how to create 2d array in python if we know number of rows,and number of columns depends on some condition?

Question

My array maximum dimension could be 2x27,but number of columns could be lower than 27.Number of columns depends on some condition.Is good solution to initialize array 2x27 and then delete unnecessary columns or has more elegant way to do this?

Answer 1

For so few elements use a dictionary, with tuples as keys:

dct = {}
dct[(0,0)] = 'X'
if (10,10) in dct:
    dct[(10,10)] += 1
else:
    dct[(10,10] = 0
# Deleting a row / column
dct.pop((10,0))
dct.pop((10,1))
...
dct.pop((10,10))

Dictionaries are very flexible.

Alternatively use a numpy array.

Answer 2

Check this link about Numpy Array. This page has some simple examples of use.

Answer 3

Here is a simple way to handle it:

num_rows, num_cols = 2, 27
table = []

for r in range(num_rows):
    row = []
    table.append(row)
    for c in range(num_cols):
        row.append(c)

print table

Answer 4

No, it makes no particular sense to build a larger array then remove some part of it -- just build what you need. Assuming that by "2d array" you actually mean "list of lists":

def makarray(value, nrows, ncols):
  return [[value]*ncols for _ in range(nrows)]