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Using string.replace(x, y) to replace all

I have just started to learn python and would like help using string.replace(x,y).
Specifically, replacing all to X's and x's depending whether the letter was originally capitalized or not.
e.g.
John S. Smith -> Xxxx X. Xxxxx
What I have created currently is below.
print("Enter text to translate:", end ="")
sentence = input ()
replaced = sentence.replace("", "x")
print(replaced)
However when I input text like "John Smith". I am returned with "xJxoxhxnx xSx.x xSxmxixtxhx".
Thank you in advance!
Edit: Although string.replace(x,y) may be longer to perform, I'd like to slowly build on my knowledge before finding faster and shorter ways to perform the same operation. I'd highly appreciate it if it was explained in terms of string.replace(x, y) instead of re.sub
Edit2: I have been notified that string.replace is the wrong tool to use. Thank you for your help! I will be reading into re.sub instead.

If you insist on using replace even though it's the wrong tool for the job (because it can only replace one letter at a time and has to go through the whole string every time), here's a way:
>>> s = 'John S. Smith'
>>> for c in s:
if c.islower():
s = s.replace(c, 'x')
if c.isupper():
s = s.replace(c, 'X')
>>> s
'Xxxx X. Xxxxx'
And a somewhat neat more efficient way:
>>> ''.join('x' * c.islower() or 'X' * c.isupper() or c for c in s)
'Xxxx X. Xxxxx'
And a regex way:
>>> re.sub('[A-Z]', 'X', re.sub('[a-z]', 'x', s))
'Xxxx X. Xxxxx'

import re
print("Enter text to translate:", end ="")
sentence = input()
replaced = re.sub("[A-Z]", 'X', re.sub("[a-z]", 'x', sentence))
print replaced
Use re.sub to replace individual character of string or iterate through the string.

Not the correct usecase for string replace.
There are 2 things that you can do:
Loop through the string and perform the operation
Use re.sub to replace using regex. (How to input a regex in string.replace?)

Plain way:
>>> my_string = "John S. Smith"
>>> replaced = ''
>>> for character in my_string:
if character.isupper():
replaced += 'X'
elif character.islower():
replaced += 'x'
else:
replaced += character
>>> replaced
'Xxxx X. Xxxxx'
One liner:
>>> ''.join('x' if c.islower() else 'X' if c.isupper() else c for c in my_string)
'Xxxx X. Xxxxx'

print("Enter text to translate:", end ="")
sentence = input ()
replaced = ''.join(['x' if (i>='a' and i<='z') else 'X' if (i>='A' and i<='Z') else i for i in sentence])
print(replaced)

You can use the re module, and provide re.sub with a callback function to achieve this.
import re
def get_capital(ch):
if ch.isupper():
return "X"
return "x"
def get_capitals(s):
return re.sub("[a-zA-Z]", lambda ch: get_capital(ch.group(0)), s)
print(get_capitals("John S. Smith"))
Has the output:
Xxxx X. Xxxxx
As a matter of style, I've not condensed any of this into lambdas or one-liners, although you probably could.
This will be significantly faster than just repeated concatenation.

** edit fixed code **
Try this instead, it is a bit of a simple and easily breakable example but this is what you would need to achieve what you want:
s = "Testing This"
r = ""
for c in s:
if c.isalpha():
if c.islower():
r += "x"
else:
r += "X"
else:
r += c
print(r)

How to insert a character before first number in a string?

I have a Python 3 program that takes commands such as !down3 or !up48. I wish to insert a character (the letter x) between the numbers and the rest of the command(e.g. !upx48 or !downx3). The letter x must only be inserted at that location.
The commands will only be "up" "down" "left" or "right" and the number will be a maximum of 2 digits (and an integer.)
What is the simplest way of doing this?

You can loop over the command and insert the 'x':
def insert_x(command):
for i, c in enumerate(command):
if c.isdigit():
break
return command[:i] + 'x' + command[i:]
Examples:
>>> insert_x('!down3')
'!downx3'
>>> insert_x('!up48')
'!upx48'

You can use a regex:
>>> li=["!down3", "!up48"]
>>> [re.sub(r'^(\D)(up|down|left|right)(\d+)',r'\1\2x\3', s) for s in li]
['!downx3', '!upx48']
You can also be pickier to only match if it is the entire string and only two digits (as you described):
>>> [re.sub(r'^(\D)(up|down|left|right)(\d{1,2})$',r'\1\2x\3', s) for s in li]

You can try this:
command = "!down3"
indexes = [i for i, a in enumerate(command) if a.isdigit()]
command = list(command)
x = "somevalue"
command.insert(indexes[0], x)
print ''.join(command)

import re
def insertX(s):
split = re.split('(\d.*)',s)
return "x".join(split[:-1])
s = "!down354"
insertX(s)
Results:
!downx354

if you are using this a bunch of times maybe a dict is the answer:
cmds = {d+str(i):d+'x'+str(i) for i in range(10,100) for d in ['up','down','left','right']}
print cmds

Python - making a function that would add "-" between letters

I'm trying to make a function, f(x), that would add a "-" between each letter:
For example:
f("James")
should output as:
J-a-m-e-s-
I would love it if you could use simple python functions as I am new to programming. Thanks in advance. Also, please use the "for" function because it is what I'm trying to learn.
Edit:
yes, I do want the "-" after the "s".

Can I try like this:
>>> def f(n):
... return '-'.join(n)
...
>>> f('james')
'j-a-m-e-s'
>>>
Not really sure if you require the last 'hyphen'.
Edit:
Even if you want suffixed '-', then can do like
def f(n):
return '-'.join(n) + '-'
As being learner, it is important to understand for your that "better to concat more than two strings in python" would be using str.join(iterable), whereas + operator is fine to append one string with another.
Please read following posts to explore further:
Any reason not to use + to concatenate two strings?
which is better to concat string in python?
How slow is Python's string concatenation vs. str.join?

Also, please use the "for" function because it is what I'm trying to learn
>>> def f(s):
m = s[0]
for i in s[1:]:
m += '-' + i
return m
>>> f("James")
'J-a-m-e-s'
m = s[0] character at the index 0 is assigned to the variable m
for i in s[1:]: iterate from the second character and
m += '-' + i append - + char to the variable m
Finally return the value of variable m
If you want - at the last then you could do like this.
>>> def f(s):
m = ""
for i in s:
m += i + '-'
return m
>>> f("James")
'J-a-m-e-s-'

text_list = [c+"-" for c in text]
text_strung = "".join(text_list)

As a function, takes a string as input.
def dashify(input):
output = ""
for ch in input:
output = output + ch + "-"
return output

Given you asked for a solution that uses for and a final -, simply iterate over the message and add the character and '-' to an intermediate list, then join it up. This avoids the use of string concatenations:
>>> def f(message)
l = []
for c in message:
l.append(c)
l.append('-')
return "".join(l)
>>> print(f('James'))
J-a-m-e-s-

I'm sorry, but I just have to take Alexander Ravikovich's answer a step further:
f = lambda text: "".join([c+"-" for c in text])
print(f('James')) # J-a-m-e-s-
It is never too early to learn about list comprehension.
"".join(a_list) is self-explanatory: glueing elements of a list together with a string (empty string in this example).
lambda... well that's just a way to define a function in a line. Think
square = lambda x: x**2
square(2) # returns 4
square(3) # returns 9
Python is fun, it's not {enter-a-boring-programming-language-here}.

python capitalize first letter only

I am aware .capitalize() capitalizes the first letter of a string but what if the first character is a integer?
this
1bob
5sandy
to this
1Bob
5Sandy

Only because no one else has mentioned it:
>>> 'bob'.title()
'Bob'
>>> 'sandy'.title()
'Sandy'
>>> '1bob'.title()
'1Bob'
>>> '1sandy'.title()
'1Sandy'
However, this would also give
>>> '1bob sandy'.title()
'1Bob Sandy'
>>> '1JoeBob'.title()
'1Joebob'
i.e. it doesn't just capitalize the first alphabetic character. But then .capitalize() has the same issue, at least in that 'joe Bob'.capitalize() == 'Joe bob', so meh.

If the first character is an integer, it will not capitalize the first letter.
>>> '2s'.capitalize()
'2s'
If you want the functionality, strip off the digits, you can use '2'.isdigit() to check for each character.
>>> s = '123sa'
>>> for i, c in enumerate(s):
... if not c.isdigit():
... break
...
>>> s[:i] + s[i:].capitalize()
'123Sa'

This is similar to #Anon's answer in that it keeps the rest of the string's case intact, without the need for the re module.
def sliceindex(x):
i = 0
for c in x:
if c.isalpha():
i = i + 1
return i
i = i + 1
def upperfirst(x):
i = sliceindex(x)
return x[:i].upper() + x[i:]
x = '0thisIsCamelCase'
y = upperfirst(x)
print(y)
# 0ThisIsCamelCase
As #Xan pointed out, the function could use more error checking (such as checking that x is a sequence - however I'm omitting edge cases to illustrate the technique)
Updated per #normanius comment (thanks!)
Thanks to #GeoStoneMarten in pointing out I didn't answer the question! -fixed that

Here is a one-liner that will uppercase the first letter and leave the case of all subsequent letters:
import re
key = 'wordsWithOtherUppercaseLetters'
key = re.sub('([a-zA-Z])', lambda x: x.groups()[0].upper(), key, 1)
print key
This will result in WordsWithOtherUppercaseLetters

As seeing here answered by Chen Houwu, it's possible to use string package:
import string
string.capwords("they're bill's friends from the UK")
>>>"They're Bill's Friends From The Uk"

a one-liner: ' '.join(sub[:1].upper() + sub[1:] for sub in text.split(' '))

You can replace the first letter (preceded by a digit) of each word using regex:
re.sub(r'(\d\w)', lambda w: w.group().upper(), '1bob 5sandy')
output:
1Bob 5Sandy

def solve(s):
for i in s[:].split():
s = s.replace(i, i.capitalize())
return s
This is the actual code for work. .title() will not work at '12name' case

I came up with this:
import re
regex = re.compile("[A-Za-z]") # find a alpha
str = "1st str"
s = regex.search(str).group() # find the first alpha
str = str.replace(s, s.upper(), 1) # replace only 1 instance
print str

def solve(s):
names = list(s.split(" "))
return " ".join([i.capitalize() for i in names])
Takes a input like your name: john doe
Returns the first letter capitalized.(if first character is a number, then no capitalization occurs)
works for any name length

python string manipulation [duplicate]

I have a string s with nested brackets: s = "AX(p>q)&E((-p)Ur)"
I want to remove all characters between all pairs of brackets and store in a new string like this: new_string = AX&E
i tried doing this:
p = re.compile("\(.*?\)", re.DOTALL)
new_string = p.sub("", s)
It gives output: AX&EUr)
Is there any way to correct this, rather than iterating each element in the string?

Another simple option is removing the innermost parentheses at every stage, until there are no more parentheses:
p = re.compile("\([^()]*\)")
count = 1
while count:
s, count = p.subn("", s)
Working example: http://ideone.com/WicDK

You can just use string manipulation without regular expression
>>> s = "AX(p>q)&E(qUr)"
>>> [ i.split("(")[0] for i in s.split(")") ]
['AX', '&E', '']
I leave it to you to join the strings up.

>>> import re
>>> s = "AX(p>q)&E(qUr)"
>>> re.compile("""\([^\)]*\)""").sub('', s)
'AX&E'

Yeah, it should be:
>>> import re
>>> s = "AX(p>q)&E(qUr)"
>>> p = re.compile("\(.*?\)", re.DOTALL)
>>> new_string = p.sub("", s)
>>> new_string
'AX&E'

Nested brackets (or tags, ...) are something that are not possible to handle in a general way using regex. See http://www.amazon.de/Mastering-Regular-Expressions-Jeffrey-Friedl/dp/0596528124/ref=sr_1_1?ie=UTF8&s=gateway&qid=1304230523&sr=8-1-spell for details why. You would need a real parser.
It's possible to construct a regex which can handle two levels of nesting, but they are already ugly, three levels will already be quite long. And you don't want to think about four levels. ;-)

You can use PyParsing to parse the string:
from pyparsing import nestedExpr
import sys
s = "AX(p>q)&E((-p)Ur)"
expr = nestedExpr('(', ')')
result = expr.parseString('(' + s + ')').asList()[0]
s = ''.join(filter(lambda x: isinstance(x, str), result))
print(s)
Most code is from: How can a recursive regexp be implemented in python?

You could use re.subn():
import re
s = 'AX(p>q)&E((-p)Ur)'
while True:
s, n = re.subn(r'\([^)(]*\)', '', s)
if n == 0:
break
print(s)
Output
AX&E

this is just how you do it:
# strings
# double and single quotes use in Python
"hey there! welcome to CIP"
'hey there! welcome to CIP'
"you'll understand python"
'i said, "python is awesome!"'
'i can\'t live without python'
# use of 'r' before string
print(r"\new code", "\n")
first = "code in"
last = "python"
first + last #concatenation
# slicing of strings
user = "code in python!"
print(user)
print(user[5]) # print an element
print(user[-3]) # print an element from rear end
print(user[2:6]) # slicing the string
print(user[:6])
print(user[2:])
print(len(user)) # length of the string
print(user.upper()) # convert to uppercase
print(user.lstrip())
print(user.rstrip())
print(max(user)) # max alphabet from user string
print(min(user)) # min alphabet from user string
print(user.join([1,2,3,4]))
input()