DNASeq = "ATGTCTCATTCAAAGCA" 
#DNASeq = raw_input("Enter a sequence: ")
DNASeq = DNASeq.upper()  # convert to uppercase for .count() function
DNASeq = DNASeq.replace(" ","") # remove spaces

print 'Sequence:', DNASeq 
 
# below are nested functions: first find the length, then make it float
 
SeqLength = float(len(DNASeq)) 
 
print "Sequence Length:", SeqLength
 
NumberA = DNASeq.count('A')
NumberC = DNASeq.count('C')
NumberG = DNASeq.count('G')
NumberT = DNASeq.count('T')
 
# Old way to output the Numbers
# print "A:", NumberA/SeqLength
# print "C:", NumberC/SeqLength
# print "G:", NumberG/SeqLength
# print "T:", NumberT/SeqLength
 
# Calculate percentage and output to 1 decimal
print "A: %.1f" % (100 * NumberA / SeqLength)
print "C: %.1f" % (100 * NumberC / SeqLength)
print "G: %.1f" % (100 * NumberG / SeqLength)
print "T: %.1f" % (100 * NumberT / SeqLength)
 
#
# End of Chapter 8
 
# Beginning of Chapter 9
#
# Calculating primer melting points with different formulas by length
 
TotalStrong = NumberG + NumberC
TotalWeak = NumberA + NumberT
 
if SeqLength >=  14:
  #formula for sequences > 14 nucleotides long 
	MeltTempLong = 64.9 + 41 * (TotalStrong - 16.4) / SeqLength 
	print "Tm Long (>14): %.1f C" % (MeltTempLong)
else:
	#formula for sequences less than 14 nucleotides long
	MeltTemp = (4 * TotalStrong) + (2 * TotalWeak)
	print "Tm Short: %.1f C" % (MeltTemp)
 

%whos