integers) from these list of strings? Since the numbers each have different lengths.

Thanks in advance!

CodePudding user response：

You can use regex to do it. Then create a dictionary to store all values:

import re

Loops = ['Loop 0 from point number 0 to 965', 
         'Loop 1 from point number 966 to 1969',
         'Loop 2 from point number 1970 to 2961']
d = {}
for index, value in enumerate(Loops):
    m = re.findall(r'\d  to \d ', value) 
    m = [i.split('to') for i in m]
    d[f'LoopStart{index 1}'] = int(m[0][0])
    d[f'LoopEnd{index 1}'] = int(m[0][-1])

print(d)

Output:

{'LoopStart1': 0, 'LoopEnd1': 965, 'LoopStart2': 966, 'LoopEnd2': 1969, 'LoopStart3': 1970, 'LoopEnd3': 2961}

Explanation:

This line gets the index and item of that loop. i.e. index = 0,1,2... and value = 'Loop 0 from...', 'Loop 1 from ....'

for index, value in enumerate(Loops):

This line finds all the strings which start with a number, have 'to' in between, and end with a number.

m = re.findall(r'\d  to \d ', value)

This line splits the m string by to.

m = [i.split('to') for i in m]

This line adds the loop item with starting value in a dictionary called d

d[f'LoopStart{index 1}'] = int(m[0][0])

This line adds the loop item with an ending value in a dictionary called d

d[f'LoopEnd{index 1}'] = int(m[0][-1])

Also, this f'{value}' of creating strings is called f-strings.

CodePudding user response：

You can use a nested list comprehension:

pl=[f'LoopStart{ln 1} = {ls}, LoopEnd{ln 1} = {le}' 
        for ln, ls, le in [[int(w) for w in line.split() if w.isnumeric()] 
            for line in Loops]]


>>> print(', '.join(pl))
LoopStart1 = 0, LoopEnd1 = 965, LoopStart2 = 966, LoopEnd2 = 1969, LoopStart3 = 1970, LoopEnd3 = 2961

Breaking that down, this part makes sub lists of the numbers found:

>>> sl=[[int(w) for w in line.split() if w.isnumeric()] 
...                     for line in Loops]
>>> sl
[[0, 0, 965], [1, 966, 1969], [2, 1970, 2961]]

Then this part makes a list of formatted strings from the values in those sublists:

>>> pl=[f'LoopStart{ln 1} = {ls}, LoopEnd{ln 1} = {le}' for ln, ls, le in sl]
>>> pl
['LoopStart1 = 0, LoopEnd1 = 965', 'LoopStart2 = 966, LoopEnd2 = 1969', 'LoopStart3 = 1970, LoopEnd3 = 2961']

Then join together:

>>> ', '.join(pl)
'LoopStart1 = 0, LoopEnd1 = 965, LoopStart2 = 966, LoopEnd2 = 1969, LoopStart3 = 1970, LoopEnd3 = 2961'