User restrictions integer

Question

How to narrow input of a integer to a certain length like "7" (per example) from a user raw_input:

def number():
number=int(input("Number:"))
print(number)

number=1234567

It has to have an while condition where it says if len(number) < 7 or len(number) > 7:

print("Error")
phone=int(input("Number:"))`

Thank you & Merry Xmas

Possible duplicate of [Limiting Python input strings to certain characters and lengths](http://stackoverflow.com/questions/8761778/limiting-python-input-strings-to-certain-characters-and-lengths) — Abhishek Singh, Dec 24 '15 at 18:59
@AbhishekSingh this is an individual and special case where I need it to be a raw_input and a integer only. — Phyti, Dec 24 '15 at 19:05
@Phyti, raw_input is python2, your quaetion is tagged python3 — Padraic Cunningham, Dec 24 '15 at 19:07
@PadraicCunningham your code returns the following error: TypeError: object of type 'int' has no len() — Phyti, Dec 24 '15 at 19:20
@Phyti, not unless you are using python2 or not using my code exactly as posted — Padraic Cunningham, Dec 24 '15 at 19:25
@PadraicCunningham solved the error but is allowing to put more than 7 and less I just wanted 7 is there a way to simplify this with if statements and else, inside the While? — Phyti, Dec 24 '15 at 19:33
@Phyti, it is not letting you put more than 7, if you want exactly 7 I have alsoexplained how to do that in my answer — Padraic Cunningham, Dec 24 '15 at 19:34
@PadraicCunningham I done it and just saw that now on Comments. Thank you and Merry Xmas — Phyti, Dec 24 '15 at 19:37

score 2 · Accepted Answer · answered Dec 24 '15 at 19:01

2

check the length before you try casting to int:

def number():
    while True:
        i = input("Number:") 
        if len(i) > 7:
            print("Number can only contain at most 7 digits!")
            continue
        try:
            return int(i)
        except ValueError:
            print("Invalid input")

If you want exactly 7 use if len(i) != 7 and adjust the error message accordingly. I also used a try/except as because the length is seven does not mean it is a valid string of digits. If you want to allow the minus son you could if len(i.lstrip("-")) > 7:

answered Dec 24 '15 at 19:01

Padraic Cunningham

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I have to say if len(number)<7 or len(number)>7: print("Input Invalid") and to print again raw_input(int("Number")). – Phyti Dec 24 '15 at 19:10
1

You don't use number at all, you check the length if i and only try casting to int if it is an acceptable length, if you want at most a 7 digit number then `if len(i) > 7:` will work as you want as any length > 7 will not be ignored – Padraic Cunningham Dec 24 '15 at 19:13
2

just run the code @Phyti .. the `while True` keeps reprompting until correct input is recieved ... – Joran Beasley Dec 24 '15 at 19:13
Ok I will @JoranBeasley – Phyti Dec 24 '15 at 19:16

User restrictions integer

1 Answers1