How to tell if string starts with a number with Python

Question

I have a string that starts with a number  from 0-9  I know I can  or  10 test cases using startswith   but there is probably a neater solution  so instead of writing  if  string startswith  0      string startswith  2          string startswith  3      string startswith  4          string startswith  5      string startswith  6          string startswith  7      string startswith  8          string startswith  9          do something   Is there a cleverer more efficient way

User · Answer

You could use regular expressions   You can detect digits using   if re search  0-9   yourstring  1      do something   The  0-9  par matches any digit  and yourstring  1  matches the first character of your string

User · Answer

This piece of code   for s in   fukushima    123 is a number            print s ljust 20    s 0  isdigit   if s else False   prints out the following   fukushima            False 123 is a number      True                      False

User · Answer

Here are my  answers   trying to be unique here  I don t actually recommend either for this particular case  -   Using ord   and the special a  lt   b  lt   c form     starts with digit   ord  0    lt   ord mystring 0    lt   ord  9     I was thinking too much in C  Strings are perfectly comparable  starts with digit    0   lt   mystring 0   lt    9     This a  lt   b  lt   c  like a  lt  b  lt  c  is a special Python construct and it s kind of neat  compare 1  lt  2  lt  3  true  and 1  lt  3  lt  2  false  and  1  lt  3   lt  2  true   This isn t how it works in most other languages    Using a regular expression   import re   starts with digit   re match r   d   mystring  is not None   re match is already anchored starts with digit   re match r  d   mystring  is not None

User · Answer

Python s string library has isdigit   method   string 0  isdigit

User · Answer

You can also use try   except   try      int string 0         do your stuff except      pass   or do your stuff

User · Answer

Surprising that after such a long time there is still the best answer missing   The downside of the other answers is using  0  to select the first character  but as noted  this breaks on the empty string   Using the following circumvents this problem  and  in my opinion  gives the prettiest and most readable syntax of the options we have  It also does not import bother with regex either     gt  gt  gt  string    1abc   gt  gt  gt  string  1  isdigit   True   gt  gt  gt  string       gt  gt  gt  string  1  isdigit   False

User · Answer

Use Regular Expressions  if you are going to somehow extend method s functionality

User · Answer

Try this   if string 0  in range 10

User · Answer

sometimes  you can use regex   gt  gt  gt  import re  gt  gt  gt  re search    s  0-9    0abc    lt  sre SRE Match object at 0xb7722fa8 gt

User · Answer

gt  gt  gt  string    1abc   gt  gt  gt  string 0  isdigit   True

User · Answer

Your code won t work  you need or instead of      Try   0   lt   strg  1   lt    9    or  strg  1  in  0123456789    or  if you are really crazy about startswith   strg startswith   0    1    2    3    4    5    6    7    8    9

[python] How to tell if string starts with a number with Python?

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