Python Integer Incrementing with ++

Python integer incrementing with ++

Python doesn't support ++, but you can do:

number += 1

Behaviour of increment and decrement operators in Python

++ is not an operator. It is two + operators. The + operator is the identity operator, which does nothing. (Clarification: the + and - unary operators only work on numbers, but I presume that you wouldn't expect a hypothetical ++ operator to work on strings.)

++count

Parses as

+(+count)

Which translates to

count

You have to use the slightly longer += operator to do what you want to do:

count += 1

I suspect the ++ and -- operators were left out for consistency and simplicity. I don't know the exact argument Guido van Rossum gave for the decision, but I can imagine a few arguments:

• Simpler parsing. Technically, parsing ++count is ambiguous, as it could be +, +, count (two unary + operators) just as easily as it could be ++, count (one unary ++ operator). It's not a significant syntactic ambiguity, but it does exist.
• Simpler language. ++ is nothing more than a synonym for += 1. It was a shorthand invented because C compilers were stupid and didn't know how to optimize a += 1 into the inc instruction most computers have. In this day of optimizing compilers and bytecode interpreted languages, adding operators to a language to allow programmers to optimize their code is usually frowned upon, especially in a language like Python that is designed to be consistent and readable.
• Confusing side-effects. One common newbie error in languages with ++ operators is mixing up the differences (both in precedence and in return value) between the pre- and post-increment/decrement operators, and Python likes to eliminate language "gotcha"-s. The precedence issues of pre-/post-increment in C are pretty hairy, and incredibly easy to mess up.

Incrementing an integer by +1 and adding to string

You stated that you want to add them to a URL so the way to do it would be:

url = "thisisanamazingurl{0:0>4}" # insert your URL instead of thisisanamazingurl

for i in range(10000):
    tempurl = url.format(i)
    print(tempurl)   # instead of print you should do whatever you need to do with it

This works because :0>4 fills the "input string" with leading zeros if it's shorter than 4 characters.

For example with range(10) this prints:

thisisanamazingurl0000
thisisanamazingurl0001
thisisanamazingurl0002
thisisanamazingurl0003
thisisanamazingurl0004
thisisanamazingurl0005
thisisanamazingurl0006
thisisanamazingurl0007
thisisanamazingurl0008
thisisanamazingurl0009

or if you want to store them as a list:

lst = [url.format(i) for i in range(10000)]

increment integer in python

I don't know the specifics of your application, but I would send the data to a list, and then use Python's slice notation to select every 1000th data point.

Try the following snippet.

data = range(100)
every_tenth = data[::10]

Also, you can eliminate the need to explicitly close files if you use the with keyword.

with open(filename) as f:
    data = f.readlines()

The following is your code re-written more 'Pythonically'--that is, it takes advantage of some of the shortcuts that Python offers you over C. You may have to fiddle with it a little to get it to run. I am not sure how you are handling your files.

 def CumulativePerSecond(filename, freq=1000):
    data = []
    with open(filename) as input_file:
        data = input_file.readlines()

    output_file = os.path.splitext(filename)[0] + "_1s.txt"
    with open(out_filename, 'a+') as output:
        for line in data[::freq]:
            output.write(line)

Post increment value while passing to function call

def col(n): 
    sp = [n] 
    if n < 1: 
        return [] 
    while n > 1: 
        if n % 2 == 0: 
            n = n * 2 
        else: 
            n = 3 // n - 1 
        sp.append(n) 
        print(n)
    for i in sp: 
        print(i, end = ' ') 
a = 1 
while True: 
    col(a)
    a+=1

This will work.

Incrementing integer using variable name string

Its never a good idea to eval or exec code, 99 times out of 100 there is a better way to do it. In this case unless you have any other reason that really needs to use eval and exec you could achieve what your trying with a dict. it can hold a key ("name") used to reference or look up your value quite safely.

class MyClass:
    def __init__(self):
        self.my_counts = {
            'rhce': 0,
            'rhcsa': 0
        }
    def add_cert_user(self, userid, args):
        print("start of function", self.my_counts)
        for cert in args:
            if cert  in self.my_counts:
                self.my_counts[cert] += 1
        print("end of function", self.my_counts)

me = MyClass()
args = ['rhce','rhcsa']
me.add_cert_user("test", args)
me.add_cert_user("test", args)
me.add_cert_user("test", args)

OUTPUT

start of function {'rhce': 0, 'rhcsa': 0}
end of function {'rhce': 1, 'rhcsa': 1}
start of function {'rhce': 1, 'rhcsa': 1}
end of function {'rhce': 2, 'rhcsa': 2}
start of function {'rhce': 2, 'rhcsa': 2}
end of function {'rhce': 3, 'rhcsa': 3}

Python - Increment last character in a String by 1

Below is the sample code that would work.

value = 'Run1'
value = value[:-1] + str(int(value[-1])+1)
print(value)
'Run2'

How to check if a list contains integers incrementing by one

In one line:

my_list == list(range(my_list[0], my_list[0] + len(my_list)))

But this probably isn't the most readable.

As a function

def is_incremental(my_l):
   return my_l == list(range(my_l[0], my_l[0] + len(my_l)))

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