Develop Reference

How can I write two letters with many spaces between them in Python?

I'm trying to make a pattern looking like this:
click here, it's a capital A made out of A's
I'm running into trouble getting the A's to space apart by four or five spaces (A____A). I have to use the format method, but I have no idea how to go about doing that. What is the easiest way? I tried to do something like this, but it says invalid syntax and I am very confused about how to do it right.
print('A',{:4d}.format('A'))

You need to wrap the format in a string, as in '{:4d}'.format(42).
Note that the d specifier expects an integer to be formatted, so '{:4d}'.format('A') would raise an error since 'A' is a string, not an int.
Instead, you remove the d:
print('A{:>4}'.format('A')) # or print(f'A{"A":>4}')
# A A
The > will right-align the 'A', so that the spaces go in the middle.
A simpler way, without bothering with the formatting mini-language, is to simply insert the spaces:
print('A' + ' '*3 + 'A')

You can try
print(f"{A:04}")

Escape double quotes when converting a dict to json in Python

I need to escape double quotes when converting a dict to json in Python, but I'm struggling to figure out how.
So if I have a dict like {'foo': 'bar'}, I'd like to convert it to json and escape the double quotes - so it looks something like:
'{\"foo\":\"bar\"}'
json.dumps doesn't do this, and I have tried something like:
json.dumps({'foo': 'bar'}).replace('"', '\\"') which ends up formatting like so:
'{\\"foo\\": \\"bar\\"}'
This seems like such a simple problem to solve but I'm really struggling with it.

Your last attempt json.dumps({'foo': 'bar'}).replace('"', '\\"') is actually correct for what you think you want.
The reason you see this:
'{\\"foo\\": \\"bar\\"}'
Is because you're printing the representation of the string. The string itself will have only a single backslash for each quote. If you use print() on that result, you will see a single backslash

What you have does work. Python is showing you the literal representation of it. If you save it to a variable and print it shows you what you're looking for.
>>> a = json.dumps({'foo': 'bar'}).replace('"', '\\"')
>>> print a
{\"foo\": \"bar\"}
>>> a
'{\\"foo\\": \\"bar\\"}'

Python: replace &quote; to \"

I have a string like
This was really &quote;awesome&quote; isn't it?
And i need to convert the text to this format
This was really \"awesome\" isn't it?
I tried to use replace("&quote;", "\"") but I got this one:
This was really "awesome" isn\'t it?
Which is not exactly what I am trying to get.
Any idea?

Try using replace("&quote;", r'\"'). The r'...' with the "r" in front of the quotes means make it a "raw" string, so the backslashes are not interpreted as special characters (which is what happened to you in the first case).

String Delimiter in Python

I want to do split a string using "},{" as the delimiter. I have tried various things but none of them work.
string="2,1,6,4,5,1},{8,1,4,9,6,6,7,0},{6,1,2,3,9},{2,3,5,4,3 "
Split it into something like this:
2,1,6,4,5,1
8,1,4,9,6,6,7,0
6,1,2,3,9
2,3,5,4,3
string.split("},{") works at the Python console but if I write a Python script in which do this operation it does not work.

You need to assign the result of string.split("},{") to a new string. For example:
string2 = string.split("},{")
I think that is the reason you think it works at the console but not in scripts. In the console it just prints out the return value, but in the script you want to make sure you use the returned value.

You need to return the string back to the caller. Assigning to the string parameter doesn't change the caller's variable, so those changes are lost.
def convert2list(string):
string = string.strip()
string = string[2:len(string)-2].split("},{")
# Return to caller.
return string
# Grab return value.
converted = convert2list("{1,2},{3,4}")

You could do it in steps:
Split at commas to get "{...}" strings.
Remove leading and trailing curly braces.
It might not be the most Pythonic or efficient, but it's general and doable.

I was taking the input from the console in the form of arguments to the script....
So when I was taking the input as {{2,4,5},{1,9,4,8,6,6,7},{1,2,3},{2,3}} it was not coming properly in the arg[1] .. so the split was basically splitting on an empty string ...

If I run the below code from a script file (in Python 2.7):
string="2,1,6,4,5,1},{8,1,4,9,6,6,7,0},{6,1,2,3,9},{2,3,5,4,3 "
print string.split("},{")
Then the output I got is:
['2,1,6,4,5,1', '8,1,4,9,6,6,7,0', '6,1,2,3,9', '2,3,5,4,3 ']
And the below code also works fine:
string="2,1,6,4,5,1},{8,1,4,9,6,6,7,0},{6,1,2,3,9},{2,3,5,4,3 "
def convert2list(string):
string=string.strip()
string=string[:len(string)].split("},{")
print string
convert2list(string)

Use This:
This will split the string considering },{ as a delimiter and print the list with line breaks.
string = "2,1,6,4,5,1},{8,1,4,9,6,6,7,0},{6,1,2,3,9},{2,3,5,4,3"
for each in string.split('},{'):
print each
Output:
2,1,6,4,5,1
8,1,4,9,6,6,7,0
6,1,2,3,9
2,3,5,4,3
If you want to print the split items in the list only you can use this simple print option.
string = "2,1,6,4,5,1},{8,1,4,9,6,6,7,0},{6,1,2,3,9},{2,3,5,4,3"
print string.split('},{')
Output:
['2,1,6,4,5,1', '8,1,4,9,6,6,7,0', '6,1,2,3,9', '2,3,5,4,3']

Quite simply ,you have to use split() method ,and "},{" as a delimeter, then print according to arguments (because string will be a list ) ,
like the following :
string.split("},{")
for i in range(0,len(string)):
print(string[i])

How can I replace double and single quotations in a string efficiently?

I'm parsing a xml file and inserting it into database.
However since some text containes double or single quotation I'm having problem with insertion. Currently I'm using the code shown below. But it seems it's inefficient.
s = s.replace('"', ' ')
s = s.replace("'", ' ')
Is there any way I can insert text without replacing these quotations?
OR
Is there any efficient way to substitute them efficiently ?
Thanks !

Why can't you insert strings containing quote marks into your database? Is there some weird data type that permits any character except a quote mark? Or are you building an insert statement with literal strings, rather than binding your strings to query parameters as you should be doing?
If you're doing
cursor.execute('insert into mytable (somefield) values ("%s")' % (mystring))
then that's unsafe and wrong. Instead, you should be doing
cursor.execute('insert into mytable (somefield) values (%(myparam)s)',
dict(myparam=mystring))

you should use str.translate instead of doing two replace() calls
>>> import string
>>> quotes_to_spaces=string.maketrans('"\''," ")
>>> s=s.translate(quotes_to_spaces)

You could try something like _mysql.escape_string():
>>> import _mysql
>>> a = '''I said, "Don't do that"'''
>>> a
'I said, "Don\'t do that"'
>>> _mysql.escape_string(a)
'I said, \\"Don\\\'t do that\\"'
However, the manual recommends using connection.escape_string(), but I think you need a database connection first.