returning specifics from a file, python

Question

I have this code, where I am trying to count the number of:

• Lines of code in a .py script
• for_loops ("for ") -while_loops ("while ")
• if_statements ("if ")
• function definitions ("def ")
• multiplication signs ("*"
• division signs ("/"
• addition signs ("+")
• subtraction signs ("-")

On the mathematical signs the code works, but when the code is looking for if statements it returns 2, when there is one, which is the main problem, but it makes me think I have written the for loop incorrectly, which could bring up more problems later. As well as this I am not sure how to print the Author line which comes up as [] instead of the name of the Author

The code:

from collections import Counter
FOR_=0
WHILE_=0
IF_=0
DEF_=0
x =input("Enter file or directory: ")
print ("Enter file or directory: {0}".format(x))
print ("Filename {0:>20}".format(x))
b= open(x)
c=b.readlines()
d=b.readlines(2)
print ("Author {0:<18}".format(d))
print ("lines_of_code {0:>8}".format((len (c))))
counter = Counter(str(c))
for line in c:
    if  ("for ") in line:
        FOR_+=1
        print ("for_loops {0:>12}".format((FOR_)))
for line in c:
    if  ("while ") in line:
        WHILE_+=1
        print ("while_loops {0:>10}".format((WHILE_)))
for line in c:
    if  ("if ") in line:
        IF_+=1
        a=IF_
        print ("if_statements {0:>8}".format((a)))
for line in c:
    if  ("def ") in line:
        DEF_+=1
        print ("function_definitions {0}".format((DEF_)))
print ("multiplications {0:>6}".format((counter['*'])))
print ("divisions {0:>12}".format((counter['/'])))
print ("additions {0:>12}".format((counter['+'])))
print ("subtractions {0:>9}".format((counter['-'])))

The file being read from:

'''Dumbo
Author: Hector McTavish'''
    for for for  # Should count as 1 for statement
while_im_alive # Shouldn't count as a while
while blah # But this one should
  if defined # Should be an if but not a def
  def if # Should be a def but not an if
    x = (2 * 3) + 4 * 2 * 7 / 1 - 2  # Various operators

Any help would be much appreciated

Answer 1

Instead of treating the source code as a string, use the ast module to parse it and then just walk through the nodes:

import ast
from collections import Counter

tree = ast.parse('''
"""
Author: Nobody
"""

def foo(*args, **kwargs):
    for i in range(10):
        if i != 2**2:
            print(i * 2 * 3 * 2)

def bar():
    pass
''')

counts = Counter(node.__class__ for node in ast.walk(tree))

print('The docstring says:', repr(ast.get_docstring(tree)))
print('You have', counts[ast.Mult], 'multiplication signs.')
print('You have', counts[ast.FunctionDef], 'function definitions.')
print('You have', counts[ast.If], 'if statements.')

It's pretty straightforward and handles all of your corner cases:

The docstring says: 'Author: Nobody'
You have 3 multiplication signs.
You have 2 function definitions.
You have 1 if statements.

Answer 2

if ("if ") in line will also count def if #.