import sys
from Bio import SeqIO

# Parse the command line.
if (len(sys.argv) != 2):
  print "USAGE: read-fasta.py <file>"
  sys.exit(1)
fastaFilename = sys.argv[1]

# Initialize counters.
minLength = 999999999
maxLength = 0
sumLength = 0
numSeqs = 0

# Read the file and increment values.
fastaFile = open(fastaFilename, "r")
for seq in SeqIO.parse(fastaFile, "fasta"):
  length = len(seq)
  if (length < minLength):
    minLength = length
  if (length > maxLength):
    maxLength = length
  sumLength += length
  numSeqs += 1

fastaFile.close()

# Print
print "Number of sequences = %d" % numSeqs
print "Number of residues = %d" % sumLength
print "Average length = %g" % (float(sumLength) / float(numSeqs))
print "Minimum length = %d" % minLength
print "Maximum length = %d" % maxLength