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Changing the first letter of a string into upper case in python

I aim to convert a proper noun for instance to have an upper case first letter after an input of the name has been made.

Using string.title() you achieve that:
>>> name = 'joe'
>>> name.title()
'Joe'

Use upper() method, like this:
mystr = "hello world"
mystr = mystr[0].upper() + mystr[1:]

.capitalize() and .title(), can be used, but both have issues:
>>> "onE".capitalize()
'One'
>>> "onE".title()
'One'
Both changes other letters of the string to smallcase.
Write your own:
>>> xzy = lambda x: x[0].upper() + x[1:]
>>> xzy('onE')
'OnE'

You can use https://pydash.readthedocs.io/en/latest/api.html#pydash.strings.capitalize.
Install pydash - pip install pydash
example:
from pydash import py_
greetings = "hello Abdullah"
py_.capitalize(greetings) # returns 'Hello abdullah'
py_.capitalize(greetings, strict = False) # returns 'Hello Abdullah'

use .format() in a string in two steps

I have a string in which I want to replace some variables, but in different steps, something like:
my_string = 'text_with_{var_1}_to_variables_{var_2}'
my_string.format(var_1='10')
### make process 1
my_string.format(var_2='22')
But when I try to replace the first variable I get an Error:
KeyError: 'var_2'
How can I accomplish this?
Edit:
I want to create a new list:
name = 'Luis'
ids = ['12344','553454','dadada']
def create_list(name,ids):
my_string = 'text_with_{var_1}_to_variables_{var_2}'.replace('{var_1}',name)
return [my_string.replace('{var_2}',_id) for _id in ids ]
this is the desired output:
['text_with_Luis_to_variables_12344',
'text_with_Luis_to_variables_553454',
'text_with_Luis_to_variables_dadada']
But using .format instead of .replace.

In simple words, you can not replace few arguments with format {var_1}, var_2 in string(not all) using format. Even though I am not sure why you want to only replace partial string, but there are few approaches that you may follow as a workaround:
Approach 1: Replacing the variable you want to replace at second step by {{}} instead of {}. For example: Replace {var_2} by {{var_2}}
>>> my_string = 'text_with_{var_1}_to_variables_{{var_2}}'
>>> my_string = my_string.format(var_1='VAR_1')
>>> my_string
'text_with_VAR_1_to_variables_{var_2}'
>>> my_string = my_string.format(var_2='VAR_2')
>>> my_string
'text_with_VAR_1_to_variables_VAR_2'
Approach 2: Replace once using format and another using %.
>>> my_string = 'text_with_{var_1}_to_variables_%(var_2)s'
# Replace first variable
>>> my_string = my_string.format(var_1='VAR_1')
>>> my_string
'text_with_VAR_1_to_variables_%(var_2)s'
# Replace second variable
>>> my_string = my_string % {'var_2': 'VAR_2'}
>>> my_string
'text_with_VAR_1_to_variables_VAR_2'
Approach 3: Adding the args to a dict and unpack it once required.
>>> my_string = 'text_with_{var_1}_to_variables_{var_2}'
>>> my_args = {}
# Assign value of `var_1`
>>> my_args['var_1'] = 'VAR_1'
# Assign value of `var_2`
>>> my_args['var_2'] = 'VAR_2'
>>> my_string.format(**my_args)
'text_with_VAR_1_to_variables_VAR_2'
Use the one which satisfies your requirement. :)

Do you have to use format? If not, can you just use string.replace? like
my_string = 'text_with_#var_1#_to_variables_#var2#'
my_string = my_string.replace("#var_1#", '10')
###
my_string = my_string.replace("#var2#", '22')

following seems to work now.
s = 'a {} {{}}'.format('b')
print(s) # prints a b {}
print(s.format('c')) # prints a b c

Checking two string in python?

let two strings
s='chayote'
d='aceihkjouty'
the characters in string s is present in d Is there any built-in python function to accomplish this ?
Thanks In advance

Using sets:
>>> set("chayote").issubset("aceihkjouty")
True
Or, equivalently:
>>> set("chayote") <= set("aceihkjouty")
True

I believe you are looking for all and a generator expression:
>>> s='chayote'
>>> d='aceihkjouty'
>>> all(x in d for x in s)
True
>>>
The code will return True if all characters in string s can be found in string d.
Also, if string s contains duplicate characters, it would be more efficient to make it a set using set:
>>> s='chayote'
>>> d='aceihkjouty'
>>> all(x in d for x in set(s))
True
>>>

Try this
for i in s:
if i in d:
print i

python convert unicode to string

I got my results from sqlite by python, it's like this kind of tuples: (u'PR:000017512',)
However, I wanna print it as 'PR:000017512'. At first, I tried to select the first one in tuple by using index [0]. But the print out results is still u'PR:000017512'. Then I used str() to convert and nothing changed. How can I print this without u''?

You're confusing the string representation with its value. When you print a unicode string the u doesn't get printed:
>>> foo=u'abc'
>>> foo
u'abc'
>>> print foo
abc
Update:
Since you're dealing with a tuple, you don't get off this easy: You have to print the members of the tuple:
>>> foo=(u'abc',)
>>> print foo
(u'abc',)
>>> # If the tuple really only has one member, you can just subscript it:
>>> print foo[0]
abc
>>> # Join is a more realistic approach when dealing with iterables:
>>> print '\n'.join(foo)
abc

Don't see the problem:
>>> x = (u'PR:000017512',)
>>> print x
(u'PR:000017512',)
>>> print x[0]
PR:000017512
>>>
You the string is in unicode format, but it still means PR:000017512
Check out the docs on String literals
http://docs.python.org/2/reference/lexical_analysis.html#string-literals

In [22]: unicode('foo').encode('ascii','replace')
Out[22]: 'foo'

Put a letter to the front of a string in python

is there a quick way to place a string in the front of another string in python? if so how?
as an example let's say that string = 'pple'. How would I put the string_2 = 'a' at the start of string?

concatenate it:
string=char+string

>>> strg = 'pple'
>>> char = 'a'
>>> char + strg
'apple'
>>> strg = char + strg
>>> strg
'apple'
>>>

Here's a quick example:
string='a'+string

Lots of correct answers. You could also use "string interpolation" (or just "string formatting", when referring to str.format) if you are really looking to do some string manipulating (I only mention it because figuring out what the % is called can be frustrating):
>>> one_string = 'One string'
>>> two_string = 'two string'
>>> one_two = '%s, %s, red string, blue string' % (one_string, two_string)
>>> one_two
'One string, two string, red string, blue string'
I'll leave you to check it out if you like. See, for example, http://docs.python.org/library/stdtypes.html#string-formatting-operations