CODEWITHSUNDEEP
pythonstringpython-3.xfloating-point
Udit Kumawat
Udit Kumawat

Reputation: 684

why python not converts float or any other data type to string when written with string?

Suppose 

p1="python"
p2="script"
r=0.242424

print(p1+" "+p2+" "+r)          #wrong or error in python
print(p1+" "+p2+" "+str(r))       #correct

Why do I we have to convert a float to string explicitly in Python, but other languages like Java convert it implicitly?

Upvotes: 0

Views: 124

Answers (2)

Aaron Hall
Aaron Hall

Reputation: 395285

If you want to join various data types into a string, concatenation with + or with the str.join method will require them to be strings before you do it.

As Martijn shows, it's not needed for printing, but that can be confusing because printing by default includes newlines and a space that separates elements separated by commas that are being printed.

If you want to implicitly convert them to strings, I recomend the string.format method:

>>> '{0} {1} {2}'.format(p1, p2, r)
'python script 0.242424'

This is quite a useful and efficient way to format text and not have to worry about the types, so long as you don't mind getting their default string representation.

Upvotes: 0

Martijn Pieters
Martijn Pieters

Reputation: 1123052

You don't. You only need to convert it explicitly when concatenating. print() will use spaces to separate arguments on its own, converting each to a string:

print(p1, p2, r)

Quoting the print() documentation:

All non-keyword arguments are converted to strings like str() does and written to the stream, separated by sep and followed by end.

sep defaults to the ' ' string.

You usually use string formatting to interpolate values into a string:

print("Running a {} {} to show the value of r={:.6f}".format(p1, p2, r))

Otherwise, trying to concatenate strings with other values does not convert values implicitly; this goes against the Zen of Python:

Explicit is better than implicit.

Upvotes: 3

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