How do I put a variable inside a string

Question

I would like to put an int into a string  This is what I am doing at the moment   num   40 plot savefig  hanning40 pdf    problem line   I have to run the program for several different numbers  so I d like to do a loop  But inserting the variable like this doesn t work   plot savefig  hanning   num    pdf     How do I insert a variable into a Python string

User · Accepted Answer

plot savefig  hanning  d  pdf    num    The   operator  when following a string  allows you to insert values into that string via format codes  the  d in this case   For more details  see the Python documentation   https   docs python org 3 library stdtypes html printf-style-string-formatting

User · Answer

You just have to cast the num varriable into a string using   str num

User · Answer

With the introduction of formatted string literals   f-strings  for short  in Python 3 6  it is now possible to write this with a briefer syntax    gt  gt  gt  name    Fred   gt  gt  gt  f He said his name is  name     He said his name is Fred     With the example given in the question  it would look like this  plot savefig f hanning num  pdf

User · Answer

Oh  the many  many ways     String concatenation   plot savefig  hanning    str num      pdf     Conversion Specifier   plot savefig  hanning s pdf    num    Using local variable names   plot savefig  hanning  num s pdf    locals      Neat trick   Using str format     plot savefig  hanning 0  pdf  format num     Note  This is the new preferred way   Using f-strings   plot savefig f hanning num  pdf     added in Python 3 6   Using string Template   plot savefig string Template  hanning  num  pdf   substitute locals

User · Answer

If you would want to put multiple values into the string you could make use of format  nums    1 2 3  plot savefig  hanning 0  1  2  pdf  format  nums     Would result in the string hanning123 pdf  This can be done with any array

User · Answer

In general  you can create strings using   stringExample    someString     str someNumber  print stringExample  plot savefig stringExample

User · Answer

Not sure exactly what all the code you posted does  but to answer the question posed in the title  you can use   as the normal string concat function as well as str        hello     str 10      world     hello 10 world    Hope that helps

User · Answer

I had a need for an extended version of this  instead of embedding a single number in a string  I needed to generate a series of file names of the form  file1 pdf    file2 pdf  etc  This is how it worked     file    str i      pdf  for i in range 1 4

[python] How do I put a variable inside a string?

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