CODEWITHSUNDEEP
python
Stefan
Stefan

Reputation: 957

Splitting list of strings based on index

My data is generated in not quite a useful manner with first a few spaces, then the index number (1-12 in this example) and then the actual value associated with the index. What I would like is to split the string in two lists: 1 list with the indices and 1 list with the values. I've written the following code that works for what I want. However, it seems cumbersome and takes many seconds to run for a data set of a few thousand rows. Is there a way to speed this up for large data sets?

data = ['         11.814772E3',
 '         2-1.06152E3',
 '         33.876477E1',
 '         4-2.65704E3',
 '         51.141537E4',
 '         61.378482E4',
 '         71.401565E4',
 '         86.782599E3',
 '         9-1.22921E3',
 '        103.400054E3',
 '        111.558086E3',
 '        121.017818E4']

values_total = [] #without empty strings
location     = [] #index when id goes to value
ids          = [] #Store ids
values       = [] #Store values

step_array = np.linspace(1,1E3,1E3) #needed to calculate index values

for i in range(len(data)):

    #Check how many indices have to be removed
    location.append([])
    location[i].append(int(math.log10(step_array[i]))+1)

    #Store values after empty strings
    for j in range(len(data[i])):
        values_total.append([])
        if data[i][j] != ' ':
            values_total[i].append(data[i][j])

    #Split list based on calculated lengths
    ids.append(values_total[i][:location[i][0]])
    values.append(values_total[i][location[i][0]:])

Upvotes: 0

Views: 49

Answers (1)

oskros
oskros

Reputation: 3285

You could try with the code below:

indices = []
vals = []
for i, d in enumerate(data, 1):  # enumerate starting from 1, so we know current index
    tmp = d.strip()  # remove whitespace
    split_idx = len(str(i))  # figure out the length of the current index
    indices.append(i)  # current index
    vals.append(float(tmp[split_idx:]))  # everything after current index length

Upvotes: 1

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