How to stop the input function from inserting a new line?

I know I can stop print from writing a newline by adding a comma

print "Hello, world!",
# print("Hello, world!", end='') for Python 3.x

But how do I stop raw_input (or input for Python 3.x) from writing a newline?

print "Hello, ",
name = raw_input()
print开发者_开发知识库 ", how do you do?"

Result:

Hello, Tomas
, how do you do?

Result I want:

Hello, Tomas, how do you do?

But how do I stop raw_input from writing a newline?

In short: You can't.

raw_input() will always echo the text entered by the user, including the trailing newline. That means whatever the user is typing will be printed to standard output.

If you want to prevent this, you will have to use a terminal control library such as the curses module. This is not portable, though -- for example, curses in not available on Windows systems.

I see that nobody has given a working solution, so I decided I might give it a go. As Ferdinand Beyer said, it is impossible to get raw_input() to not print a new line after the user input. However, it is possible to get back to the line you were before. I made it into an one-liner. You may use:

print '\033[{}C\033[1A'.format(len(x) + y),

where x is an integer of the length of the given user input and y an integer of the length of raw_input()'s string. Though it might not work on all terminals (as I read when I learned about this method), it works fine on mine. I'm using Kubuntu 14.04.
The string '\033[4C' is used to jump 4 indexes to the right, so it would be equivalent to ' ' * 4. In the same way, the string '\033[1A' is used to jump 1 line up. By using the letters A, B, C or D on the last index of the string, you can go up, down, right and left respectively.

Note that going a line up will delete the existing printed character on that spot, if there is one.

This circumvents it, somewhat, but doesn't assign anything to variable name:

print("Hello, {0}, how do you do?".format(raw_input("Enter name here: ")))

It will prompt the user for a name before printing the entire message though.

You can use getpass instead of raw_input if you don't want it to make a new line!

import sys, getpass

def raw_input2(value="",end=""):
    sys.stdout.write(value)
    data = getpass.getpass("")
    sys.stdout.write(data)
    sys.stdout.write(end)
    return data

An alternative to backtracking the newline is defining your own function that emulates the built-in input function, echoing and appending every keystroke to a response variable except Enter (which will return the response), whilst also handling Backspace, Del, Home, End, arrow keys, line history, KeyboardInterrupt, EOFError, SIGTSTP and pasting from the clipboard. It's very simple.

Note that on Windows, you'll need to install pyreadline if you want to use line history with the arrow keys like in the usual input function, although it's incomplete so the functionality is still not quite right. In addition, if you're not on v1511 or greater of Windows 10, you'll need to install the colorama module (if you're on Linux or macOS, nothing needs to be done).

Also, due to msvcrt.getwch using '\xe0' to indicate special characters, you won't be able to type 'à'. You should be able to paste it though.

Below is code that makes this work on updated Windows 10 systems (at least v1511), Debian-based Linux distros and maybe macOS and other *NIX operating systems. It should also work regardless of whether you have pyreadline installed on Windows, though it'll lack some functionality.

In windows_specific.py:

"""Windows-specific functions and variables for input_no_newline."""
import ctypes
from msvcrt import getwch  # pylint: disable=import-error, unused-import
from shared_stuff import ANSI

try:
    import colorama  # pylint: disable=import-error
except ImportError:
    kernel32 = ctypes.windll.kernel32
    # Enable ANSI support to move the text cursor
    kernel32.SetConsoleMode(kernel32.GetStdHandle(-11), 7)
else:
    colorama.init()


def get_clipboard_data():
    """Return string previously copied from Windows clipboard.

    Adapted from <http://stackoverflow.com/a/23285159/6379747>.

    """
    CF_TEXT = 1
    user32 = ctypes.windll.user32
    user32.OpenClipboard(0)
    try:
        if user32.IsClipboardFormatAvailable(CF_TEXT):
            data = user32.GetClipboardData(CF_TEXT)
            data_locked = kernel32.GlobalLock(data)
            text = ctypes.c_char_p(data_locked)
            kernel32.GlobalUnlock(data_locked)
    finally:
        user32.CloseClipboard()
    return text.value


def sigtstp():
    """Raise EOFError from Ctrl-Z since SIGTSTP doesn't exist on Windows."""
    raise EOFError


input_code = {
    **ANSI,
    'CSI': [['\xe0', '\x00'], ''],
    'up': 'H',
    'down': 'P',
    'right': 'M',
    'left': 'K',
    'end': 'O',
    'home': 'G',
    'backspace': '\b',
    'del': 'S',
}

In unix_specific.py:

"""Functions and variables for Debian-based Linux distros and macOS."""
import sys
import os
import tty
import signal
import termios
from shared_stuff import ANSI

def getwch():
    """Return a single character from user input without echoing.

    ActiveState code, adapted from
    <http://code.activestate.com/recipes/134892> by Danny Yoo under
    the Python Software Foundation license.

    """
    file_descriptor = sys.stdin.fileno()
    old_settings = termios.tcgetattr(file_descriptor)
    try:
        tty.setraw(file_descriptor)
        char = sys.stdin.read(1)
    finally:
        termios.tcsetattr(file_descriptor, termios.TCSADRAIN, old_settings)
    return char


def get_clipboard_data():
    """Return nothing; *NIX systems automagically change sys.stdin."""
    return ''


def sigtstp():
    """Suspend the script."""
    os.kill(os.getpid(), signal.SIGTSTP)


input_code = {
    **ANSI,
    'CSI': ['\x1b', '['],
    'backspace': '\x7f',
    'del': ['3', '~'],
}

In readline_available.py:

"""Provide functions for up and down arrows if readline is installed.

Basically to prevent duplicate code and make it work on systems without
readline.

"""
try:
    import readline
except ImportError:
    import pyreadline as readline
from shared_stuff import move_cursor


def init_history_index():
    """Return index for last element of readline.get_history_item."""
    # readline.get_history_item is one-based
    return readline.get_current_history_length() + 1


def restore_history(history_index, replaced, cursor_position):
    """Replace 'replaced' with history and return the replacement."""
    try:
        replacement = readline.get_history_item(history_index)
    except IndexError:
        replacement = None
    if replacement is not None:
        move_cursor('right', len(replaced) - cursor_position)
        print('\b \b' * len(replaced), end='', flush=True)
        print(replacement, end='', flush=True)
        return replacement
    return replaced


def store_and_replace_history(history_index, replacement, old_history):
    """Store history and then replace it."""
    old_history[history_index] = readline.get_history_item(history_index)
    try:
        readline.replace_history_item(history_index - 1, replacement)
    except AttributeError:
    # pyreadline is incomplete
        pass


def handle_prev_history(history_index, replaced, old_history,
                        input_replaced, history_modified):
    """Handle some up-arrow logic."""
    try:
        history = readline.get_history_item(history_index - 1)
    except IndexError:
        history = None
    if history is not None:
        if history_index > readline.get_current_history_length():
            readline.add_history(replaced)
            input_replaced = True
        else:
            store_and_replace_history(
                history_index, replaced, old_history)
            history_modified = True
        history_index -= 1
    return (history_index, input_replaced, history_modified)


def handle_next_history(history_index, replaced, old_history,
                        input_replaced, history_modified):
    """Handle some down-arrow logic."""
    try:
        history = readline.get_history_item(history_index + 1)
    except IndexError:
        history = None
    if history is not None:
        store_and_replace_history(history_index, replaced, old_history)
        history_modified = True
        history_index += 1
        input_replaced = (not history_index
                            == readline.get_current_history_length())
    return (history_index, input_replaced, history_modified)


def finalise_history(history_index, response, old_history,
                     input_replaced, history_modified):
    """Change history before the response will be returned elsewhere."""
    try:
        if input_replaced:
            readline.remove_history_item(history_index - 1)
        elif history_modified:
            readline.remove_history_item(history_index - 1)
            readline.add_history(old_history[history_index - 1])
    except AttributeError:
    # pyreadline is also missing remove_history_item
        pass
    readline.add_history(response)

In readline_unavailable.py:

"""Provide dummy functions for if readline isn't available."""
# pylint: disable-msg=unused-argument


def init_history_index():
    """Return an index of 1 which probably won't ever change."""
    return 1


def restore_history(history_index, replaced, cursor_position):
    """Return the replaced thing without replacing it."""
    return replaced


def store_and_replace_history(history_index, replacement, old_history):
    """Don't store history."""
    pass


def handle_prev_history(history_index, replaced, old_history,
                        input_replaced, history_modified):
    """Return 'input_replaced' and 'history_modified' without change."""
    return (history_index, input_replaced, history_modified)


def handle_next_history(history_index, replaced, old_history,
                        input_replaced, history_modified):
    """Also return 'input_replaced' and 'history_modified'."""
    return (history_index, input_replaced, history_modified)


def finalise_history(history_index, response, old_history,
                     input_replaced, history_modified):
    """Don't change nonexistent history."""
    pass

In shared_stuff.py:

"""Provide platform-independent functions and variables."""
ANSI = {
    'CSI': '\x1b[',
    'up': 'A',
    'down': 'B',
    'right': 'C',
    'left': 'D',
    'end': 'F',
    'home': 'H',
    'enter': '\r',
    '^C': '\x03',
    '^D': '\x04',
    '^V': '\x16',
    '^Z': '\x1a',
}


def move_cursor(direction, count=1):
    """Move the text cursor 'count' times in the specified direction."""
    if direction not in ['up', 'down', 'right', 'left']:
        raise ValueError("direction should be either 'up', 'down', 'right' "
                         "or 'left'")
    # A 'count' of zero still moves the cursor, so this needs to be
    # tested for.
    if count != 0:
        print(ANSI['CSI'] + str(count) + ANSI[direction], end='', flush=True)


def line_insert(text, extra=''):
    """Insert text between terminal line and reposition cursor."""
    if not extra:
    # It's not guaranteed that the new line will completely overshadow
    # the old one if there is no extra. Maybe something was 'deleted'?
        move_cursor('right', len(text) + 1)
        print('\b \b' * (len(text)+1), end='', flush=True)
    print(extra + text, end='', flush=True)
    move_cursor('left', len(text))

And finally, in input_no_newline.py:

#!/usr/bin/python3
"""Provide an input function that doesn't echo a newline."""
try:
from windows_specific import getwch, get_clipboard_data, sigtstp, input_code
except ImportError:
    from unix_specific import getwch, get_clipboard_data, sigtstp, input_code
try:
    from readline_available import (init_history_index, restore_history,
                                    store_and_replace_history,
                                    handle_prev_history, handle_next_history,
                                    finalise_history)
except ImportError:
    from readline_unavailable import (init_history_index, restore_history,
                                      store_and_replace_history,
                                      handle_prev_history, handle_next_history,
                                      finalise_history)
from shared_stuff import ANSI, move_cursor, line_insert


def input_no_newline(prompt=''):  # pylint: disable=too-many-branches, too-many-statements
    """Echo and return user input, except for the newline."""
    print(prompt, end='', flush=True)
    response = ''
    position = 0
    history_index = init_history_index()
    input_replaced = False
    history_modified = False
    replacements = {}

    while True:
        char = getwch()
        if char in input_code['CSI'][0]:
            char = getwch()
            # Relevant input codes are made of two to four characters
            if char == input_code['CSI'][1]:
                # *NIX uses at least three characters, only the third is
                # important
                char = getwch()
            if char == input_code['up']:
                (history_index, input_replaced, history_modified) = (
                    handle_prev_history(
                        history_index, response, replacements, input_replaced,
                        history_modified))
                response = restore_history(history_index, response, position)
                position = len(response)
            elif char == input_code['down']:
                (history_index, input_replaced, history_modified) = (
                    handle_next_history(
                        history_index, response, replacements, input_replaced,
                        history_modified))
                response = restore_history(history_index, response, position)
                position = len(response)
            elif char == input_code['right'] and position < len(response):
                move_cursor('right')
                position += 1
            elif char == input_code['left'] and position > 0:
                move_cursor('left')
                position -= 1
            elif char == input_code['end']:
                move_cursor('right', len(response) - position)
                position = len(response)
            elif char == input_code['home']:
                move_cursor('left', position)
                position = 0
            elif char == input_code['del'][0]:
                if ''.join(input_code['del']) == '3~':
                    # *NIX uses '\x1b[3~' as its del key code, but only
                    # '\x1b[3' has currently been read from sys.stdin
                    getwch()
                backlog = response[position+1 :]
                response = response[:position] + backlog
                line_insert(backlog)
        elif char == input_code['backspace']:
            if position > 0:
                backlog = response[position:]
                response = response[: position-1] + backlog
                print('\b', end='', flush=True)
                position -= 1
                line_insert(backlog)
        elif char == input_code['^C']:
            raise KeyboardInterrupt
        elif char == input_code['^D']:
            raise EOFError
        elif char == input_code['^V']:
            paste = get_clipboard_data()
            backlog = response[position:]
            response = response[:position] + paste + backlog
            position += len(paste)
            line_insert(backlog, extra=paste)
        elif char == input_code['^Z']:
            sigtstp()
        elif char == input_code['enter']:
            finalise_history(history_index, response, replacements,
                             input_replaced, history_modified)
            move_cursor('right', len(response) - position)
            return response
        else:
            backlog = response[position:]
            response = response[:position] + char + backlog
            position += 1
            line_insert(backlog, extra=char)


def main():
    """Called if script isn't imported."""
    # "print(text, end='')" is equivalent to "print text,", and 'flush'
    # forces the text to appear, even if the line isn't terminated with
    # a '\n'
    print('Hello, ', end='', flush=True)
    name = input_no_newline()  # pylint: disable=unused-variable
    print(', how do you do?')


if __name__ == '__main__':
    main()

As you can see, it's a lot of work for not that much since you need to deal with the different operating systems and basically reimplement a built-in function in Python rather than C. I'd recommend that you just use the simpler TempHistory class I made in another answer, which leaves all the complicated logic-handling to the built-in function.

Like Nick K. said, you'll need to move the text cursor back to before the newline was echoed. The problem is that you can't easily get the length of the previous line in order to move rightward, lest you store every string printed, prompted and inputted in its own variable.

Below is a class (for Python 3) that fixes this by automatically storing the last line from the terminal (provided you use its methods). The benefit of this compared to using a terminal control library is that it'll work in the standard terminal for both the latest version of Windows as well as *NIX operating systems. It'll also print the 'Hello, ' prompt before getting input.

If you're on Windows but not v1511 of Windows 10, then you'll need to install the colorama module or else this won't work, since they brought ANSI cursor movement support in that version.

# For the sys.stdout file-like object
import sys
import platform

if platform.system() == 'Windows':
    try:
        import colorama
    except ImportError:
        import ctypes
        kernel32 = ctypes.windll.kernel32
        # Enable ANSI support on Windows 10 v1511
        kernel32.SetConsoleMode(kernel32.GetStdHandle(-11), 7)
    else:
        colorama.init()
else:
    # Fix Linux arrow key support in Python scripts
    import readline


class TempHistory:
    """Record one line from the terminal.

    It is necessary to keep track of the last line on the terminal so we
    can move the text cursor rightward and upward back into the position
    before the newline from the `input` function was echoed.

    Note: I use the term 'echo' to refer to when text is
    shown on the terminal but might not be written to `sys.stdout`.

    """

    def __init__(self):
        """Initialise `line` and save the `print` and `input` functions.

        `line` is initially set to '\n' so that the `record` method
        doesn't raise an error about the string index being out of range.

        """
        self.line = '\n'
        self.builtin_print = print
        self.builtin_input = input

    def _record(self, text):
        """Append to `line` or overwrite it if it has ended."""
        if text == '':
            # You can't record nothing
            return
        # Take into account `text` being multiple lines
        lines = text.split('\n')
        if text[-1] == '\n':
            last_line = lines[-2] + '\n'
            # If `text` ended with a newline, then `text.split('\n')[-1]`
            # would have merely returned the newline, and not the text
            # preceding it
        else:
            last_line = lines[-1]
        # Take into account return characters which overwrite the line
        last_line = last_line.split('\r')[-1]
        # `line` is considered ended if it ends with a newline character
        if self.line[-1] == '\n':
            self.line = last_line
        else:
            self.line += last_line

    def _undo_newline(self):
        """Move text cursor back to its position before echoing newline.

        ANSI escape sequence: `\x1b[{count}{command}`
        `\x1b` is the escape code, and commands `A`, `B`, `C` and `D` are
        for moving the text cursor up, down, forward and backward {count}
        times respectively.

        Thus, after having echoed a newline, the final statement tells
        the terminal to move the text cursor forward to be inline with
        the end of the previous line, and then move up into said line
        (making it the current line again).

        """
        line_length = len(self.line)
        # Take into account (multiple) backspaces which would
        # otherwise artificially increase `line_length`
        for i, char in enumerate(self.line[1:]):
            if char == '\b' and self.line[i-1] != '\b':
                line_length -= 2
        self.print('\x1b[{}C\x1b[1A'.format(line_length),
                   end='', flush=True, record=False)

    def print(self, *args, sep=' ', end='\n', file=sys.stdout, flush=False,
              record=True):
        """Print to `file` and record the printed text.

        Other than recording the printed text, it behaves exactly like
        the built-in `print` function.

        """
        self.builtin_print(*args, sep=sep, end=end, file=file, flush=flush)
        if record:
            text = sep.join([str(arg) for arg in args]) + end
            self._record(text)

    def input(self, prompt='', newline=True, record=True):
        """Return one line of user input and record the echoed text.

        Other than storing the echoed text and optionally stripping the
        echoed newline, it behaves exactly like the built-in `input`
        function.

        """
        if prompt == '':
            # Prevent arrow key overwriting previously printed text by
            # ensuring the built-in `input` function's `prompt` argument
            # isn't empty
            prompt = ' \b'
        response = self.builtin_input(prompt)
        if record:
            self._record(prompt)
            self._record(response)
        if not newline:
            self._undo_newline()
        return response


record = TempHistory()
# For convenience
print = record.print
input = record.input

print('Hello, ', end='', flush=True)
name = input(newline=False)
print(', how do you do?)

As already answered, we can't stop input() from writing a newline. Though it may not satisfy your expectation, somehow the following codes satisfy the condition if -

you don't have any issue clearing the screen

import os
name = input("Hello, ")
os.system("cls") # on linux or mac, use "clear"
print(f"Hello, {name}, how do you do?")

or no issue using the gui dialog box, as dialog box disappears after taking user input, you will see exactly what you expected

import easygui
name = easygui.enterbox("Hello, ", "User Name")
print("Hello, "+name+", how do you do?")

I think you can use this:

 name = input("Hello , ")

It should be something like this:-

print('this eliminates the ', end=' ')

print('new line')

The output is this:-

this eliminates the new line.