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How about this:

signs = ['=','=','>=','>=','>=','<=','<=','<=','<=','<=']
# lines: will be the rows of the matrix
lines = []
# column: where to put the next nonzero entry
column = 0
# total number of columns in matrix
size = sum(len(s) for s in signs)
for s in signs:
    if s == '=':
        new = column * [0] + [1] + (size - column - 1) * [0]
        column += 1
    elif s == '>=':
        new = column * [0] + [-1, 1] + (size - column - 2) * [0]
        column += 2
    elif s == '<=':
        new = column * [0] + [1, 1] + (size - column - 2) * [0]
        column += 2
    lines.append(new)
mat = matrix(lines)