NOTE:
pd.convert_objectshas now been deprecated. You should usepd.Series.astype(float)orpd.to_numericas described in other answers.
This is available in 0.11. Forces conversion (or set's to nan)
This will work even when astype will fail; its also series by series
so it won't convert say a complete string column
In [10]: df = DataFrame(dict(A = Series(['1.0','1']), B = Series(['1.0','foo'])))
In [11]: df
Out[11]:
A B
0 1.0 1.0
1 1 foo
In [12]: df.dtypes
Out[12]:
A object
B object
dtype: object
In [13]: df.convert_objects(convert_numeric=True)
Out[13]:
A B
0 1 1
1 1 NaN
In [14]: df.convert_objects(convert_numeric=True).dtypes
Out[14]:
A float64
B float64
dtype: object
Top answer 1 of 7
83
NOTE:
pd.convert_objectshas now been deprecated. You should usepd.Series.astype(float)orpd.to_numericas described in other answers.
This is available in 0.11. Forces conversion (or set's to nan)
This will work even when astype will fail; its also series by series
so it won't convert say a complete string column
In [10]: df = DataFrame(dict(A = Series(['1.0','1']), B = Series(['1.0','foo'])))
In [11]: df
Out[11]:
A B
0 1.0 1.0
1 1 foo
In [12]: df.dtypes
Out[12]:
A object
B object
dtype: object
In [13]: df.convert_objects(convert_numeric=True)
Out[13]:
A B
0 1 1
1 1 NaN
In [14]: df.convert_objects(convert_numeric=True).dtypes
Out[14]:
A float64
B float64
dtype: object
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You can try df.column_name = df.column_name.astype(float). As for the NaN values, you need to specify how they should be converted, but you can use the .fillna method to do it.
Example:
In [12]: df
Out[12]:
a b
0 0.1 0.2
1 NaN 0.3
2 0.4 0.5
In [13]: df.a.values
Out[13]: array(['0.1', nan, '0.4'], dtype=object)
In [14]: df.a = df.a.astype(float).fillna(0.0)
In [15]: df
Out[15]:
a b
0 0.1 0.2
1 0.0 0.3
2 0.4 0.5
In [16]: df.a.values
Out[16]: array([ 0.1, 0. , 0.4])
GeeksforGeeks
geeksforgeeks.org › python › how-to-convert-strings-to-floats-in-pandas-dataframe
How to Convert String to Float in Pandas DataFrame - GeeksforGeeks
July 15, 2025 - Sometimes, we may not have a float value represented as a string. So, pd.to_numeric() function will show an error. To remove this error, we can use errors='coerce', to convert the value at this position to be converted to NaN.
Pandas DataFrame tries to convert a string into a float, while adding it to a column
Well you're using np.nan which is a float. Interestingly though, it only raises the error after the first item has been added. >>> df = pd.DataFrame() >>> df['foo'] = [np.nan] * len(df) >>> df Empty DataFrame Columns: [foo] Index: [] Note the type is float64 >>> df.dtypes foo float64 dtype: object However, pandas converts it. >>> df.at['file_path', 'foo'] = 'file1' >>> df.dtypes foo object dtype: object Second time round, it raises the error - not sure why that is exactly. >>> df['bar'] = [np.nan] * len(df) >>> df.dtypes foo object bar float64 dtype: object >>> df.at['file_path', 'bar'] = 'file1' Traceback (most recent call last): You can use an empty string '' instead of np.nan - or you could initialize your dataframe with values. You may also want to check out pathlib from pathlib import Path file_paths = ... df = pd.DataFrame({ Path(p).stem: [p] for p in file_paths }) .stem from pathlib is the filename without the extension. More on reddit.com
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December 13, 2021Could not convert string to float: ''
Hi to everybody, In pandas I want to convert a string column in a float one, but I get all the time the same error message: could not convert string to float: ‘’ The content of this column is the following: 2019-08-06T16:47:07.508 So I replaced “-”, “T”, “:” and “.” with ... More on discuss.python.org
0
0
June 6, 2024Python pandas - can't convert string to float (I think b/c of multiple data types in column...)
Thanks u/Ihaveamodel3 for the solution, the original post was 95% of the way there. I added coerce & now it seems to work... dfteam1["cloff"] = pd.to_numeric(dfteam1["cloff"],errors='coerce') funny how coerce was needed. Thanks to u/omgu8mynewt for your reply as well. More on reddit.com
5
1
July 17, 2022python - Converting string to float using pandas - Stack Overflow
I have a csv file in which the column has '$' and ',' in it. So, I am unable to replace thementer image description here Please let me know if any solution available. Thank you. More on stackoverflow.com
Videos
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Spark By {Examples}
sparkbyexamples.com › home › pandas › pandas convert column to float in dataframe
Pandas Convert Column to Float in DataFrame - Spark By {Examples}
October 14, 2024 - You can use the Pandas DataFrame.astype() function to convert a column from string/int to float, you can apply this on a specific column or on an entire DataFrame. To cast the data type to a 54-bit signed float, you can use numpy.float64, ...
Statology
statology.org › home › how to convert strings to float in pandas
How to Convert Strings to Float in Pandas
November 28, 2022 - #convert all columns to float df = df.astype(float) #view column data types df.dtypes points float64 assists float64 rebounds float64 dtype: object · The following syntax shows how to convert the assists column from string to float and simultaneously fill in the NaN values with zeros:
Quora
quora.com › How-do-you-convert-a-string-to-a-float-in-pandas
How to convert a string to a float in pandas - Quora
If your talking about a single element, and assuming your using Python, you can just do something like this: a=”yourstring” yourfloat=float(a) finally you need to update your panda series, dataframe o...
Reddit
reddit.com › r/learnpython › pandas dataframe tries to convert a string into a float, while adding it to a column
r/learnpython on Reddit: Pandas DataFrame tries to convert a string into a float, while adding it to a column
December 13, 2021 -
Hello Guys,
I have a question regarding DataFrames. I have a line of code, which looks similar to this:
import os
import pandas as pd
import numpy as np
file_paths = ('C:/Users/DR/Documents/Polymer Science/Mitarbeiterpraktika/Forschungsmodul I Elektrochemie/Wasserspaltung/Co15-FTO_calc_WS_LS.txt', 'C:/Users/DR/Documents/Polymer Science/Mitarbeiterpraktika/Forschungsmodul I Elektrochemie/Wasserspaltung/Co16-FTO_calc_WS_LS.txt')
files_infos = pd.DataFrame()
for n, file_path in enumerate(file_paths) :
file_name = os.path.basename(file_path)
file_name = file_name.split(".txt")[0]
files_infos[file_name] = [np.nan] * len(files_infos)
files_infos.at["file_path", file_name] = file_path
If I run this script I get this Error. ValueError: could not convert string to float: 'C:/Users/DR/Documents/Polymer Science/Mitarbeiterpraktika/Forschungsmodul I Elektrochemie/Wasserspaltung/Co16-FTO_calc_WS_LS.txt'
I just don´t understand, why pandas tries to convert my string into a float. I thougt mabye it has something to do with the dtype of the DataFrame, but I couldn´t really find an answer (the dtype is object). What I find really confusing about this Error is, that I did use the same approach in different projects and it didn´t occur before.
Can someone of you mabye explain to me, why this error occurs and what I have to look up to find a solution? Please dont give me a solution to my problem, since I would like to solve it by myself in order to learn it.
Thank you for your help in advance.
Top answer 1 of 2
2
Well you're using np.nan which is a float. Interestingly though, it only raises the error after the first item has been added. >>> df = pd.DataFrame() >>> df['foo'] = [np.nan] * len(df) >>> df Empty DataFrame Columns: [foo] Index: [] Note the type is float64 >>> df.dtypes foo float64 dtype: object However, pandas converts it. >>> df.at['file_path', 'foo'] = 'file1' >>> df.dtypes foo object dtype: object Second time round, it raises the error - not sure why that is exactly. >>> df['bar'] = [np.nan] * len(df) >>> df.dtypes foo object bar float64 dtype: object >>> df.at['file_path', 'bar'] = 'file1' Traceback (most recent call last): You can use an empty string '' instead of np.nan - or you could initialize your dataframe with values. You may also want to check out pathlib from pathlib import Path file_paths = ... df = pd.DataFrame({ Path(p).stem: [p] for p in file_paths }) .stem from pathlib is the filename without the extension.
2 of 2
1
files_infos[file_name] = [np.nan] * len(files_infos) -->self.files_infos[file_name] = [file_path, np.nan])) so at least i found my solution on my self I still don´t understand why this Error occurs and why pandas tries to convert my string into a float and it would be nice if somebody could still explain it to me.
Wellsr
wellsr.com › python › python-convert-pandas-dataframe-string-to-float-int
Python with Pandas: Convert String to Float and other Numeric Types - wellsr.com
November 9, 2018 - This method has the format [dtype2 ... to help it make more sense. Strings can be converted to floats using the astype method with the Numpy data type numpy.float64:...
DigitalOcean
digitalocean.com › community › tutorials › python-convert-string-to-float
How to Convert String to Float in Python: Complete Guide with Examples | DigitalOcean
July 10, 2025 - Learn how to convert strings to floats in Python using float(). Includes syntax, examples, error handling tips, and real-world use cases for data parsing.
Saturn Cloud
saturncloud.io › blog › how-to-convert-a-column-in-pandas-dataframe-from-string-to-float
How to Convert a Column in Pandas DataFrame from String to Float | Saturn Cloud Blog
October 27, 2023 - Converting a column in a pandas DataFrame from a string to a float is a simple task that can be accomplished using the astype() method. In this blog post, we covered the steps required to convert a column from a string to a float.
Python.org
discuss.python.org › python help
Could not convert string to float: '' - Python Help - Discussions on Python.org
June 6, 2024 - Hi to everybody, In pandas I want to convert a string column in a float one, but I get all the time the same error message: could not convert string to float: ‘’ The content of this column is the following: 2019-08-06T16:47:07.508 So I replaced “-”, “T”, “:” and “.” with following code: climbing[“UTC time”] = climbing[“UTC time”].replace(“-”, “”, regex=True) climbing[“UTC time”] = climbing[“UTC time”].replace(“:”, “”, regex=True) climbing[“UTC time”] = climbing[“UTC time”].replace(“.”, “”,...
Reddit
reddit.com › r/learnpython › python pandas - can't convert string to float (i think b/c of multiple data types in column...)
r/learnpython on Reddit: Python pandas - can't convert string to float (I think b/c of multiple data types in column...)
July 17, 2022 -
I want to do some math on a dataframe but (I think) can't get one column/series into the necessary format. The column contains strings; some are '.123' while others are '0'. When I attempt the math on the column of strings by converting everything to an integer like so:
dfteam1['cloff'] = dfteam1.cloff.astype(int)
I get the following error
ValueError: invalid literal for int() with base 10: '.123'
I think it's b/c .123 isn't an integer but a float, so I change the code like so:
dfteam1['cloff'] = dfteam1.cloff.astype(float)
now I get the following error
ValueError: could not convert string to float:
I think it's b/c 0 isn't a float but an integer? Do I need to change all the 0 values to 0.00 or am I completely off base? All feedback is welcome.
Top answer 1 of 3
1
Thanks u/Ihaveamodel3 for the solution, the original post was 95% of the way there. I added coerce & now it seems to work... dfteam1["cloff"] = pd.to_numeric(dfteam1["cloff"],errors='coerce') funny how coerce was needed. Thanks to u/omgu8mynewt for your reply as well.
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I don't think its because you want an integer but have a float, the error code is literally telling you it is a string. Somewhere in your column you have a string? is the first error, ValueError: invalid literal for int() with base 10: '.123', that last value ".123" a string when it should be an integer or float? Edit: I just tested and I get the same errors, I think your "0.127" string variable when it shouldn't be. Not sure why it can't be changed to a float though, me messing around with a "0.127" and I can change it to a float but not an int. Somewhere else in your column you have a value you think is a float but is actually a string that can't be changed to a float?
GoLinuxCloud
golinuxcloud.com › home › python pandas › convert pandas dataframe column to float (astype, to_numeric & practical examples)
Convert pandas DataFrame Column to Float (astype, to_numeric & Practical Examples) | GoLinuxCloud
January 24, 2022 - ... import pandas as pd df = ... If a column contains numeric values stored as strings, you can convert them to float using astype()....
Cherry Servers
cherryservers.com › home › blog › python › how to convert string to float in python (6 different ways)
How to Convert String to Float in Python (6 Different Ways) | Cherry Servers
July 25, 2024 - ... Using the float() function is the most common way to convert string to float in Python. What’s more, it is a built-in function which means it comes with standard Python installation.
Practical Business Python
pbpython.com › currency-cleanup.html
Cleaning Up Currency Data with Pandas - Practical Business Python
To illustrate the problem, and build the solution; I will show a quick example of a similar problem using only python data types. First, build a numeric and string variable. number = 1235 number_string = '$1,235' print(type(number_string), type(number)) ... This example is similar to our data in that we have a string and an integer. If we want to clean up the string to remove the extra characters and convert to a float:
GitHub
gist.github.com › Keiku › b3e0038a2d1145ea82eda8444b98c02a
Convert number strings with commas in pandas DataFrame to float. · GitHub
Convert number strings with commas in pandas DataFrame to float. - convert_number_strings_to_numbers.py
Statology
statology.org › home › how to fix in pandas: could not convert string to float
How to Fix in Pandas: could not convert string to float
July 16, 2022 - Notice that we’re able to convert the revenue column from a string to a float and we don’t receive any error since we removed the dollar signs before performing the conversion. The following tutorials explain how to fix other common errors in Python:
Stack Overflow
stackoverflow.com › questions › 74003247 › converting-string-to-float-using-pandas › 74003278
python - Converting string to float using pandas - Stack Overflow
Try dfnew['StartingMedianSalary'] = dfnew['StartingMedianSalary'].str.replace(',', '').str.replace('$', '').astype(float).
Pandas
pandas.pydata.org › docs › reference › api › pandas.to_numeric.html
pandas.to_numeric — pandas 3.0.1 documentation - PyData |
Convert dtypes. ... >>> s = pd.Series(["1.0", "2", -3]) >>> pd.to_numeric(s) 0 1.0 1 2.0 2 -3.0 dtype: float64 >>> pd.to_numeric(s, downcast="float") 0 1.0 1 2.0 2 -3.0 dtype: float32 >>> pd.to_numeric(s, downcast="signed") 0 1 1 2 2 -3 dtype: int8 >>> s = pd.Series(["apple", "1.0", "2", -3]) >>> pd.to_numeric(s, errors="coerce") 0 NaN 1 1.0 2 2.0 3 -3.0 dtype: float64
Reddit
reddit.com › r/learnpython › how i convert float to string in this case?
r/learnpython on Reddit: How I convert float to string in this case?
August 21, 2022 -
I tried
n1=input('First number')
n2=input('Second number')
sum = float(n1) + float(n2)
str(sum)
print('The sum of the values is: ' + sum)My error is:
TypeError: can only concatenate str (not "float") to str
I tried googling this error and got some answers like print(f' which I didn't really understand, and some others that looked a little complicated, I am very new.
I am trying to improve my googling skills.
Top answer 1 of 4
4
You shouldn't call your variable sum, as that's a name of a built in function: https://docs.python.org/3/library/functions.html#sum Your problem however, stems from trying to add a string to a float. Could you please tell me, what is Adam + 5? Well, you can't, because it makes no mathematical sense. You didn't save the string representation str(sum), so sum never changed to a string What your research found is f-strings and they are very easy to use. Try: print(f"the sum of the values is {sum}") Simply, put an f before a string starts, then any string that you want goes between " and ", while any variables or other values go between { and }
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Just as you converted the strings to floats with float(), you can do the opposite with str(). print("The sum of the values is: " + str(sum)) Now, print() can also take multiple arguments, so you instead of the + for string concatenation, you can do this: print("The sum of the values is:", sum) Now, you should learn f-string formatting. It's not tough once you get the hang of it. print(f"The sum of the values is: {sum}") # no format control print(f"The sum of the values is: {sum:.2f}") # 2-decimal places That says, "Format the floating point number, sum, to two decimal places." And, do not use sum for a variable name. Doing so overwrites the sum() function.